Crystal structure and phase transitions across the metal-superconductor boundary in the SmF
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第49卷第12期人工晶体学报Vol.49No.12 2020年12月JOURNAL OF SYNTHETIC CRYSTALS December,2020 InSei单晶的制备及其结构与性能研究周玄1,2,程国峰2,何代华1(1.上海理工大学材料科学与工程学院,上海200093;2.中国科学院上海硅酸盐研究所,上海200050)摘要:利用化学气相传输法(CVT)制备了InSeI单晶。
该晶体为黄色的针状物,晶体较脆。
在室温下进行X射线衍射分析发现,其属于四方晶系,晶胞参数为a=b=1.8643(5)nm,c=1.0120(3)nm,V=3.5172nm3,空间群为他/a。
紫外可见光吸收光谱、光致发光光谱等结果显示该晶体的禁带宽度是2.48eV,在一定波段光的激发下,InSeI单晶在600nm左右有较宽的发射峰,表明该晶体的发光方式为缺陷态发光。
介电温谱表明InSeI单晶在440K时其四方相的结构发生了相变。
关键词:InSeI;金属基硫卤化合物;化学气相传输法;光致发光;禁带宽度;介电性能中图分类号:O78文献标识码:A文章编号:1000-985X(2020)12-225244 Synthesis,Structure and Properties of InSei Single CrystalsZHOU Xuan1,2,CHENG Guofeng2,HE Daihua1(1.School of Materials Science and Engineering,Lniversity of Shanghai for Science and Technology,Shanghai200093,China;2.Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai200050,China)Abstract:InSeI single crystals were synthesized by the chemical vapor transport(CVT)method.The crystal is yellow needleshaped and brittle.X-ray diffraction results at room temperature show the tetragonal system of InSeI,with lattice parameters of a=b=1.8643(5)nm,c=1.0120(3)nm,V=3.5172nm3,and space group is/a.The ultraviolet-visible absorption spectrum,photoluminescence spectrum results show that InSeI has a2.48eV band gap,under the excitation of a certain band of light,InSeI single crystal has a wide emission peak at about600nm,which indicates that the luminescence mode of the crystal is defect state luminescence.The dielectric temperature spectrum indicates that a phase transition happened in the tetragonal structure of InSeI crystals at440K.Key words:InSeI;metal based thiohalide;chemical vapor transport method;photoluminescence;band gap;dielectric property0引言近年来,金属基硫卤化合物MQX[1](M=Ga,In,Sb,Bi;Q=S,Se,Te;X=Cl,Br,I)由于其独特的光电性质如铁电性[2-3]、热电性[4]、光电导性[5]和非线性光学性能[6]等引起了科学界的浓厚兴趣。
THE CRYSTAL STRUCTURE OF THE b0PHASE INAl±Mg±Si ALLOYSS.J.ANDERSEN1,2,H.W.ZANDBERGEN2,J.JANSEN2,3,C.TRáHOLT2,U.TUNDAL4and O.REISO41SINTEF Materials Technology,Applied Physics,7034Trondheim,Norway,2National Centre for HREM,Laboratory of Materials Science,Delft University of Technology,Rotterdamseweg137,2628 AL Delft,The Netherlands,3Laboratory for Crystallography,University of Amsterdam,Nieuwe Achtergracht166,1018WV Amsterdam,The Netherlands and4HYDRO Aluminium,Metallurgical Rand D Centre,Sunndalsùra,Norway(Received17November1997)AbstractÐThe crystal structure of b0,one of the strengthening phases in the commercially important Al±Mg±Si alloys,is determined by use of high resolution electron microscopy(HREM)and electron di raction(ED).A trial structure was established from exit wave phase reconstructed HREM images.A least-square re®nement of the model coordinates was done using data from digitally recorded ED patterns.A recently developed computer program(MSLS)was applied,taking into account dynamic scattering.The atomic unit cell contains two units of Mg5Si6.It is C-centred monoclinic,space group C2/m, a=1.51620.002nm,b=0.405nm,c=0.67420.002nm,b=105.320.58.The atomic packing may be regarded as a hard ball packing using clusters,the clusters being(1)centred tetragons of Mg atoms and(2) so-called twin icosacaps where Mg atoms are centred above and below pentagonal rings of four Si atoms an one Mg atom.A growth related stacking fault in the structure is explained by a de®ciency of Mg atoms.A model for the b0/Al interface is given.#1998Acta Metallurgica Inc.1.INTRODUCTION1.1.GeneralThe discovery of the precipitation hardening mech-anism in the beginning of this century in an Al±Cu alloy has had great implications for all technologies requiring light alloys with some strength,and es-pecially for the aerospace and construction technol-ogies.The increase in hardness that the commercial Al alloys achieve upon hardening is usually a factor of2or more.In the Al±Mg±Si(6xxx)alloys such a tremendous increase in strength is caused by pre-cipitates formed from solution,of merely1wt%of Mg and Si that is added to the aluminium.The maximum hardness is achieved when the alloy con-tains a combination of very®ne fully coherent so-called Guinier Preston(GP-I)zones with diameters about2.5nm,and the semicoherent,larger needles, b0(GP-II zones)with a typical size4Â4Â50nm3. The density of these phases is very high.For the b0 needles,a number density in the matrix of about 104/m m3is normal.This is equal to a volume of nearly1%in the material.The6xxx series alloys are not among the strongest aluminium alloys,but they represent a high share of the aluminium pro-ducts in the world(H20%).In1989,about90%of the tonnage extruded in western Europe,was Al±Mg±Si alloys[1].1.2.The precipitation/transformation sequenceThe phases occurring in the Al±Mg±Si alloys have been studied for more than50years due to the commercial importance of these materials.In1948 Geisler and Hill[2]and Gunier and Lambot[3] reported that X-ray Laue pattern zones indicated the formation of small(H2Â2Â10nm3)needles or Guinier Preston(GP)zones,when the temperature was raised to2008C.Further heating caused the zones to thicken into rods,called b',and®nally a large plate-shaped equilibrium phase,b,was seen to form.The latter was known to be of the f.c.c.CaF2 type with a composition Mg2Si.The alloys that were studied were close to the Al±Mg2Si section of the Al±Mg±Si phase diagram;therefore it was assumed that the composition of all the Mg±Si con-taining phases was ter experiments have shown that the precipitation and transformation is quite complicated and that except for the equili-brium phase,b,the phases involved do not have the stoichiometric ratio Mg2Si.In Table1the transformation sequence at low ageing temperatures for alloys near the quasi-binary section Al±Mg2Si of the phase diagram is summar-ised.The range of existence and sizes of the b'rods and b plates depend not only on the heat-treatment, but on several other factors as well,such as cooling rate from homogenisation or extrusion and the number of Al±Fe(+Mn)±Si containing phases (dispersoids)in the material.This will not be dis-cussed in this paper.In the following a discussion of the precipitation/ transformation sequence shown in Table1is given.Acta mater.Vol.46,No.9,pp.3283±3298,1998#1998Acta Metallurgica Inc.Published by Elsevier Science Ltd.All rights reservedPrinted in Great Britain1359-6454/98$19.00+0.00 PII:S1359-6454(97)00493-X32831.2.1.Atomic clusters.After rapid cooling from homogenisation or extrusion the material is super-saturated with Mg and Si.Due to the higher solubi-lity of Mg in Al,when stored at room temperature or heated,Si ®rst goes out of solution and forms small clusters,but there are also some indications of clustering of Mg [5].The nucleation of Si-clusters will occur at quenched-in vacancies at temperatures as low as À508,below which the vacancy movement becomes very low [6].Storing or heating above À508will cause Mg to di use to the clusters,and Mg±Si phases will pre-cipitate.The di usion of Mg to the Si clusters has been veri®ed through APFIM [5,7]where the ratio of Mg/Si in the average cluster was found to increase with time when heated at 708.Since the number of Si clusters formed will be important for the precipitation of the strengthening GP zones,the storing time at a low temperature before arti®cial ageing is important concerning the material proper-ties.1.2.2.GP zones and the b 0phase .The ®rst phase to precipitate on the small clusters is the GP zones.Based on a TEM study of Al±Mg 2Si [8]Thomas proposed a model for these particles;Mg and Si replace Al in such a ratio that the occupied volume is about the same.He proposed a simple substi-tution along 110-directions with strings of atoms in the sequence Mg±Si±Mg±Mg±Si±Mg.Here two di-ameters of Mg (2Â0.32nm)and one of Si (0.235nm)amounts to 0.874nm,as compared with three diameters of Al (0.859nm).In more recent research the evolution of GP zones in several Al±Mg 2Si alloys was studied by calorimetry [6],in 6061by calorimetry and TEM [5],and by atom-probe ®eld-ion microscopy (APFIM)and TEM/HREM [5,7].These works support the view that there are at least two phases in the size range of the GP-zones,called GP-I and GP-II.For the GP-I type the size is in the range 1±3nm.The crystal structure is unknown.The zones are fully coherent and probably have a spherical shape.Dutta and Allen [9]observed by TEM small spot-like features of ``unresolved''shape of about 2.5nm that should be the GP-I zones.Particles investigated by APFIM [5]with comparable dimensions to these zones seem to have Mg/Si ratios usually less than 1.This composition is therefore di erent from that of the model proposed by Thomas [8].The GP-II zone is the same phase as the currently investigated b 0phase.This phase has the shape of ®ne needles,typically about 4Â4Â50nm 3when the material is in the aged-hardened condition [7,10].In this condition the number density of the nee-dles is high;typically 104/m m 3[10].The b 0phase is fully coherent only along the b -axis.Edwards et al.[7]managed to determine the unit cell of the b 0phase by electron di raction.It was found to be a monoclinic C-centred structure with a =0.153420.012nm,b =0.405nm,c =0.68320.015nm,b =10621.58.The b -axis is along the needle-axis.It is the full coherency of GP-I zones,the semi-coherency of the GP-II zones together with their high number densities that introduce in the alu-minium matrix strain and resistance against move-ment of dislocations,that gives the material its mechanical strength.1.2.3.The b 'phase .The next phase in the trans-formation sequence after the GP-I zones and the b 0phase is the b 'phase.This has a lower Mg/Si ratio than the equilibrium b phase.Lynch et al.found by X-ray microanalysis evidence for a ratio of Mg/Si in the b 'rods in an overaged material to be about 1.73[11],while Matsuma et al.[12]later determined the ratio to be about 1.68.For materials with excess silicon relative to Al±Mg 2Si there may be very small precipitates also of the b 'and a so-called B 'phase that is richer in silicon,or even Si particles [4].Because of this such particles with sizes comparable to b 0[7,4]may be mistaken for the b 0phase.The b 'and the B 'phase are reported as having the hexa-gonal unit cells a =0.705nm,c =0.405nm and a =0.104nm,c =0.405nm,respectively.In Refs [7,4]the relative number of b 0as compared with the smallest b '(and B ')particles was not deter-mined.It was recently suggested that b 'is a h.c.p.structure with a =0.405nm,c =0.67nm [12,13].1.2.4.The b phase.The b phase is the equilibrium phase in this system.It is the only phase up to now with a known structure.It is a CaF 2type f.c.c.structure with a =0.639nm having formula Mg 2Si.The structure may be described as strings of three atoms,Mg±Si±Mg,on the corners and faces of a cube,directed along the diagonals.Table 1.The evolution of Mg±Si phases near the quasi-binary section Al±Mg 2Si (top to bottom)Transformation/precipitation sequence Crystal type Size (nm)Composition Clusters of Si and fewer of Mg unknown unknown Si (Mg)Clusters containing Si and Mg unknown unknown Mg/Si <1Coherent spherical GP-I zonesunknown H 1±3Mg/Si H 1Semi-coherent GP-II zones (b 0needles)monoclinic H 4Â4Â50Mg/Si r 1b 'rods (and B 'rods)hexagonal H 20Â20Â500Mg/Si H 1.7b -Mg 2Si platescubicmicronsMg/Si =2The B 'phase is observed with alloys having excess Si relative to Al±Mg 2Si.It contains more Si than b '[4].ANDERSEN et al.:Al±Mg±Si ALLOY32841.3.SummationSumming up the information above,it appears that the phases that evolve from the very®ne Si-clusters into coarser particles take up progressively more magnesium during the coarsening and trans-formation processes,until an equilibrium compo-sition Mg2Si for the b phase®nally is reached.In this paper we report the structure determi-nation of the b0phase,which must be one of the important hardening phases in the commercial6xxx alloys.The technique used in the structure determi-nation is the through focus exit wave reconstruction technique in high resolution electron microscopy,in combination with quantitative electron di raction.2.EXPERIMENTAL2.1.Material and sample preparationThe as-received material was in the shape of extruded sections.It was supplied by HYDRO Aluminium AS(Sunndalsùra).The composition of the material was Al±0.2Fe±0.5Mg±0.53Si±0.01Mn (wt%).The material is from the same batch and extruded sections as investigated in Refs[10,14], there labelled as A and C,respectively.Specimen preparation and location in the extruded section of the samples for TEM are described in Refs[10,14]. Prior to the arti®cial ageing(5h at1858)the ma-terial had undergone a rather standard processing for an extrusion product.After the jet-polishing, specimens were stored in methanol.Most of the TEM experiments were performed within a day after specimen preparation.2.2.TEM equipment and experimental dataAll TEM work was performed using a PHILIPS CM30-ST/FEG electron microscope operated at 300kV.The microscope is equipped with a Photometrix1024Â1024slow scan CCD camera (12bits dynamical range),enabling a linear record-ing of HREM and ED puter control of the CCD camera and the microscope is handled with a Tietz software package.In this way series of 15±20HREM images with focus increments of typi-cally 5.2nm were recorded for each exit wave reconstruction.For the high resolution work suitable aluminium grains were selected and tilted into a h100i zone axis.HREM images were recorded at room tem-perature on as thin areas as possible,typically4±10nm.Needles were selected that could be viewed along their[010]zone axis.In this situation,the needles usually extend through the whole thickness of the specimen,such that no image blurring occurs due to overlap with the matrix.For a single image, the exposure time was usually about1s.For the di raction experiments a small spot-size (5±10nm)was used with exposure times of1±5s. Two zone-axes of the needles were chosen;[010]and[001].For the latter,the aluminium grain was tilted to a h310i zone axis,where statistically one out of six needles is in the correct orientation. Many of the needles contain stacking-faults or sec-ond phases.For a reliable structure determination it is important that the area where a di raction pat-tern is taken is free of defects.Given the resolution of the microscope it should be relatively easy to select single crystalline b0particles.However,to prevent the rapid contamination of the illuminated area that is typical for this kind of specimen at room temperature,the specimen was cooled to about100K.The sample cooling holder has a much poorer mechanical stability resulting in such a loss of resolution that selection of single crystal b0particles was di cult.Because of this ED pat-terns were taken from each particle encountered. Therefore quite many di raction patterns had to be discarded because of streaking and twinning prob-ably caused by the stacking-faults or sometimes extra spots caused by a intergrown phase that was determined to be b'.Five[010]di raction patterns were selected.For the[001]zone axis there is a greater chance of``cross-talk''due to more overlap of the matrix with the crystal,and suitable di rac-tion patterns for the re®nement were more di cult to®nd.Here®ve of the16recorded patterns were from the correct projection or particle.Only two of these patterns could later be re®ned.In addition to the problem with overlap spots from the b'phase, the reason was also the strong interference with the aluminium matrix in this projection that made sub-traction of the background di cult.The thickness of the investigated areas were somewhat larger for the di raction experiments than for the HREM ex-periments.The subsequent re®nements showed that the thickness usually exceeded10nm.In Fig.6, parts of two of the digitally recorded di raction images are shown.This®gure also shows some streaking caused by oversaturation of the CCD camera,which was not equipped with over¯ow pro-tection.The streaks and the aluminium di raction re¯ections were excluded from the images prior to data reduction.The exit wave reconstruction of the HREM focus series were done with a software package based on algorithms developed by Van Dyck and Coene[15±17].Given the coherency of the presently available ®eld emission guns the structural information in ordinary HREM images goes well beyond the point-to-point resolution in the electron microscope. The reconstruction method takes advantage of the knowledge about the transfer function,e.g.how the microscope optics distorts the electron wave after leaving the crystal(the exit wave)on its way to the image plane.This distortion is also a function of defocus.A series of HREM images are recorded at intervals of known defocus.The amplitude and phase information that is mixed up in the HREM images is retrieved through digital processing,andANDERSEN et al.:Al±Mg±Si ALLOY3285corrections for focus and spherical aberration are done.Furthermore,since typically15±20images are used in the reconstruction a considerable reduction in noise is attained.The exit wave is thus independent of various aberrations of the electron microscope, but it is still dependent on the specimen thickness. Only for very small specimen thicknesses is the exit wave very similar to the projected potential,viz.the projected atomic structure.For thicker sections,e.g. more than about10nm for the presently presented exit wave image,the local contrast in the exit wave can be quite di erent from the local scattering poten-tial.Thus,for such thicknesses a higher brightness at a certain point in the phase image of the exit wave as compared to other points,does not have to imply the presence of a locally more strongly scattering atom at this point.The good news is that the positions of the bright dots should correlate well with the location of the atoms.In the presently used electron microscope the res-olution is enhanced from0.20nm to about0.14nm. The HREM images presented in this work are recombined exit wave phase images.See Coene et al.[17],Zandbergen et al.[18]and Op de Beeck et al.[19]for examples and discussion of the method. The re®nement of the structure was done using the computer programme package MSLS[20].The CCD images with the di raction patterns were cor-rected for the¯at®eld(variation in the pixel sensi-tivity)and over¯ow during read-out of the CCD camera.Spurious X-ray signals and the Al di rac-tion spots were omitted.Automatic indexing and data reduction on the patterns were done.The obtained two-dimensional indices of the images were next transformed into the correct hkl indices so that the di raction data sets could be combined. MSLS was used for re®nement of the trial structure coordinates as obtained from the reconstructed exit wave.This program re®nes coordinates based on the least-squares procedure using the multi-slice al-gorithm to account for the dynamic di raction.The parameters re®ned were the thickness,the scaling factor,the centre of the Laue circle for each of the data sets,and the atomic coordinates and tempera-ture factors.The R-value used as measure of the correctness of the structure is de®ned as R=a(I calcÀI obs)2/a(I obs)2.Only the signi®cant re¯ections(I obs>2s(I obs))were used.R-values between2and6%are being quoted for the most reliably determined structures.3.RESULTS/DISCUSSION3.1.Conventional HREM/TEMConventional TEM shows the interior of the Al grains to mainly contain particles having a®ne nee-dle shape.The needles lay along h100i Al directions. Figure1gives an example.It is a bright®eld image in an Al h100i zone axis where the needles clearly point in two normal directions.The dark spots are needles pointing in the viewing direction.The exper-imental di raction patterns as well as HREM images show that the needle shaped particles mostly are of one kind,the monoclinic phase that is usually referred to as the b0phase.Figure2shows a HREM image with one such needle.Such images show the precipitates to be coherent along the nee-dle direction(their b-axis)with a h100i Al direction. This con®rms that their cell parameter is the same as aluminium,b=0.405nm.Many of the b0precipitates were found to con-tain stacking faults.In some precipitates an inter-growth of b0with another phase was observed.It is most probably the b'phase which has the hexago-nal axis along the needle direction.Sometimes this phase was found to exist alone.The cell parameter a=0.705nm has been con®rmed from exit wave simulated images.These images will be published later.In the same material coarser rods of the b' phase have earlier been investigated;It was reported that they nucleate on®ne Al±Fe±Si particles[14].It may be expected that much of the b'particles nucle-ate on b0since with longer arti®cial ageing times the micro-structure will contain an increasing amount of rods of b'.By selected area electron dif-fraction the coarse b'phase in this material was determined to have a hexagonal structure with a H0.71nm,c H0.41nm.The a-axis therefore®ts well with the phase intergrown with b0.The struc-ture of the small and large b'is therefore probably the same.We did not observe any B'phase in the material.3.2.Elemental analysis of the b0phaseWe performed several X-ray analyses of the small precipitates with the spot along the needle axis. Due to the very thin specimen areas(10±40nm)the spectra obtained should in principle not be signi®-cantly in¯uenced by absorption in the specimen, which is the most important reason for deviations from the actual concentration.In spite of the small size of the spot(1±2nm),there was always an Al peak present in the spectrum,of varying height. This is partly caused by stray electrons travelling down the column of the electron microscope which are not focused with the rest of the electrons in the beam probe and therefore many hit aluminium. Secondly,because during analysis the beam is par-allel to the needle axis,i.e.to the[010]zone axis of b0,this implies an e ective beam broadening by the elastic scattering of some electrons into aluminium. For some of the recordings there is also an e ect of specimen drift during recording.Another e ect is the contamination layer and the(aluminium)oxide layer on the surface of the particle which primarily contains Al.The EDS experiments could therefore not rule out that some Al is contained in the precipitate.As a standard for determining the K-ratios a mineral forsterite was used whose mainANDERSEN et al.:Al±Mg±Si ALLOY 3286components are MgO and SiO 2with a composition so that the Mg/Si atomic ratio is 2.Not taking into account the possible systematic deviations,the EDS experiments indicated that the atomic ratio for Mg/Si was close to or even below 1.The accuracy of these measurements were on the order of 10%.However,they ruled out the earlier accepted ratio of 2for the b 0phase.EDS measurements were also performed on larger particles of the b 'and b -Mg 2Si phases which had been extracted from the alu-minium matrix.These phases gave compositions near the expected,as listed in Table 1.The accuracy here was much better for thin sections since the alu-minium matrix could be avoided entirely.3.3.Exit wave reconstruction3.3.1.The unit cell.Coherency of the b 0phase with the matrix .In Fig.3a reconstructed exit wave (phase)of a b 0particle in the [010]orientation embedded in aluminium is shown.The b 0[010]direction is parallel to a h 100i type aluminium zone axis and is along the needle.Atomic columns in the viewing direction in the image appear as bright dots.The columns in the Al matrix are clearly resolved;in this projection the separation between nearest neighbor columns are 0.2025nm,or half the Al unit cell length.Due to the face centering of alu-minium the nearest neighbor atom columns are also shifted 0.2025nm in the viewing direction relative to each other.In the ®gure circles are drawn that indicate the two di erent height positions of the atoms in the viewing direction.The lattice image of the Al matrix changes over the image due to local variations in tilt.The b 0unit cell is outlined in the particle.Due to the C-centering,the a -axis is twice the apparent periodicity.By calibrating the magni®cation of the image using the aluminium lattice,the unit cell was established to be a =1.51620.002nm,c =0.67420.002nm and b H 105±1068.HREM of other nee-dles lying in the normal direction (Fig.2)have shown that there is a full coherence between the crystal along the b -axis with the same periodicity as the aluminium matrix;therefore b =0.405nm.In the re®nement of di raction images for this zone axis,the monoclinic angle is calculated.It was found to have a mean value b =105.320.58when averaged over 7di raction patterns.The b 0unit cell is closely related to the alu-minium lattice.From di raction patterns (Fig.5)asFig.1.A typical low magni®cation micrograph of b 0needles in a h 001i Al zone axis.Needles are directed along the three h 100i Al directions and appear therefore point-like (dark spots)in the viewing direction.The needles have a mean diameter of about 4nm,and an average length about 50nm.Alarger b 'rod (white appearance)is directed in the viewing direction in the centre of the image.ANDERSEN et al.:Al±Mg±Si ALLOY 3287well as from the exit wave (Fig.3)the following relationship between the phases can be found; 001 Al k 010 b 0,"310 Al k 001 b 0,230 Al k 100 b 0This relationship is the same as found earlier byEdwards et al.[7].A corresponding super cell in aluminium can be de®ned by real vectors ~ab 0 2~a Al 3~b Al ,~b b 0~c Al ,~c b 0 À32~a Al 12~b Alwith respective lengths 1.46,0.405and 0.64nm witha monoclinic angle of 105.38.Half of this super cellis outlined in Fig.3on the left side of the b 0par-ticle.The super cell is also C-centred monoclinicsince two neighbor corners of the half cell along ~ab 0fall on Al atoms in di erent layers.The unit cell for b 0is slightly larger than this Al super cell;3.8%along ~ab 0and 5.3%along ~c b 0.The half super cell (asymmetric unit)contains 11Al atoms.The coherency between b 0and aluminium aids in quantifying the shift of the stacking fault (sf)in the particle that is indicated in Fig.3;By using the Al matrix as reference it can be veri®ed that Al atoms at the left interface,at the upper part (e.g.near the white corners of the unit cell of b 0)are at a di er-ent height relative to similar atoms of b 0on the lower part (here with a black ®ll){.This is illus-trated by the two outlined (half)super cells in the Al matrix that are related to the unit cell of b 0in the upper and lower part of the particle.These super cells are shifted a vector a Al [101]/2relative to each other,which indicates that the shift across the stacking fault in the particle is nearly the same.This shift vector is a Burgers vector of the most common dislocation in aluminium.A model of the fault is given in Section5.Fig.2.Ordinary HREM image of b 0-needle in an h 001i zone axis in Al.The c -axis of the needle is in the plane,and the coherency with h 100i Al in the needle direction is evident.As expected,there is no exact zone axis of b 0along the viewing direction h 001i Al zone axis.The left part of the picture was fourier ®ltered;A high pass ®lter was applied to the upper part and a low pass ®lter to the lower partto extract the periodic information from Al (upper)and the b 0-phase (lower)only.{Alternatively,assume the corners of the outlined unit cells of b 0on each side of the stacking fault to be at thesame heights along ~cb 0.The atoms to the left of Ðand in the matrix outside Ðthese corners must then necessarily have similar heights,since the atomic con®guration and distances to the left of these corners are similar,whether above or below the stacking fault.This assumption must be wrong;When keeping track of the atomic columns in the matrix it leads to the conclusion of an Al atom being at two heights at the same time.Therefore,the corners ofthe unit cells along ~cb 0have di erent heights across the stacking fault.ANDERSEN et al.:Al±Mg±Si ALLOY3288In Fig.4the coherency between the two phases can be studied in more detail.This image is a Fast Fourier Transformation (FFT)of part of Fig.3.Only the lower part of the b 0precipitate is included to reduce streaking caused by the stacking fault.After applying a Fourier ®lter (selecting the con-tents inside the circles superposed on the FFT of Fig.4)the Al re¯ections plus the 610,610,403and 403re¯ections of b 0contribute to the image in Fig.5.The white arrows indicate interface dislo-cations between the particle and matrix.For example,the b 0(601)lattice planes with a spacing d 601=0.211nm are parallel with the Al (200)planes with a spacing of 0.203nm.Therefore,one interface dislocation is expected for each 25Al d 200spacings (normal to the [100]axis in the ®gure).Similarly,for the 403planes,for each 20Al d 020spacing one expects an interface dislocation.The spacings between dislocations observed in Fig.5are di erent from the theoretical ones.The reason for this devi-ation is probably variation in local strain in the particle caused by the stacking fault.Although the exact dislocation is not clear in the image,a matrix dislocation found (marked ``d '')also complicates the situation concerning the mis®t dislocations.This dislocation is found to have a Burgers vector b =0.5a Al [101],as was found when a Burgers vec-tor loop was performed around the particle.This is indicated by the open arrow (d).In Fig.6,two ex-perimental di raction images from the [010]and [001]zone axes are shown.The b 0610and 403re¯ections that coincide with the 200and 020Al matrix re¯ections can also be seen in Fig.6(a).In Fig.6(b)the perfect coherency relation of the (010)lattice planes of the b 0phases with (200)lattice planes can be seen from the overlap of the respect-ive di raction spots.3.3.2.Extraction of the atomic coordinates for b 0from the exit wave images .Figure 7(a)is an increased magni®cation of part of Fig.3.Here the atomic columns are represented as white dots.From this image the atomic positions were esti-mated using the following assumptions:(1)The number of atoms in the unit cell is 22,just as the number of atoms in the similar super cell in aluminium.The number ®ts the apparentnumberFig.3.Phase of an reconstructed exit wave of a typical b 0needle in Al is shown.The needle is viewed head-on along its [010]axis,and along an Al h 001i zone axis.Atomic columns appear white.The b 0unit cell and half the corresponding super cell in Al are outlined.Similarly ®lled circles in the matrix or in the precipitate are atoms (Al or Mg)at the same height.A stacking fault (sf)is indicated.The shiftacross the stacking fault can be determined to be a Al [101]/2.ANDERSEN et al.:Al±Mg±Si ALLOY 3289。
单晶材料的制备High Pressure ResearchVol. 24 No. 4 December 2004 pp. 481 – 490 PREPARATION AND SINGLE-CRYSTAL STRUCTURE OF A NEW HIGH-PRESSURE MODIFICATION OF BaAl2Si2 SHOJI YAMANAKA MASUO KAJIYAMA SADASIVAN N. SIVAKUMAR and HIROSHI FUKUOKA Department of Applied Chemistry Graduate School of Engineering Hiroshima University Higashi-Hiroshima739-8527 JapanA ternary element mixture of Ba Al and Si in a molar ratio of 1 : 2 : 2 was arc-melted and treated under a high-pressure and high-temperature condition of 5 GPa at 1200 8C. X-ray structural analysis was performed on thesingle crystal obtained by this treatment. The crystal was found to be a new high-pressure modication ofBaAl2Si2 and isotypic with layer structured ThCr2Si2 in the space group I4/mmm. The crystal obtained by thesimple arc-melting also had the same structure high-pressure phase. The low-pressure phase a-BaAl2Si2 wasprepared by annealing the arc-melted sample at 1200– 1000 8C. The single crystals of the a-phase werealso obtained which crystallized in the space group Cmcm. This structure was closely related to the structure ofa-BaAl2Ge2 space group Pnma. It is interesting to note that BaAl2Si2 has a pressure induced polymorphwhereas BaAl2Ge2 has a temperature dependent dimorphism.Keywords: Silicide High pressure Synthesis ClathrateBaAl2Si2 Phase transitionINTRODUCTIONIn a series of studies on the synthesis of new silicon clathrate compounds containing bariumandiodine we found that the use of high-pressure and high-temperature HPHT conditionshas been effective and essential. The type I clathrateBa82dSi46 can be prepared under apressure .3 GPa at 800 8C 1 – 3. A new binary clathrate Ba24Si100 was obtained under apressure 1.5 GPa 4.A type I clathrate containing iodine I8Si44I2 was prepared for therst time under a pressure of 5 GPa at temperatures 800 – 900 8C 5. The Ba containingtype I silicon clathrate compounds became superconductors with a transition temperatureTc 4– 8 K 3 6. This is the rst superconductor having a Si-sp3 3D three-dimensionalnetwork. Note that the corresponding germanium analogs are known such as Ba8Ge437 8 and Ba24Ge100 9 – 11 which can be prepared under the ambient pressure by asimple melting. The iodine containing germanium clathrate Ge462x I8x x 8/3 was pre-pared by the decomposition of GeI2 in Xe atmosphere 12. It is also well known thatalkaline-earth metal containing Zintl disilicides MSi2 M Ca Sr and Ba have pressure Corresponding author. Tel./Fax:81-82-424-7740 E-mail: syamanahiroshima-u.ac.jpISSN 0895-7959 print ISSN 1477-2299 online 2004 Taylor amp Francis LtdDOI:10.1080/08957950412331331763482 S. YAMANAKA et al.sensitive silicon networks and undergo pressure induced structural phase transitions 13 –15.Recently it was shown that CaSi2 was transformed into MgB2 type layered structure andshowed a superconducting transition of as high as 14 K under a pressure of 16 GPa 16. Inthis study we havedeveloped a new ternary clathrate system Ba – Al– Si and found a newhigh-pressure modication of BaAl2Si2. The structural transition will be discussed incomparison with the germanium analog BaAl2Ge2 which shows a temperature-dependentstructural transition17.EXPERIMENTALMaterialsBaAl2Si2 was rst prepared from the stoichiometric element mixture of Ba99 KatayamaChemicals Al99.999 Katayama Chemicals and Si99.999 Furu-uchi Chemicals byarc-melting in a water-cooled Cu crucible in Ar atmosphere. The oxidized layer of Ba metalwas removed in an Ar-lled glove box mBraun prior to thearc-melting. The as-meltedsample was ground in the glove box and treated under HPHT conditions using a cubicmultianvil type press Riken model CP-10. The sample was contained in an h-BN cell5 mm in inner diameter and 5 mm in depth which was placed in a carbon tube heater.The sample assembly was set in a pyrophyllite cube 20 20 20 mm3 as a pressuremedium. The reaction temperature was monitored by a thermo-couple placed under theh-BN cell. The details of the sample assembly were shown elsewhere 2. The typical press-ing and heating modes were the following: the sample was rst compressed to 5 GPa andheated to 1200 8C in 1 h and then kept for 1 h at the temperature followed by cooling to700 8C in 2 h. The sample was further cooled down to room temperature in a fewminutes. The applied pressure was gradually released overnight. The separate arc-meltedsamples wereannealed in an h-BN cell vacuum-sealed in a quartz glass tube. The tubewas kept in a furnace at 1200 8C for 1 day and cooled down to 800 8C for 2 days followedby cooling to room temperature for 2days.CharacterizationPowder X-ray diffraction XRD patterns were measured using graphite-monochromated CuKa radiation. X-ray single crystal structural analysis was carried out using a Rigaku RAXISdiffractometer with an imaging plate IP area detector and graphite-monochromated Mo Karadiation. The structure was solved by direct methods and rened with the program SHELX97 18 and WinGX software package 19. Further crystallographic details are given inTable I. The positional the equivalent isotropic and anisotroic displacement parametersare summarized in Table II. Differential thermal analysis DTA was made on the powdersample using an h-BN cell which was sealed in a thin quartz glass tube to protect thesample from oxidation in air. The sealed sample was heated and then cooled down at arate of 10 8C/min using a Shimazu DTA apparatus TA-50WS.RESULTS AND DISCUSSIONArc-MeltingThe powder XRD data of the arc-melted sample of the ternary mixture of BaAl2Si2 is shownin Figure 1a. The pattern could be indexed on a tetragonal unit cell of a 4.1992 andHIGH-PRESSURE MODIFICATION OF BaAl2Si2 483 TABLE I Crystallographic data for a- and b-BaAl2Si2. a-Phase low-pressureb-Phase high-pressureFormula BaAl2Si2 BaAl2Si2Formula weight247.46 247.46Crystal size mm 0.047 0.068 0.13 0.16 0.14 0.025Space group Cmcm no. 63 I4/mmm no. 139a A 4.2385 4.2312b A 10.89054.2312c A 10.1065 12.6019V A3 Z 466.46 4 225.64 2dcalcd g/cm3 3.524 3.644lMo Ka A 0.71069 0.71069m mm21 9.200 9.5122umax8 54.8 54.8Total reections 3315 2739Unique reections 319 101Reections with I 2sI 283 100Number of variables 18 9GOF on F2 0 1.169 1.127R1/wR2I 2sI 0.0266/0.0463 0.0154/0.0367R1/wR2 all data 0.0305/0.04670.0155/0.0367c 12.8736 A. This crystal was different from the BaAl2Si2 prepared by Carrillo-Cabreraet al. 20 using a glassy carbon crucible. This crystal is presumably isotypic with theThCr2Si2 structure 21 a new modication of BaAl2Si2.HPHT TreatmentThe arc-melted sample was treated in the h-BN cell under HPHT conditions. Figure 1c showsthe XRD pattern of the sample obtained by the treatment at 5 GPa and 1200 8C. The detailedcondition was described in Experimental section. The XRD pattern of the HPHT-treatedsample could be indexed on a similar tetragonal cell with a 4.2315 andc 12.6015 A. Although the lattice constant c was slightly decreased from 12.873 A ofthe as-arc-melted sample it was apparent that the structure was essentially unchanged bythe HPHT treatment.Annealing the CrystalsThe HPHT-treated samples were annealed in h-BN cells vacuum-sealed in quartz glass tubeat 800 – 1200 8C. Figure 1b shows the XRD pattern of the sample obtained after annealing.TABLE II Atomic coordinates equivalent isotropic andanisotropic temperature factors A2 for a- andb-BaAl2Si2. Site x y z U11 U22 U33 U23 U13 U12 Ueqa-BaAl2Si2 Low-pressure phase space group CmcmBa 4c 0 0.07766 0.2500 0.01283 0.00973 0.01593 0 0 0 0.01282Al 8f 0 0.38883 0.03262 0.00739 0.0592 0.019311 20.023911 0 0 0.02857Si 8f 0 0.79421 0.12443 0.013710 0.010611 0.078619 20.010111 0 00.03436b-BaAl2Si2 High-pressure phase space group I4/mmmBa 2a 0 0 0 0.02163 0.02163 0.02865 0 0 0 0.02393Al 4d 1/2 0 1/4 0.015860.01586 0.039113 0 0 0 0.02365Si 4e 1/2 1/2 0.13612 0.01606 0.01606 0.042413 0 0 0 0.02485Note: Ueq is dened as one-third of the trace of the orthogonalized U tensor.484 S. YAMANAKA et al.FIGURE 1 Powder XRD patterns of BaAl2Si2 prepared in different conditions: a arc-melted b annealed at1200 8C and c HPHT treated.The pattern was changed to that of an orthorhombic symmetry of a 4.2385b 10.8905 and c 10.1065 A. Single crystals were obtained by annealing from atemperature of 1200 8C and were used for the structural analysis.DTA AnalysisFigure 2 shows the DTA curves measured on the crystals obtained by the HPHT treatmentand the annealing at 1200 8C. The annealed sample shows a sharp endothermic peak due tothe congruent melting of the sample at 1027 8C and an exothermic peak at 1017 8C due to thecrystallization on the cooling process. The HPHT sample also shows similar sharp endother-mic and exothermic peaks coupled with a broad endothermic peak starting from about500 8C. After melting the HPHT-treated sampledid not show the broad endothermicpeak in the second measurement.Single Crystal AnalysisThe two types of single crystals the HPHT-treated sample high-pressure phase orb-BaAl2Si2 and the annealed sample low-pressure phase or a-BaAl2Si2 were performedand the results are shown in Tables I and II. The high-pressure phase crystallized in the spacegroup I4/mmm isotypic with the popular crystal system of the ThCr2Si2 structure 21. Thisis isotypic with thehigh-temperture phase of b-BaAl2Ge2 reported by Leoni et al. 17. Theannealed or low-pressure phase crystallized in the space group Cmcm. This is isotypic withthe low-temperature phase of a-BaAl2Ge2 space group Pnma. The space group Cmcmfor a-BaAl2Si2 is a minimalnon-isomorphic supergroup of Pnma for a-BaAl2Ge2 22.The Si and Al sites cannot be distinguished by x-ray. The Si and Al sites of BaAl2Si2 HIGH-PRESSURE MODIFICATION OF BaAl2Si2 485 FIGURE 2 DTA curves of a annealed and b HPHT-treated samples.were tentatively assigned to the Ge and Al sites of BaAl2Ge2 respectively. Some typicalinteratomic lengths and bond angles are given in TableIII.Structural Details and TransitionsThe germanide analog BaAl2Ge2 has been studied by Leoni et al. 17. They found thatthe germanide shows a temperature dependent dimorphism the 3D network ofthelow-temperature a-phase the a-BaCu2Si2 structure 23 space group Pnma transformsinto the layer structured high-temperature b-phase theThCr2Si2 structure space groupI4/mmm. The transformation occurs reversibly at 1100 K and the crystal meltsincongruently at 1310 K. Similar dimorphisms were found in BaCu2S2 and BaCu2Se223 24. It is interesting to note that the b-phase of BaAl2Si2 in this study was obtainedas a high-pressure phase which is transformed into the a-phase by annealing at elevated486 S. YAMANAKA et al. TABLE III Main interatomic distances d and bond angles for a- and b-BaAl2Si2.a-BaAl2Si2 b-BaAl2Si2 Distances d A Distances d A Ba222Si 3.3182 Ba228Si 3.4483 Ba224Si 3.4303 Ba228Al 3.7951 Ba224Si 4.0402Ba222Si 4.5911 Ba224Al 3.5773 Ba224Al 3.6692 Ba222Al 4.0562 2Si Si2 2.5384 2Si Si2 3.4333 2Al Al2 2.5103 2Al Al2 2.9911 2Al Si22.5322 2Al Si2 2.5571 2.5483 Angles 8 Angles 8 2Si2 Al2 2Al 113.6110 2Si2 Al2 2Al 111.679 95.159 71.624 2Al2 Si2 2Si 113.6110 2Al2 Si22Si 111.676 84.859 108.383 119.247 126.2811temperatures. It is reasonable to consider that the a-phase of BaAl2Si2 should becharacterized as a low-pressure stable phase i.e. the dimorphism of BaAl2Si2 is pressuredependent. Note that the high-pressure phase of BaAl2Si2 was also obtained by arc-melting in the ambient pressure. This can be interpreted as follows: in the arc-melting themelted sample was rapidly cooled and quenched to room temperature and the surface ofthe melt was rst solidied into a hard crust. The melt inside the crust will bethencooled. If the sample volume of the melt increases upon the crystallization.。
材料科学基础专业词汇:第一章晶体结构原子质量单位Atomic mass unit (amu) 原子数Atomic number原子量Atomic weight 波尔原子模型Bohr atomic model键能Bonding energy 库仑力Coulombic force共价键Covalent bond 分子的构型molecular configuration 电子构型electronic configuration 负电的Electronegative正电的Electropositive 基态Ground state氢键Hydrogen bond 离子键Ionic bond同位素Isotope 金属键Metallic bond摩尔Mole泡利不相容原理 Pauli exclusion principle 元素周期表Periodic table原子atom 分子molecule分子量molecule weight 极性分子Polar molecule量子数quantum number 价电子valence electron范德华键van der waals bond 电子轨道electron orbitals点群point group 对称要素symmetry elements各向异性anisotropy 原子堆积因数Atomic packing factor(APF)体心立方结构body-centered cubic (BCC) 面心立方结构face-centered cubic (FCC) 布拉格定律bragg’s law 配位数coordination number晶体结构crystal structure 晶系crystal system晶体的crystalline 衍射diffraction中子衍射neutron diffraction 电子衍射electron diffraction晶界grain boundary 六方密堆积hexagonal close-packed(HCP)鲍林规则Pauling’s rules NaCl型结构NaCl-type structure CsCl型结构Caesium Chloride structure 闪锌矿型结构Blende-type structure纤锌矿型结构Wurtzite structure 金红石型结构Rutile structure萤石型结构Fluorite structure 钙钛矿型结构Perovskite-type structure 尖晶石型结构Spinel-type structure 硅酸盐结构Structure of silicates岛状结构Island structure 链状结构Chain structure层状结构Layer structure 架状结构Framework structure滑石talc 叶蜡石pyrophyllite高岭石kaolinite 石英quartz长石feldspar 美橄榄石forsterite各向同性的isotropic 各向异性的anisotropy晶格lattice 晶格参数lattice parameters密勒指数miller indices 非结晶的noncrystalline多晶的polycrystalline 多晶形polymorphism单晶single crystal 晶胞unit cell电位electron states (化合)价valence电子electrons 共价键covalent bonding金属键metallic bonding 离子键Ionic bonding极性分子polar molecules 原子面密度atomic planar density衍射角diffraction angle 合金alloy粒度,晶粒大小grain size 显微结构microstructure显微照相photomicrograph 扫描电子显微镜scanning electronmicroscope (SEM)重量百分数weight percent 透射电子显微镜 transmission electronmicroscope (TEM)四方的tetragonal 单斜的monoclinic配位数coordination number材料科学基础专业词汇:第二章晶体结构缺陷缺陷defect, imperfection 点缺陷point defect线缺陷line defect, dislocation 面缺陷interface defect体缺陷volume defect 位错排列dislocation arrangement位错线dislocation line 刃位错edge dislocation螺位错screw dislocation 混合位错mixed dislocation晶界grain boundaries 大角度晶界high-angle grainboundaries 小角度晶界tilt boundary, 孪晶界twin boundaries位错阵列dislocation array 位错气团dislocation atmosphere位错轴dislocation axis 位错胞dislocation cell位错爬移dislocation climb 位错聚结dislocation coalescence位错滑移dislocation slip 位错核心能量dislocation core energy位错裂纹dislocation crack 位错阻尼dislocation damping位错密度dislocation density 原子错位substitution of a wrongatom间隙原子interstitial atom 晶格空位vacant lattice sites间隙位置interstitial sites 杂质impurities弗伦克尔缺陷Frenkel disorder 肖脱基缺陷Schottky disorder主晶相the host lattice 错位原子misplaced atoms缔合中心Associated Centers. 自由电子Free Electrons电子空穴Electron Holes 伯格斯矢量Burgers克罗各-明克符号K roger Vink notation 中性原子neutral atom材料科学基础专业词汇:第二章晶体结构缺陷-固溶体固溶体solid solution 固溶度solid solubility化合物compound 间隙固溶体interstitial solid solution置换固溶体substitutional solid solution 金属间化合物intermetallics不混溶固溶体immiscible solid solution 转熔型固溶体peritectic solid solution有序固溶体ordered solid solution 无序固溶体disordered solid solution 固溶强化solid solution strengthening 取代型固溶体Substitutional solidsolutions过饱和固溶体supersaturated solid solution 非化学计量化合物Nonstoichiometric compound材料科学基础专业词汇:第三章熔体结构熔体结构structure of melt 过冷液体supercooling melt玻璃态vitreous state 软化温度softening temperature粘度viscosity 表面张力Surface tension介稳态过渡相metastable phase 组织constitution淬火quenching 退火的softened玻璃分相phase separation in glasses 体积收缩volume shrinkage材料科学基础专业词汇:第四章固体的表面与界面表面surface 界面interface同相界面homophase boundary 异相界面heterophase boundary晶界grain boundary 表面能surface energy小角度晶界low angle grain boundary 大角度晶界high angle grain boundary 共格孪晶界coherent twin boundary 晶界迁移grain boundary migration 错配度mismatch 驰豫relaxation重构reconstuction 表面吸附surface adsorption表面能surface energy 倾转晶界titlt grain boundary扭转晶界twist grain boundary 倒易密度reciprocal density共格界面coherent boundary 半共格界面semi-coherent boundary 非共格界面noncoherent boundary 界面能interfacial free energy应变能strain energy 晶体学取向关系crystallographicorientation惯习面habit plane材料科学基础专业词汇:第五章相图相图phase diagrams 相phase组分component 组元compoonent相律Phase rule 投影图Projection drawing浓度三角形Concentration triangle 冷却曲线Cooling curve成分composition 自由度freedom相平衡phase equilibrium 化学势chemical potential热力学thermodynamics 相律phase rule吉布斯相律Gibbs phase rule 自由能free energy吉布斯自由能Gibbs free energy 吉布斯混合能Gibbs energy of mixing 吉布斯熵Gibbs entropy 吉布斯函数Gibbs function热力学函数thermodynamics function 热分析thermal analysis过冷supercooling 过冷度degree of supercooling杠杆定律lever rule 相界phase boundary相界线phase boundary line 相界交联phase boundarycrosslinking共轭线conjugate lines 相界有限交联phase boundarycrosslinking相界反应phase boundary reaction 相变phase change相组成phase composition 共格相phase-coherent金相相组织phase constentuent 相衬phase contrast相衬显微镜phase contrast microscope 相衬显微术phase contrastmicroscopy相分布phase distribution 相平衡常数phase equilibriumconstant相平衡图phase equilibrium diagram 相变滞后phase transition lag相分离phase segregation 相序phase order相稳定性phase stability 相态phase state相稳定区phase stabile range 相变温度phase transitiontemperature相变压力phase transition pressure 同质多晶转变polymorphictransformation同素异晶转变allotropic transformation 相平衡条件phase equilibriumconditions显微结构microstructures 低共熔体eutectoid不混溶性immiscibility材料科学基础专业词汇:第六章扩散活化能activation energy扩散通量diffusion flux浓度梯度concentration gradient菲克第一定律Fick’s first law菲克第二定律Fick’s second law相关因子correlation factor稳态扩散steady state diffusion非稳态扩散nonsteady-state diffusion 扩散系数diffusion coefficient跳动几率jump frequency填隙机制interstitalcy mechanism晶界扩散grain boundary diffusion 短路扩散short-circuit diffusion上坡扩散uphill diffusion下坡扩散Downhill diffusion互扩散系数Mutual diffusion渗碳剂carburizing浓度梯度concentration gradient 浓度分布曲线concentration profile扩散流量diffusion flux驱动力driving force间隙扩散interstitial diffusion自扩散self-diffusion表面扩散surface diffusion空位扩散vacancy diffusion扩散偶diffusion couple扩散方程diffusion equation扩散机理diffusion mechanism扩散特性diffusion property无规行走Random walk达肯方程Dark equation柯肯达尔效应Kirkendall equation本征热缺陷Intrinsic thermal defect本征扩散系数Intrinsic diffusion coefficient离子电导率Ion-conductivity空位机制Vacancy concentration材料科学基础专业词汇:第七章相变过冷supercooling 过冷度degree of supercooling 晶核nucleus 形核nucleation形核功nucleation energy 晶体长大crystal growth均匀形核homogeneous nucleation 非均匀形核heterogeneous nucleation形核率nucleation rate 长大速率growth rate 热力学函数thermodynamics function临界晶核critical nucleus 临界晶核半径critical nucleus radius枝晶偏析dendritic segregation 局部平衡localized equilibrium平衡分配系数equilibriumdistributioncoefficient有效分配系数effective distribution coefficient成分过冷constitutional supercooling 引领(领先)相leading phase共晶组织eutectic structure 层状共晶体lamellar eutectic伪共晶pseudoeutectic 离异共晶divorsed eutectic表面等轴晶区chill zone 柱状晶区columnar zone中心等轴晶区equiaxed crystal zone 定向凝固unidirectional solidification 急冷技术splatcooling 区域提纯zone refining单晶提拉法Czochralski method 晶界形核boundary nucleation位错形核dislocation nucleation 晶核长大nuclei growth斯宾那多分解spinodal decomposition有序无序转变disordered-order transition马氏体相变martensite phase transformation 马氏体martensite材料科学基础专业词汇:第八、九章固相反应和烧结固相反应solid state reaction 烧结sintering烧成fire 合金alloy再结晶Recrystallization 二次再结晶Secondary recrystallization 成核nucleation 结晶crystallization子晶,雏晶matted crystal 耔晶取向seed orientation异质核化heterogeneous nucleation 均匀化热处理homogenization heattreatment铁碳合金iron-carbon alloy 渗碳体cementite铁素体ferrite 奥氏体austenite共晶反应eutectic reaction 固溶处理solution heat treatment。
常见材料学专业名词中英文对译材料科学 Material Science材料科学定义Material Science Definition加工性能 Machinability强度 Strength抗腐蚀及耐用Corrosion & resistance durability 金属特性Special metallic features抗敏感及环境保护Allergic, re-cycling & environmental protection化学元素 Chemical element元素的原子序数Atom of Elements原子及固体物质Atom and solid material原子的组成、大小、体积和单位图表The size, mass, charge of an atom, and is particles (Pronton,Nentron and Electron)原子的组织图 Atom Constitutes周期表 Periodic Table 原子键结 Atom Bonding金属与合金 Metal and Alloy铁及非铁金属Ferrous & Non Ferrous Metal金属的特性 Features of Metal晶体结构 Crystal Pattern晶体结构,定向格子及单位晶格Crystal structure, Space lattice & Unit cellX线结晶分析法X – ray crystal analyics method金属结晶格子 Metal space lattice格子常数 Lattice constant米勒指数 Mill's Index金相及相律 Metal Phase and Phase Rule固熔体 Solid solution置换型固熔体 Substitutional type solid solution插入型固熔体 Interstital solid solution金属间化物 Intermetallic compound 金属变态 Transformation变态点 Transformation Point磁性变态 Magnetic Transformation 同素变态 Allotropic Transformation合金平衡状态 Thermal Equilibrium 相律 Phase Rule自由度 Degree of freedom临界温度 Critical temperture共晶 Eutectic包晶温度 Peritectic Temperature包晶反应 Peritectic Reaction包晶合金 Peritectic Alloy亚共晶体 Hypoeutetic Alloy过共晶体 Hyper-ectectic Alloy金属塑性 Plastic Deformation滑动面 Slip Plan畸变 Distortion硬化 Work Hardening退火 Annealing回复柔软 Crystal Recovery再结晶 Recrystallization金属材料的性能及试验Properties & testing of metal化学性能 Chemical Properties物理性能 Physical Properties 颜色 Colour磁性 Magnetisum比电阻Specific resistivity & specific resistance比重Specific gravity & specific density 比热 Specific Heat热膨胀系数Coefficient of thermal expansion 导热度 Heat conductivity机械性能 Mechanical properties屈服强度Yield strength伸长度 Elongation断面缩率 Reduction of area金属材料的试验方法The Method of Metal inspection不破坏检验Non – destructive inspections渗透探伤法 Penetrate inspection 磁粉探伤法Magnetic particle inspection放射线探伤法 Radiographic inspection超声波探伤法 Ultrasonic inspection 显微观察法 Microscopicinspection破坏的检验 DestructiveInspection冲击测试 Impact Test疲劳测试 Fatigue Test潜变测试 Creep Test潜变强度 Creeps Strength第壹潜变期 Primary Creep主要金属元素之物理性质Physical properties of major Metal Elements转变元素 Transition element交换能量 Positive energy exchange外价电子 Outer valence electrons化学结合 Chemical bond钢铁的主要成份The major element of steel钢铁用"碳"之含量来分类Classification of Steel according to Carbon contents 铁相 Steel Phases钢铁的名称 Name of steel纯铁体 Ferrite渗碳体 Cementitle奥氏体 Austenite珠光体及共释钢 Pearlite &Eutectoid 奥氏体碳钢 Austenite Carbon Steel 单相金属 Single Phase Metal共释变态 Eutectoid Transformation珠光体 Pearlite过共释钢 Hype-eutectoid珠光体 Pearlite粗珠光体 Coarse pearlite中珠光体 Medium pearlite幼珠光体 Fine pearlite磁性变态点 Magnetic Transformation 钢铁的制造 Manufacturing of Steel 连续铸造法 Continuous casting process电炉 Electric furnace钢铁生产流程 Steel Production Flow Chart钢材的熔铸、锻造、挤压及延轧The Casting, Fogging, Extrusion, Rolling & Steel熔铸 Casting锻造 Fogging挤压 Extrusion延轧 Rolling冲剪 Drawing & stamping特殊钢 Special Steel简介 General特殊钢以原素分类Classification of Special Steel according to Element特殊钢以用途来分类Classification of Special Steel according to End UsageSulphuric Free Cutting Steel硬化性能 Hardenability钢的脆性 Brittleness of Steel 低温脆性 Cold brittleness回火脆性 Temper brittleness 材料的加工性能 Drawing abillity 硬度 Hardness表面处理 Surface finish End usages, industrial standard, quality, condition and hardness of cold rolled steel strip硬度及拉力 Hardness & Tensile strength test拉伸测试(顺纹测试) Elongation test 曲面(假曲率) Camber防止生锈 Rust Protection生锈速度表 Speed of rusting焊接 Welding气焊 Gas Welding埋弧焊 Submerged-arc Welding电阻焊 Resistance Welding电解/电镀锌大大增强钢片的防锈能力Galvanic Action improving Weather & Corrosion Resistance of the Base Steel Sheet上漆能力 Paint Adhesion电镀锌钢片的焊接Welding of Electro-galvanized steel sheet点焊 Spot welding滚焊 Seam welding电镀锌(电解)钢片Electro-galvanized Steel Sheet生产流程 Production Flow Chart锌镀层质量 Zinc Coating Mass表面处理 Surface Treatment冷轧钢片 Cold-Rolled SteelSheet/Strip热轧钢片 Hot-Rolled Sheet/Strip电解冷轧钢片厚度公差Thickness Tolerance of Electrolytic Cold-rolled sheet热轧钢片厚度公差Thickness Tolerance of Hot-rolled sheet冷轧或热轧钢片阔度公差 Width Tolerance of Cold or Hot-rolled sheet 长度公差 Length Tolerance理论质量 Theoretical Mass简介 General硬度 Hardness钢的种类 Type of Steel表面处理 Surface Finish常用尺寸 Commonly Used Size 电器用硅 [硅] 钢片 Electrical Steel Sheet软磁材料 Soft Magnetic Material硬磁材料 Hard Magnetic Material最大能量积 Maximum Energy Product 晶粒取向(Grain-Oriented)及非晶粒取向(Non-Oriented)Grain Oriented & Non-Oriented电器用硅 [硅] 钢片的最终用途及规格End Usage and Designations of Electrical Steel Strip电器用的硅 [硅] 钢片之分类Classification of Silicon Steel Sheet for Electrical Use电器用钢片的绝缘涂层Performance of Surface Insulation of Electrical Steel Sheets退火Annealing电器用钢片用家需自行应力退火原因Annealing of the Electrical Steel Sheet退火时注意事项 Annealing Precautionary提防过份氧化 No Excessive Oxidation应力退火温度Stress –relieving Annealing Temperature绝缘表面 Surface Insulation镀铝硅合金钢片的特色Feature of Aluminized Silicon Alloy Steel Sheet用途 End Usages抗化学品能力 Chemical Resistance 公差 Size Tolerance焊接能力 Weldability钢板 Steel Plate钢板用途分类及各国钢板的工业标准包括日工标准及美材试标准Type of steel Plate & Related JIS, ASTM and Other Major Industrial Standards钢板生产流程 Production Flow Chart 钢板订货需知 Ordering of Steel Plate不锈钢 Stainless Steel不锈钢的定义Definition of Stainless Steel不锈钢之分类,耐腐蚀性及耐热性Classification, Corrosion Resistant & Heat Resistance of Stainless Steel 铁铬系不锈钢片Chrome Stainless Steel表面处理 Surface finish不锈钢片机械性能(301, 304, 631, CSP) Mechanical Properties of Spring use Stainless Steel不锈钢–种类,工业标准,化学成份,特点及主要用途Stainless Steel – Type, Industrial Standard, Chemical Composition, Characteristic & end usage of the most commonly used Stainless Steel 不锈钢薄片用途例End Usage of Thinner Gauge不锈钢片、板用途例Examples of End Usages of Strip, Sheet & Plate不锈钢应力退火卷片常用规格名词图解General Specification of Tension Annealed Stainless Steel Strips耐热不锈钢Heat-Resistance Stainless Steel 镍铬系耐热不锈钢特性、化学成份、及操作温度Heat-Resistance Stainless Steel 铬系耐热钢Chrome Heat Resistance Steel镍铬耐热钢Ni - Cr Heat Resistance Steel超耐热钢Special Heat Resistance Steel抗热超级合金Heat Resistance Super Alloy边缘处理 Edge Finish硬度 Hardness高碳钢化学成份及用途高碳钢片 High Carbon Steel Strip 分类 Classification用组织结构分类 Classification According to Grain Structure用含碳量分类–即低碳钢、中碳钢及高碳钢 Classification According to Carbon Contains弹簧用碳钢片CarbonSteel Strip For Spring Use 冷轧状态 Cold Rolled Strip回火状态 Annealed Strip淬火及回火状态Hardened & Tempered Strip/ Precision – Quenched Steel Strip贝氏体钢片 Bainite Steel Strip弹簧用碳钢片材之边缘处理 Edge Finished淬火剂 Quenching Media碳钢回火 Tempering回火有低温回火及高温回火Low & High Temperature Tempering 高温回火High Temperature Tempering退火 Annealing完全退火 Full Annealing扩散退火 Diffusion Annealing低温退火 Low Temperature Annealing 中途退火 Process Annealing球化退火 Spheroidizing Annealing光辉退火 Bright Annealing淬火 Quenching时间淬火 Time Quenching奥氏铁孻回火 Austempering马氏铁体淬火 Marquenching高碳钢片用途 End Usage of High Carbon Steel Strip冷轧高碳钢–日本工业标准Cold-Rolled (Special Steel) Carbon Steel Strip to JIS G3311电镀金属钢片 Plate Metal Strip电镀金属捆片的优点Advantage of Using Plate Metal Strip 金属捆片电镀层Plated Layer of Plated Metal Strip 镀镍 Nickel Plated镀铬 Chrome Plated镀黄铜 Brass Plated基层金属 Base Metal of Plated Metal Strip低碳钢或铁基层金属Iron & Low Carbon as Base Metal不锈钢基层金属 Stainless Steel as Base Metal铜基层金属 Copper as Base Metal 黄铜基层金属 Brass as Base Metal 轴承合金 Bearing Alloy易溶合金 Fusible Alloy化学成份 Chemical Composition机械性能 Mechanical Properties化学成份 Chemical composition Manufacturing Method应用材料 Material Used特点 Characteristic用途 End Usages材料的类型Types of materials, metals, ceramics, polymers, composites, elastomer部分材料性质复习Review of selected properties of materials,电导率和电阻率conductivity and resistivity,热导率thermal conductivity,应力和应变stress and strain,弹性应变elastic strain,塑性应变plastic strain,屈服强度yield strength,最大抗拉强度ultimate tensile strength,最大强度ultimate strength,延展性ductility,伸长率elongation,断面收缩率reduction of area,颈缩necking,断裂强度breaking strength,韧性toughness,硬度hardness,疲劳强度fatigue strength,蜂窝 honeycomb,热脆性 heat shortness,晶胞中的原子数atoms per cell,点阵lattice, 阵点lattice point, 点阵参数lattice parameter,密排六方hexagonal close-packed, 六方晶胞hexagonal unit cell,体心立方body-centered cubic,面心立方face-centered cubic,弥勒指数Miller indices,晶面crystal plane,晶系crystal system,晶向crystal direction,相变机理Phase transformation mechanism: 成核生长相变nucleation–growth transition,斯宾那多分解spinodal decomposition,有序无序转变disordered-order transition,马氏体相变martensite phase transformation,成核nucleation,成核机理nucleation mechanism,成核势垒nucleation barrier,晶核,结晶中心nucleus of crystal, 金属组织的)基体quay,基体,基块,基质,结合剂matrix, 子晶,雏晶matted crystal,耔晶,晶种seed crystal,耔晶取向seed orientation,籽晶生长seeded growth,均质核化homogeneous nucleation, 异质核化heterogeneous nucleation, 均匀化热处理homogenization heat treatment,熟料 grog,自恰场self-consistent field固溶体Solid solution:有序固溶体ordered solid solution, 无序固溶体disordered solid solution,有序合金ordered alloy,无序合金disordered alloy.无序点阵disordered lattice,分散,扩散,弥散dispersal,分散剂dispersant,分散剂,添加剂dispersant additive, 分散剂,弥散剂dispersant agent缺陷defect, imperfection,点缺陷point defect,线缺陷 line defect, dislocation,面缺陷interface defect, surface defect,体缺陷volume defect,位错排列dislocation arrangement, 位错阵列dislocation array,位错气团dislocation atmosphere,位错轴dislocation axis,位错胞dislocation cell,位错爬移dislocation climb, 位错滑移dislocation slip, dislocation movement by slip,位错聚结dislocation coalescence, 位错核心能量dislocation core energy,位错裂纹dislocation crack,位错阻尼dislocation damping,位错密度dislocation density,体积膨胀volume dilation,体积收缩volume shrinkage,回火tempering,退火annealing,退火的,软化的softened,软化退火,软化(处理)softening, 淬火quenching,淬火硬化quenching hardening,正火normalizing, normalization, 退火织构annealing texture,人工时效artificial aging,细长比aspect ratio,形变热处理ausforming,等温退火austempering,奥氏体austenite,奥氏体化austenitizing,贝氏体bainite,马氏体martensite,马氏体淬火marquench,马氏体退火martemper,马氏体时效钢maraging steel,渗碳体cementite,固溶强化solid solution strengthening,钢屑混凝土steel chips concrete,水玻璃,硅酸钠sodium silicate,水玻璃粘结剂sodium silicate binder, 硅酸钠类防水剂sodium silicate waterproofing agent,扩散diffusion,扩散系数diffusivity,相变phase transition,烧结sintering,固相反应solid-phase reaction,相图与相结构phase diagrams and phase structures ,相phase,组分component,自由度freedom,相平衡phase equilibrium, 吉布斯相律Gibbs phase rule,吉布斯自由能Gibbs free energy,吉布斯混合能Gibbs energy of mixing, 吉布斯熵Gibbs entropy,吉布斯函数Gibbs function,相平衡phase balance,相界phase boundary,相界线 phase boundary line,相界交联 phase boundary crosslinking,相界有限交联phase boundary crosslinking,相界反应phase boundary reaction, 相变phase change,相组成phase composition,共格相 phase-coherent,金相相组织 phase constentuent,相分布phase distribution,相平衡常数phase equilibrium constant,相平衡图phase equilibrium diagram, 相分离phase segregation, phase separation,玻璃分相phase separation in glasses,相序phase order, phase sequence, 相稳定性phase stability,相态phase state,相稳定区phase stabile range,相变温度phase transition temperature,相变压力phase transition pressure, 同质多晶转变polymorphic transformation,相平衡条件phase equilibrium conditions,显微结构microstructures,不混溶固溶体immiscible solid solution,转熔型固溶体peritectic solid solution,低共熔体eutectoid,crystallization, 不混溶性immiscibility,固态反应solid state reaction,烧结sintering,相变机理Phase transformation mechanism: 成核生长相变nucleation–growth transition,斯宾那多分解spinodal decomposition,有序无序转变disordered-order transition,马氏体相变martensite phase transformation,成核nucleation,成核机理nucleation mechanism,成核势垒nucleation barrier,晶核,结晶中心nucleus of crystal, (金属组织的)基体quay,基体,基块,基质,结合剂matrix, 子晶,雏晶matted crystal,耔晶,晶种seed crystal,耔晶取向seed orientation,籽晶生长seeded growth,均质核化homogeneous nucleation, 异质核化heterogeneous nucleation, 均匀化热处理homogenization heat treatment。
Hydrothermal Synthesis of Barium Titanate:Effect of Titania Precursor and Calcination Temperature on Phase TransitionNatarajan Sasirekha,Baskaran Rajesh,and Yu-Wen Chen*Department of Chemical Engineering,Nanocatalysis Research Center,National Central Uni V ersity,Chung-Li320,Taiwan,Republic of ChinaNanosized barium titanate powders were synthesized by a hydrothermal method.The effect of titania precursorson the phase transition of BaTiO3with respect to Ba/Ti ratio,reaction temperature,reaction time,and calcinationtemperature was investigated.The synthesized materials were characterized by X-ray diffraction,scanningelectron microscopy,and transmission electron microscopy.BaTiO3in pure cubic phase with sphericalmorphology was observed with a lower calcination temperature,Ba/Ti ratio,reaction temperature,and time.Increase in the tetragonal phase was ascertained in treatments at higher reaction temperature with a longerreaction time.The lattice hydroxyl release is believed to be the reason for tetragonality at high reaction andcalcination temperatures.To prepare tetragonal BaTiO3using HClO4-TiO2,the optimum synthesis conditionsviz.,Ba/Ti ratio,reaction temperature,and reaction time,are1.2,160°C,and3h,respectively,at a calcinationtemperature of1150°C.The reaction time and reaction temperature for the cubic-tetragonal phasetransformation of BaTiO3shifted toward shorter reaction time and lower reaction temperature when TiO2was synthesized by hydrolysis using HClO4as the acid catalyst.1.IntroductionBarium titanate(BaTiO3),one of the most well-known ferroelectrics,has played an important part in the modern ceramic industry since the discovery of ferroelectric properties in the tetragonal phase of BaTiO3during the1940s.1It has been broadly used as a dielectric material in multilayer ceramic capacitors(MLCCs),2-4printed circuit boards(PCBs),5,6dy-namic random access memory(DRAM),positive temperature coefficient of resistance thermistors(PTCRs),piezoelectric sensors for ultrasonic and measuring devices,pressure transduc-ers,infrared detectors,and electrooptic devices7-9due to its unique perovskite structure(ABO3)and exceptionally high dielectric[(2-5)×103]10and piezoelectric properties at room temperature.However,these outstanding behaviors mainly depend on the crystal structure,shape,size,stoichiometry, homogeneity,and surface properties of BaTiO3,which in turn depends on the synthesis method.Among the crystal structures of BaTiO3,the cubic phase exhibits paraelectric properties,while the tetragonal phase shows ferroelectric properties.The direct generation of tetragonal BaTiO3is of considerable interest. The conventional synthesis of barium titanate compounds typically involves high-temperature(∼1200°C)calcinations of a BaCO3and TiO2powder mixture,which often results in low purity and polydispersity due to high reaction temperature and heterogeneous solid-phase reaction.11,12Nevertheless,fine Ba-TiO3ceramics can be prepared by wet-chemistry synthesis techniques,including the coprecipitation method,13coprecipi-tation in combination with the inverse microemulsion method,14,15 sol-gel processing,16,17the hydrothermal method,18-21spray pyrolysis,22the oxalate route,23the high-temperature ceramic route,the microwave hydrothermal method,24-27and the polymeric precursor method.28Hydrothermal synthesis for the preparation of crystalline BaTiO3has gained popularity recently.29-33It involves the chemical reactions of Ba(OH)2,TiO2,or gels of Ba-Ti acetate mixtures at a high temperature.It has the advantage of producing finer particles with more uniform size.In addition,the interac-tion between the solid and fluid phases determines the physical characteristics of BaTiO3,and hence,the synthesis allows one to control the particle size by adjusting the synthesis parameters, such as the reaction temperature,time,and pH values.The synergistic effect of solvent,temperature,and pressure on the ionic reaction equilibrium in the hydrothermal reaction medium can stabilize the formation of BaTiO3and retards the formation of impurities.Also,the precursors for the preparation of BaTiO3 by hydrothermal synthesis are readily available,inexpensive, and easy to handle,which makes the hydrothermal synthesis an easy and effective method to adopt for the synthesis of BaTiO3.Although the hydrothermal synthesis has the above-mentioned advantages,the formation and growth mechanisms in BaTiO3synthesis have not been well understood.There are a few articles about the study of phase transformation of BaTiO3 with preparation conditions.However,so far there is no report about the effect of titania precursor,which plays a vital role in the growth mechanism of BaTiO3synthesis,on the phase transformation of BaTiO3.In this paper,a systematic investiga-tion on the effect of titania precursor on phase transformation of BaTiO3with respect to Ba/Ti ratio,reaction temperature, reaction time,and calcination temperature is presented.2.Experimental Section2.1.Hydrothermal Synthesis of BaTiO3.Barium titanate powders were synthesized by hydrothermal method.All the reagents used were of analytical grade.Hydrothermally produced TiO2particles34prepared using hydrochloric acid and perchloric acid as acid precursors were used as the titania source.The detailed characteristics of these materials have been presented in our previous paper.34Ba(OH)2‚8H2O(Showa Chemical Co., Ltd.)and TiO2powder(rutile)34were mixed with a Ba/Ti ratio (1.2,1.4,1.6,1.8,2.0)in a50mL autoclave with45mL of deionized water.The autoclave was sealed,shaken,and placed in an oven at160°C for a variable reaction period ranging from*To whom correspondence should be addressed.Tel.:(886)3422751,ext34203.Fax:(886)34252296.E-mail:ywchen@cc.ncu.edu.tw.1868Ind.Eng.Chem.Res.2008,47,1868-187510.1021/ie070986m CCC:$40.75©2008American Chemical SocietyPublished on Web02/16/20083to 24h.After cooling naturally to room temperature,the contents of the autoclave were diluted in 90mL of 0.1M formic acid with stirring for 5min in an attempt to remove any BaCO 3formed and the addition of excess Ba 2+to the starting solution.The mixture was filtered and washed with distilled water (500mL)three times,and the residue was dried in oven at 100°C for 24h.2.2.Characterization.The crystalline phase of BaTiO 3was analyzed by powder X-ray diffraction (XRD)using a Siemens D500automatic powder diffractometer.Nickel-filtered Cu K R radiation (λ)0.15418nm)was used with a generator voltage of 40kV and a current of 29mA.Bragg -Brentano focusing geometry was employed with an automatic divergence slit (irradiated sample length was 12.5nm),a receiving slit of 0.1nm,a fixed slit of 4°,and a proportional counter as a detector.It was operated in the step scan mode,at scanning speeds of 0.1°2θ/s and 1s step time in the range 20-80°for barium titanate.Scherrer’s equation 35was used to calculate the crys-tallite size of barium titanate crystals from the full width at half-maximum of the XRD peak.The morphology of the particles was analyzed by scanning electron microscopy (SEM)and transmission electron micros-copy (TEM).SEM images were acquired with a Hitachi S-800field emission microscope using an acceleration voltage of 20kV.The samples were coated with Au prior to analysis and imaged directly.TEM images were obtained on a JEOL JEM-2000FX Πmicroscope using an electron beam generated by a tungsten filament and an accelerating voltage of 160kV,a beam diameter of approximately 1-2µm,and an objective lens aperture of 20µm.The sample grids were prepared via sonication of powdered sample in ethanol for 10min and evaporating 1drop of the suspension onto a carbon-coated,porous film supported on a 3mm,200-300mesh copper grid.TEM images were recorded at a magnification of 100000-400000×.The magnification was calibrated in pixels per nanometer on the camera.3.Results and Discussion3.1.Effect of Ba/Ti Ratio.BaTiO 3powder,prepared with Ba/Ti ratio in the range of 1.2-2.0,was characterized by XRD,SEM,and TEM techniques to study the cubic -tetragonal phase transformations and surface modifications of BaTiO 3.The ratio of Ba/Ti was chosen to be greater than 1to avoid contamination of BaTiO 3(s)with excess TiO 2(s)under the conditions of hydrothermal synthesis.24Furthermore,Ba/Ti >1increases the pH of the solution,which is an important thermodynamicvariable for the synthesis of perovskite materials,and helps to avoid the addition of an alkaline mineralizer to facilitate the formation of BaTiO 3.According to the thermodynamic calcula-tions of stability diagrams for the hydrothermal Ba -Ti system,high pH and Ba/Ti >1are necessary for the synthesis of high-purity BaTiO 3crystals.28XRD patterns of the as-synthesized BaTiO 3,with Ba/Ti ratios of 1.2,1.4,1.6,1.8,and 2.0,showed the characteristic peaks of both cubic BaTiO 3(JCPDS File No.79-2263)and those of BaCO 3for both TiO 2precursors.Modest BaCO 3contamination was noted in almost all the samples due to the introduction of airborne CO 2,which would dissolve as CO 32-and reacts with Ba 2+to form BaCO 3during the posttreatment.26,36The formation of BaCO 3,observed in this work,is quite common in the hydrothermal processing as BaCO 3can precipitate at lower pH values than those needed to precipitate BaTiO 3.24AccordingtoFigure 1.XRD patterns of BaTiO 3synthesized at various Ba/Ti ratios using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors and washed with formic acid followed by calcination at 900°C (2h).Table 1.Effect of Ba/Ti Ratio and Calcination Temperature on the Crystalline Phase of BaTiO 3calcination temp (°C)Ti precursor Ba/Ti ratio synthesis temp (°C)synthesis time (h)9001150crystalline phase HCl-TiO 21.21606--cubic 1.41606--cubic 1.61606--cubic 1.81606--cubic2.01606--cubic HClO 4-TiO 21.21606--cubic 1.41606--cubic 1.61606--cubic 1.81606--cubic2.01606--cubic HCl-TiO 21.21606yes -cubic 1.41606yes -cubic 1.61606yes -cubic 1.81606yes -cubic2.01606yes -cubic HClO 4-TiO 21.21606yes -cubic 1.41606yes -cubic 1.61606yes -cubic 1.81606yes -cubic2.01606yes -cubic HCl-TiO 21.21606-yes cubic 1.41606-yes cubic 1.61606-yes cubic 1.81606-yes cubic2.01606-yes cubic HClO 4-TiO 21.21606-yes tetragonal 1.41606-yes tetragonal 1.61606-yes tetragonal 1.81606-yes tetragonal2.01606-yestetragonalInd.Eng.Chem.Res.,Vol.47,No.6,20081869the thermodynamic stability diagram of Ba -Ti systems,BaCO 3precipitates at lower pH values than those needed to precipitate BaTiO 3.28Moreover,the formation of BaCO 3is more predomi-nant in BaTiO 3prepared using HClO 4-TiO 2,which indicates its lower pH compared with those prepared using HCl-TiO 2.The relative pH of HClO 4is lower than that of HCl as the p K a values of HClO 4and HCl are -10and -7,respectively.37The XRD results of the as-synthesized BaTiO 3illustrate the absence of apparent peak splitting at 2θ)45°,which corre-sponds to the tetragonal phase of BaTiO 3(JCPDS Card No.5-0626)and hence confirmed the cubic structure with symmetry Pm 3m .In order to remove BaCO 3,the powders were washed with formic acid and calcined at 900°C for 2h.Figure 1shows XRD patterns of BaTiO 3chemically treated with formic acid and calcined at 900°C,which confirms the removal of BaCO 3from BaTiO 3prepared using HCl-TiO 2and HClO 4-TiO 2.Moreover,it indicates that there is no change in the cubic phase of BaTiO 3upon treatment with formic acid.The effect of Ba/Ti ratio and calcination temperature on the crystal structure of BaTiO 3is summarized in Table 1.It can be observed that,even at a Ba/Ti molar ratio of 2without heat treatment,the tetragonal splitting of the diffraction peaks corresponding to the (200)and (002)planes of the perovskite BaTiO 3could not be distinguished,indicating the presence of pure cubic crystalline phase.Shi et al.36observed tetragonal BaTiO 3crystallites when the precursor with high Ba/Ti molar ratio of 3was used,which reduces the probability of forming barium vacancies and stabilized tetragonal phase.The influence of calcination temperature at various Ba/Ti ratios on the cubic -tetragonal phase transition of BaTiO 3can be observed by comparing Figures 1and 2.Figure 2shows the XRD patterns of BaTiO 3prepared using HCl-TiO 2and HClO 4-TiO 2,subjected to calcination at 1150°C.For BaTiO 3samples prepared using HCl-TiO 2,the XRD results show that the crystalline phase is metastable cubic phase for all the samples at 900and 1150°C.The peaks are very sharp,indicating that the crystalline structure is well developed.Generally,the tetragonality of BaTiO 3is deduced from the plane spacing of (002)over that of (200);the corresponding peak appears near 45°in the XRD patterns.Because the peak splitting at 45°is a predominant one to confirm the formation of tetragonal phase,tetragonal splitting of the peaks corresponding to (200)and (002)planes have been chosen to verify the formation of tetragonal phase.Normally,BaTiO 3cubic -tetragonal phase changes begin at 900and 1150°C,but for BaTiO 3prepared using HCl-TiO 2the phase transformation does not proceed to completion even at 1150°C.In the case of BaTiO 3prepared using HClO 4-TiO 2and calcined at 900°C,the XRD patterns are almost identical irrespective of Ba/Ti ratio and cubic phase is observed.However,tetragonal phase was observed at 2θ)45°for the powders synthesized at Ba/Ti ratios of 1.2,1.4,1.6,1.8,and 2.0and calcined at 1150°C for 2h,as shown in Figure 2b.A slight increase in the intensity of tetragonal phase with Ba/Ti ratio may be due to the removal of barium vacancies (charge compensator of OH -defect)by excess barium content,which stabilizes tetragonality.Figures 3and 4show the SEM pictures of BaTiO 3samples prepared using HCl-TiO 2and HClO 4-TiO 2,respectively,at various Ba/Ti ratios of 1.2,1.4,1.6,and 1.8.The particles agglomerated in a spherical shape with ca.0.05-0.15µm (ca.50-150nm)diameters.A possible mechanism for the formation of BaTiO 3by hydrothermal synthesis is the dissolution-Figure 2.XRD patterns of BaTiO 3synthesized at various Ba/Ti ratios using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors and calcined at 1150°C (2h).Figure 3.SEM micrographs of as-synthesized BaTiO 3prepared using HCl-TiO 2at various Ba/Ti ratios:(a)1.2,(b)1.4,(c)1.6,and (d)1.8.1870Ind.Eng.Chem.Res.,Vol.47,No.6,2008precipitation method,38in which there is a chemical equilibrium between TiO 2and [Ti(OH)x ]4-x .[Ti(OH)x ]4-x ,which is a highly active species,can combine with Ba 2+to form a new nucleus,and hence,with an increase in Ba/Ti ratio the chance for the formation of a new nucleus by [Ti(OH)x ]4-x increases and leads to a decrease in the particle size of BaTiO 3.Figure 3shows the decrease in the particle size of BaTiO 3with an increase in Ba/Ti ratio,which is in accord with the dissolution -precipitation mechanism.TEM results show that the primary particles of the sample prepared at Ba/Ti ratios of 1.2and 1.4using HCl-TiO 2as precursor are spherical in shape with 50-60nm diameters,as shown in Figure 5a,b,whereas the particle sizes of BaTiO 3prepared using HClO 4-TiO 2are in the range of 40-50nm diameters (Figure 5c,d).Moreover,it can be ascertained from TEM images that the Ba/Ti ratio increases the cluster size of primary particles.Besides,it should be noted that the stability of cubic and tetragonal phases depends on the critical size of BaTiO 3particles and the critical size was reported to be ∼50nm.39The crystallite size of BaTiO 3is a principal factor controlling tetragonality because the surface defects of nanoc-rystallites are predominant over the bulk ones below a certain critical size of BaTiO 3.The surface defects can prevent the completion of phase transformation,leading to high strains within the crystal.Increase in the cluster size of primary particles reduces the strain within the cubic structure for distortion.It can be concluded that the phase transition of cubic BaTiO 3occurs at 1150°C irrespective of Ba/Ti ratio when HClO 4-TiO 2was used as the TiO 2precursor.Moreover,the primaryparticleFigure 4.SEM micrographs of as-synthesized BaTiO 3prepared using HClO 4-TiO 2at various Ba/Ti ratios:(a)1.2,(b)1.4,(c)1.6,and (d)1.8.Figure 5.TEM micrographs of BaTiO 3prepared using (a)HCl-TiO 2,Ba/Ti )1.2;(b)HCl-TiO 2,Ba/Ti )1.4;(c)HClO 4-TiO 2,Ba/Ti )1.2;and (d)HClO 4-TiO 2,Ba/Ti )1.4.Figure 6.XRD patterns of BaTiO 3synthesized at various temperatures using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors calcined at 900°C (2h).Ind.Eng.Chem.Res.,Vol.47,No.6,20081871size of BaTiO 3prepared using HClO 4-TiO 2is smaller than that prepared using HCl-TiO 2,which can be ascribed to the smaller particle size of TiO 2prepared by HClO 4.34The agglomeration of BaTiO 3nanoparticles at higher calcination temperature promotes the stability of the tetragonal phase.3.2.Effect of Synthesis Temperature.To study the influence of synthesis temperature on the phase of BaTiO 3and particle morphology,BaTiO 3was prepared at 80,120,160,180,and 200°C while keeping the rest of the process parameters as Ba/Ti )1.2and the synthesis time as 6h.The XRD patterns of BaTiO 3obtained at different reaction temperatures and calcined at 900°C are given in Figure 6.The XRD results illustrated well-developed cubic crystalline phase and the intensity of the peaks increased with reaction temperature.There is a possibility of decrease in the unit-cell volume and decrease in density with an increase in the reaction temperature due to the release of lattice hydroxyls.20The influence of calcination temperature withsynthesis temperature is compiled in Table 2.Figure 7depicts the XRD patterns of BaTiO 3calcined at 1150°C.With increased synthesis temperature,the diffraction peaks related to the (200)and (002)planes of the tetragonal BaTiO 3separated and the c /a ratio of the lattice increased,confirming the cubic -tetragonal phase transition with synthesis temperature.The splitting of the (200)reflection is apparent for the samples synthesized at 180and 200°C,suggesting the tetragonal phase.The intensity ratio of 45°peaks significantly increased as the synthesis temperature increased.The presence of shoulders at 80and 120°C represents the formation of partially tetragonal phase in cubic BaTiO 3.The stabilization of tetragonal phase with increase in temperature may be due to the removal of hydroxyl groups in the BaTiO 3lattice.Figure 8depicts the SEM micrographs of BaTiO 3prepared using HCl-TiO 2at 80,120,180,and 200°C for 24h.The particles agglomerated into a spherical shape,and the particle sizes estimated from the SEM micrographs are within 0.05-0.15µm in diameter.When the synthesis temperature increased from 80to 200°C and with reacting for 24h,the particle size of BaTiO 3increased to 0.09-0.15µm.The shape of the particles was observed to be spherical independent of treated tempera-tures.The increase in the synthesis temperature leads to an increase in the particle size,which may explain the stronger agglomeration at higher temperature.However,for BaTiO 3prepared using HClO 4-TiO 2(Figure 9),the secondary particle size increased from 0.05to 0.10µm with an increase in the reaction temperature from 80to 200°C for 24h,confirming that the particle size of BaTiO 3was dependent on synthesis temperature.The overall shape of the agglomerated secondary particle size was estimated to be 0.05-0.10µm in diameter.As shown in Figure 10,the particles consist of near-monodis-perse spherical nanoparticles of BaTiO 3.The agglomeration of primary particles with an increase in the reaction temperature can be identified from TEM images,as shown in Figure 10.The clusters of primary particles observed for HClO 4-TiO 2precursor are more than those of HCl-TiO 2.This result suggested that the crystallite size is one of the vital factors that control tetragonality.At a higher reaction temperature,the phase transition has occurred from cubic to tetragonal.3.3.Effect of Calcination Temperature.The stability of the cubic phase in BaTiO 3prepared by hydrothermal synthesis at room temperature may be accounted for by the presence of weakly bound water molecules absorbed onto the surface of the particles and the more strongly bonded structural water as lattice OH -ions.The content of barium vacancy as well as OH -defects in the cubic crystallites is higher than that inTable 2.Effect of Synthesis Temperature and Calcination Temperature on the Crystalline Phase of BaTiO 3calcination temp (°C)Ti precursor Ba/Ti ratio synthesis temp (°C)synthesis time (h)9001150crystalline phase HCl-TiO 21.2806--cubic 1.21206--cubic 1.21606--cubic 1.21806--cubic 1.22006--cubic HClO 4-TiO 21.2806--cubic 1.21206--cubic 1.21606--cubic 1.21806--cubic 1.22006--cubic HCl-TiO 21.2806yes -cubic 1.21206yes -cubic 1.21606yes -cubic 1.21806yes -cubic 1.22006yes -cubic HClO 4-TiO 21.2806yes -cubic 1.21206yes -cubic 1.21606yes -cubic 1.21806yes -cubic 1.22006yes -cubic HCl-TiO 21.2806-yes cubic 1.21206-yes cubic 1.21606-yes cubic 1.21806-yes tetragonal 1.22006-yes tetragonal HClO 4-TiO 21.2806-yes cubic 1.21206-yes cubic 1.21606-yes tetragonal 1.21806-yes tetragonal 1.22006-yestetragonalFigure 7.XRD patterns of BaTiO 3synthesized (Ba/Ti )1.2)at various temperatures using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors and calcined at 1150°C (2h).1872Ind.Eng.Chem.Res.,Vol.47,No.6,2008tetragonal phase.The cubic -tetragonal phase transformation at higher reaction temperature and calcination temperature is due to the elimination of OH -vacancies from the lattice with heat treatment,which leads to the tetragonal stability.At the Curie point,where BaTiO 3undergoes a phase transition,the relative displacement of cation sublattice to O 2-sublattice causes the phase transition of BaTiO 3from cubic to tetragonal.The oxygen vacancies have significant mobility above 650°C,whereas the cation vacancies acquire measurable mobility only above 1050°C.24Moreover,the decrease in the lattice parameter of the crystallites with temperature led to the conclusion that the removal of OH -defects caused the enlargement of the unit cell and released the lattice strain to form the tetragonal phase.3.4.Effect of Synthesis Time.The effect of synthesis time on the formation of crystalline BaTiO 3was also studied by performing the experiments at different reaction times ranging from 3to 24h at 160°C with Ba/Ti )1.2.The crystalline form at shorter periods of time,viz.,3and 6h,is primarily the metastable cubic form.SEM micrographs indicated no signifi-cant difference in the morphology.The cluster size was larger by extending the processing time,but the particle size has no significant difference.BaTiO 3powders prepared by using HClO 4-TiO 2as the precursor resulted similarly to those prepared by using HCl-TiO 2as the precursor.The XRD patterns as shown in Figure 11confirm the cubic phase of BaTiO 3prepared using HCl-TiO 2and HClO 4-TiO 2calcined at 900°C.Figure 12a shows the typical phase transformation of BaTiO 3prepared using HCl-TiO 2.When BaTiO 3prepared using HCl-TiO 2was treated for 12h,a noticeable peak splitting appeared.With increasing reaction time from 12to 24h,the intensity and sharpness of the tetragonal peak splitting increased,indicating an increase in the crystallinity of the tetragonal phase along with anincreaseFigure 8.SEM micrographs of BaTiO 3synthesized using HCl-TiO 2at various temperatures:(a)80,(b)120,(c)180,and (d)200°C.Figure 9.SEM micrographs of BaTiO 3synthesized using HClO 4-TiO 2at various temperatures:(a)80,(b)120,(c)180,and (d)200°C.Figure 10.TEM micrographs of BaTiO 3prepared using (a)HCl-TiO 2,120°C;(b)HCl-TiO 2,180°C;(c)HClO 4-TiO 2,120°C;and (d)HClO 4-TiO 2,180°C.Ind.Eng.Chem.Res.,Vol.47,No.6,20081873in the particle size of BaTiO 3.The results are summarized in Table 3.The tetragonal BaTiO 3can be synthesized from HCl-TiO 2at reaction times of 12and 24h using Ba/Ti ratio of 1.2,synthesis temperature of 160°C,and calcination temperature at 1150°C for 2h.However,even at 3h reaction time,BaTiO 3prepared using HClO 4-TiO 2achieved the cubic -tetragonal phase transformation (Figure 12b).The reason can be ascribed to the acidic nature of HClO 4,which leads to the formation of BaTiO 3with fewer defects so as to stabilize the tetragonal phase apart from the possible influence of Cl -ions present in the reaction mixture.The presence of chloride ions is speculated to influence the diffusion of Ba 2+ions and retard the crystal growth process,thereby stabilizing the tetragonal phase by forming larger crystals.40In the early stage of reaction,chloride ions produce more nuclei and form smaller particles,which grow larger at prolonged time.Sun and Li 41reported that BaTiO 3particles synthesized in the presence of chloride ions are slightly larger than the particles synthesized in the absence of chloride ions,however,with an enhanced tetragonality compared to the latter.The physicochemical properties of TiO 2prepared from HCl and HClO 4make the difference in the properties of BaTiO 3.34Therefore,it is concluded that the BaTiO 3tetragonal phase can be successfully synthesized using HClO 4-TiO 2as the precursor at a [H +]/[Ti 4+]ratio of 1.2,synthesis temperature of 160°C,and calcination temperature of 1150°C (2h).344.ConclusionIn the present study,the morphology and phase transformation of BaTiO 3prepared using HCl-TiO 2and HClO 4-TiO 2with respect to reaction temperature,reaction time,Ba/Ti ratio,and calcination time were investigated.Increase in Ba/Ti ratio,temperature,and reaction time increases the possibility of cubic phase transformations.Well-crystallized tetragonal BaTiO 3powders of high purity were obtained using HCl-TiO 2as the precursor at optimum conditions of Ba/Ti ratio )1.2,temper-Figure 11.XRD patterns of BaTiO 3synthesized at various reaction times using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors calcined at 900°C (2h).Figure 12.XRD patterns of BaTiO 3synthesized at various reaction times using (a)HCl-TiO 2and (b)HClO 4-TiO 2precursors.Conditions:reaction temperature )160°C;Ba/Ti )1.2;calcination temperature )1150°C (2h).Table 3.Effect of Synthesis Time and Calcination Temperature on the Crystalline Phase of BaTiO 3calcination temp (°C)Ti precursor Ba/Ti ratio synthesis temp (°C)synthesis time (h)9001150crystalline phase HCl-TiO 21.21603--cubic 1.21606--cubic 1.216012--cubic 1.216024--cubic HClO 4-TiO 21.21603--cubic 1.21606--cubic 1.216012--cubic 1.216024--cubic HCl-TiO 21.21603yes -cubic 1.21606yes -cubic 1.216012yes -cubic 1.216024yes -cubic HClO 4-TiO 21.21603yes -cubic 1.21606yes -cubic 1.216012yes -cubic 1.216024yes -cubic HCl-TiO 21.21603-yes cubic 1.21606-yes cubic 1.216012-yes tetragonal 1.216024-yes tetragonal HClO 4-TiO 21.21603-yes tetragonal 1.21606-yes tetragonal 1.216012-yes tetragonal 1.216024-yestetragonal1874Ind.Eng.Chem.Res.,Vol.47,No.6,2008ature)180°C,synthesis time)6h,and calcination at 1150°C for2h.However,the phase transformation of BaTiO3 prepared using HClO4-TiO2occurred at lower reaction temper-ature(160°C)and synthesis time(3h)than BaTiO3particles prepared using HCl-TiO2.BaTiO3particles are agglomerated to a spherical shape with ca.80-90nm and BaTiO3particles synthesized with HClO4-TiO2were smaller than those prepared by HCl-TiO2.The stabilization of cubic BaTiO3is caused by defects including OH-defects and barium vacancies.The formation of tetragonal BaTiO3is promoted by the use of high reaction temperature,calcination temperature,and reaction time, which reduces the probability of forming OH-vacancies.In summary,the precursor has a strong influence on the size and morphology of BaTiO3.BaTiO3prepared from HClO4-TiO2 indeed increases the transformation of cubic-to-tetragonal phase at lower reaction conditions without significant particle growth. 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影响晶型转变的因素众所周知,结构决定性质,而对于晶体来说,当外界条件变化时,晶体结构形式发生改变,碳、硅、金属的单质、硫化锌、氧化铁、二氧化硅以及其他很多物质都具有这一现象,所以本文通过查阅文献举例说明影响晶型的一些因素,主要有温度、压力、粒度和组成。
一、温度温度对晶型影响比较复杂,当温度升高时,晶体中的分子或某些离子团自由旋转,取得较高的对称性,而改变晶体的结构。
下面举例说明:(1) BaO·Al2O3·SiO2(BAS)系微晶玻璃的主晶相为钡长石。
钡长石主要的晶型有单斜钡长石(monoclinic celsian)、六方钡长石( hexa celsian)和正交钡长石(orthorhombic celsian),三者的关系如图1所示:Fig. 1 The phase transformation of celsian由图中我们可以看到:六方钡长石膨胀系数高,为8. 0×10-6/℃,而且在300℃左右会发生其向正交钡长石的可逆转变,转变过程中伴随着3-4%的体积变化。
(2)当预热温度小于400℃时,反应所得到的产物氧化铝为非晶态的A12O3。
非晶A12O3。
在热力学上是一种亚稳状态,所以它有向晶态转化的趋势。
当温度不够高时,非晶A12O3中的原子的运动幅度较小,同时晶化所必不可少的晶核的形成和生长都比较困难,因此非晶态向晶态的转化就不易。
为研究所制备的非晶A12O3。
向晶态Al2O3转变的规律,我们把在300℃时点火得到的非晶A12O3 进行了锻烧处理,结果见表2:Fig.1 XRD Patterns of Produets kept for 1.5h at 700一900℃Fig.2 XRD Pattems of produets kept for o.5h at l000一l200℃Fig.3 XRD Pattems of produets kept for o.5h at l000℃ and l200℃Fig.4 XRD Pattems of produets kept for different time at l000℃Fig.5 XRD Pattems of produets kept for different time at 1100℃从图1中可以看到,非晶态的氧化铝经700、800、900℃锻烧1.5h后,氧化铝从非晶态转变为r-A12O3,并且随着温度的升高r- A12O3。
材料科学基础常用英语词汇 (下文是金属材料词汇)材料的类型Types of materials, metals, ceramics, polymers, composites, elastomer部分材料性质复习Review of selected properties of materials,电导率和电阻率conductivity and resistivity,热导率thermal conductivity,应力和应变stress and strain,弹性应变elastic strain,塑性应变plastic strain,屈服强度yield strength,最大抗拉强度ultimate tensile strength,最大强度ultimate strength,延展性ductility,伸长率elongation,断面收缩率reduction of area,颈缩necking,断裂强度breaking strength,韧性toughness,硬度hardness,疲劳强度fatigue strength,蜂窝honeycomb,热脆性heat shortness,晶胞中的原子数atoms per cell,点阵lattice, 阵点lattice point,点阵参数lattice parameter,密排六方hexagonal close-packed,六方晶胞hexagonal unit cell,体心立方body-centered cubic,面心立方face-centered cubic,弥勒指数Miller indices,晶面crystal plane,晶系crystal system,晶向crystal direction,相变机理Phase transformation mechanism:成核生长相变nucleation–growth transition, 斯宾那多分解spinodal decomposition,有序无序转变disordered-order transition, 马氏体相变martensite phase transformation,成核nucleation,成核机理nucleation mechanism,成核势垒nucleation barrier,晶核,结晶中心nucleus of crystal,(金属组织的)基体quay,基体,基块,基质,结合剂matrix,子晶,雏晶matted crystal,耔晶,晶种seed crystal,耔晶取向seed orientation,籽晶生长seeded growth,均质核化homogeneous nucleation,异质核化heterogeneous nucleation,均匀化热处理homogenization heat treatment, 熟料grog,自恰场self-consistent field固溶体Solid solution:有序固溶体ordered solid solution,无序固溶体disordered solid solution,有序合金ordered alloy,无序合金disordered alloy.无序点阵disordered lattice,分散,扩散,弥散dispersal,分散剂dispersant,分散剂,添加剂dispersant additive,分散剂,弥散剂dispersant agent缺陷defect, imperfection,点缺陷point defect,线缺陷 line defect, dislocation,面缺陷interface defect, surface defect,体缺陷volume defect,位错排列dislocation arrangement,位错阵列dislocation array,位错气团dislocation atmosphere,位错轴dislocation axis,位错胞dislocation cell,位错爬移dislocation climb,位错滑移dislocation slip, dislocation movement by slip, 位错聚结dislocation coalescence,位错核心能量dislocation core energy,位错裂纹dislocation crack,位错阻尼dislocation damping,位错密度dislocation density,体积膨胀volume dilation,体积收缩volume shrinkage,回火tempering,退火annealing,退火的,软化的softened,软化退火,软化(处理)softening,淬火quenching,淬火硬化quenching hardening,正火normalizing, normalization,退火织构annealing texture,人工时效artificial aging,细长比aspect ratio,形变热处理ausforming,等温退火austempering,奥氏体austenite,奥氏体化austenitizing,贝氏体bainite,马氏体martensite,马氏体淬火marquench,马氏体退火martemper,马氏体时效钢maraging steel,渗碳体cementite,固溶强化solid solution strengthening,钢屑混凝土steel chips concrete,水玻璃,硅酸钠sodium silicate,水玻璃粘结剂sodium silicate binder,硅酸钠类防水剂sodium silicate waterproofing agent, 扩散diffusion,扩散系数diffusivity,相变phase transition,烧结sintering,固相反应solid-phase reaction,相图与相结构phase diagrams and phase structures , 相phase,组分component,自由度freedom,相平衡phase equilibrium,吉布斯相律Gibbs phase rule,吉布斯自由能Gibbs free energy,吉布斯混合能Gibbs energy of mixing,吉布斯熵Gibbs entropy,吉布斯函数Gibbs function,相平衡phase balance,相界phase boundary,相界线 phase boundary line,相界交联 phase boundary crosslinking,相界有限交联phase boundary crosslinking,相界反应phase boundary reaction,相变phase change,相组成phase composition,共格相 phase-coherent,金相相组织 phase constentuent,相衬phase contrast,相衬显微镜phase contrast microscope,相衬显微术phase contrast microscopy,相分布phase distribution,相平衡常数phase equilibrium constant,相平衡图phase equilibrium diagram,相变滞后phase transition lag, Al-Si-O-N系统相关系phase relationships in the Al-Si-O-N system, 相分离phase segregation, phase separation,玻璃分相phase separation in glasses,相序phase order, phase sequence,相稳定性phase stability,相态phase state,相稳定区phase stabile range,相变温度phase transition temperature,相变压力phase transition pressure,同质多晶转变polymorphic transformation,相平衡条件phase equilibrium conditions,显微结构microstructures,不混溶固溶体immiscible solid solution,转熔型固溶体peritectic solid solution,低共熔体eutectoid,crystallization,不混溶性immiscibility,固态反应solid state reaction,烧结sintering,相变机理Phase transformation mechanism:成核生长相变nucleation–growth transition, 斯宾那多分解spinodal decomposition,有序无序转变disordered-order transition, 马氏体相变martensite phase transformation,成核nucleation,成核机理nucleation mechanism,成核势垒nucleation barrier,晶核,结晶中心nucleus of crystal,(金属组织的)基体quay,基体,基块,基质,结合剂matrix,子晶,雏晶matted crystal,耔晶,晶种seed crystal,耔晶取向seed orientation,籽晶生长seeded growth,均质核化homogeneous nucleation,异质核化heterogeneous nucleation,均匀化热处理homogenization heat treatment, 熟料grog,金属材料词汇物料科学Material Science物料科学定义Material Science Definition加工性能Machinability强度Strength抗腐蚀及耐用Corrosion & resistance durability金属特性Special metallic features抗敏感及环境保护Allergic, re-cycling & environmental protection化学元素Chemical element元素的原子序数Atom of Elements原子及固体物质Atom and solid material原子的组成、大小、体积和单位图表The size, mass, charge of an atom, and is particles (Pronton,Nentron and Electron) 原子的组织图Atom Constitutes周期表Periodic Table原子键结Atom Bonding金属与合金Metal and Alloy铁及非铁金属Ferrous & Non Ferrous Metal金属的特性Features of Metal晶体结构Crystal Pattern晶体结构,定向格子及单位晶格Crystal structure, Space lattice & Unit cellX线结晶分析法X – ray crystal analyics method金属结晶格子Metal space lattice格子常数Lattice constant米勒指数Mill's Index金相及相律Metal Phase and Phase Rule固熔体Solid solution置换型固熔体Substitutional type solid solution插入型固熔体Interstital solid solution金属间化物Intermetallic compound金属变态Transformation变态点Transformation Point磁性变态Magnetic Transformation同素变态Allotropic Transformation合金平衡状态Thermal Equilibrium相律Phase Rule自由度Degree of freedom临界温度Critical temperture共晶Eutectic包晶温度Peritectic Temperature包晶反应Peritectic Reaction包晶合金Peritectic Alloy亚共晶体Hypoeutetic Alloy过共晶体Hyper-ectectic Alloy金属的相融、相融温度、晶体反应及合金在共晶合金、固熔孻共晶合金及偏晶反应的比较Equilibrium Comparision金属塑性Plastic Deformation滑动面Slip Plan畸变Distortion硬化Work Hardening退火Annealing回复柔软Crystal Recovery再结晶Recrystallization金属材料的性能及试验Properties & testing of metal化学性能Chemical Properties物理性能Physical Properties颜色Colour磁性Magnetisum比电阻Specific resistivity & specific resistance比重Specific gravity & specific density比热Specific Heat热膨胀系数Coefficient of thermal expansion导热度Heat conductivity机械性能Mechanical properties屈服强度(降伏强度) (Yield strangth)弹性限度、阳氏弹性系数及屈服点elastic limit, Yeung's module of elasticity to yield point伸长度Elongation断面缩率Reduction of area金属材料的试验方法The Method of Metal inspection不破坏检验Non – destructive inspections渗透探伤法Penetrate inspection磁粉探伤法Magnetic particle inspection放射线探伤法Radiographic inspection超声波探伤法Ultrasonic inspection显微观察法Microscopic inspection破坏的检验Destructive Inspection冲击测试Impact Test疲劳测试Fatigue Test潜变测试Creep Test潜变强度Creeps Strength第壹潜变期Primary Creep第二潜变期Secondary Creep第三潜变期Tertiary Creep主要金属元素之物理性质Physical properties of major Metal Elements工业标准及规格–铁及非铁金属Industrial Standard – Ferrous & Non – ferrous Metal磁力Magnetic简介General软磁Soft Magnetic硬磁Hard Magnetic磁场Magnetic Field磁性感应Magnetic Induction透磁度Magnetic Permeability磁化率Magnetic Susceptibility (Xm)磁力(Magnetic Force)及磁场(Magnetic Field)是因物料里的电子(Electron)活动而产生抗磁体、顺磁体、铁磁体、反铁磁体及亚铁磁体Diamagnetism, Paramagnetic, Ferromagnetism,Antiferromagnetism & Ferrimagnetism 抗磁体Diamagnetism磁偶极子Dipole负磁力效应Negative effect顺磁体Paramagnetic正磁化率Positive magnetic susceptibility铁磁体Ferromagnetism转变元素Transition element交换能量Positive energy exchange外价电子Outer valence electrons化学结合Chemical bond自发上磁Spontaneous magnetization磁畴Magnetic domain相反旋转Opposite span比较抗磁体、顺磁体及铁磁体Comparison of Diamagnetism, Paramagnetic & Ferromagnetism 反铁磁体Antiferromagnetism亚铁磁体Ferrimagnetism磁矩magnetic moment净磁矩Net magnetic moment钢铁的主要成份The major element of steel钢铁用"碳"之含量来分类Classification of Steel according to Carbon contents铁相Steel Phases钢铁的名称Name of steel纯铁体Ferrite渗碳体Cementitle奥氏体Austenite珠光体及共释钢Pearlite &Eutectoid奥氏体碳钢Austenite Carbon Steel单相金属Single Phase Metal共释变态Eutectoid Transformation珠光体Pearlite亚铁释体Hyppo-Eutectoid初释纯铁体Pro-entectoid ferrite过共释钢Hype-eutectoid珠光体Pearlite粗珠光体Coarse pearlite中珠光体Medium pearlite幼珠光体Fine pearlite磁性变态点Magnetic Transformation钢铁的制造Manufacturing of Steel连续铸造法Continuous casting process电炉Electric furnace均热炉Soaking pit全静钢Killed steel半静钢Semi-killed steel沸腾钢(未净钢) Rimmed steel钢铁生产流程Steel Production Flow Chart钢材的熔铸、锻造、挤压及延轧The Casting, Fogging, Extrusion, Rolling & Steel熔铸Casting锻造Fogging挤压Extrusion延轧Rolling冲剪Drawing & stamping特殊钢Special Steel简介General特殊钢以原素分类Classification of Special Steel according to Element 特殊钢以用途来分类Classification of Special Steel according to End Usage 易车(快削)不锈钢Free Cutting Stainless Steel含铅易车钢Leaded Free Cutting Steel含硫易车钢Sulphuric Free Cutting Steel硬化性能Hardenability钢的脆性Brittleness of Steel低温脆性Cold brittleness回火脆性Temper brittleness日工标准下的特殊钢材Specail Steel according to JIS Standard铬钢–日工标准JIS G4104Chrome steel to JIS G4104铬钼钢钢材–日工标准G4105 62Chrome Molybdenum steel to JIS G4105镍铬–日工标准G4102 63Chrome Nickel steel to JIS G4102镍铬钼钢–日工标准G4103 64Nickel, Chrome & Molybdenum Steel to JIS G4103高锰钢铸–日工标准High manganese steel to JIS standard片及板材Chapter Four-Strip, Steel & Plate冷辘低碳钢片(双单光片)(日工标准JIS G3141) 73 - 95Cold Rolled (Low carbon) Steel Strip (to JIS G 3141)简介General美材试标准的冷辘低碳钢片Cold Rolled Steel Strip American Standard – American Society for testing and materials (ASTM) 日工标准JIS G3141冷辘低碳钢片(双单光片)的编号浅释Decoding of cold rolled(Low carbon)steel strip JIS G3141材料的加工性能Drawing abillity硬度Hardness表面处理Surface finish冷辘钢捆片及张片制作流程图表Production flow chart cold rolled steel coil sheet冷辘钢捆片及张片的电镀和印刷方法Cold rolled steel coil & sheet electro-plating & painting method冷辘(低碳)钢片的分类用、途、工业标准、品质、加热状态及硬度表End usages, industrial standard, quality, condition and hardness of cold rolled steel strip硬度及拉力Hardness & Tensile strength test拉伸测试(顺纹测试)Elongation test杯突测试(厚度: 0.4公厘至1.6公厘,准确至0.1公厘3个试片平均数)Erichsen test (Thickness: 0.4mm to 1.6mm, figure round up to 0.1mm)曲面(假曲率)Camber厚度及阔度公差Tolerance on Thickness & Width平坦度(阔度大于500公厘,标准回火)Flatness (width>500mm, temper: standard)弯度Camber冷辘钢片储存与处理提示General advice on handling & storage of cold rolled steel coil & sheet防止生锈Rust Protection生锈速度表Speed of rusting焊接Welding气焊Gas Welding埋弧焊Submerged-arc Welding电阻焊Resistance Welding冷辘钢片(拉力: 30-32公斤/平方米)在没有表面处理状态下的焊接状况Spot welding conditions for bared (free from paint, oxides etc) Cold rolled mild steel sheets(T/S:30-32 Kgf/ μ m2)时间效应(老化)及拉伸应变Aging & Stretcher Strains日工标准(JIS G3141)冷辘钢片化学成份Chemical composition – cold rolled steel sheet to JIS G3141冷辘钢片的"理论重量"计算方程式Cold Rolled Steel Sheet – Theoretical mass日工标准(JIS G3141)冷辘钢片重量列表Mass of Cold-Rolled Steel Sheet to JIS G3141冷辘钢片订货需知Ordering of cold rolled steel strip/sheet其它日工标准冷轧钢片(用途及编号)JIS standard & application of other cold Rolled Special Steel电镀锌钢片或电解钢片Electro-galvanized Steel Sheet/Electrolytic Zinc Coated Steel Sheet简介General电解/电镀锌大大增强钢片的防锈能力Galvanic Action improving Weather & Corrosion Resistance of the Base Steel Sheet上漆能力Paint Adhesion电镀锌钢片的焊接Welding of Electro-galvanized steel sheet点焊Spot welding滚焊Seam welding电镀锌(电解)钢片Electro-galvanized Steel Sheet生产流程Production Flow Chart常用的镀锌钢片(电解片)的基层金属、用途、日工标准、美材标准及一般厚度Base metal, application, JIS & ASTM standard, and Normal thickness of galvanized steel sheet锌镀层质量Zinc Coating Mass表面处理Surface Treatment冷轧钢片Cold-Rolled Steel Sheet/Strip热轧钢片Hot-Rolled Sheet/Strip电解冷轧钢片厚度公差Thickness Tolerance of Electrolytic Cold-rolled sheet热轧钢片厚度公差Thickness Tolerance of Hot-rolled sheet冷轧或热轧钢片阔度公差Width Tolerance of Cold or Hot-rolled sheet长度公差Length Tolerance理论质量Theoretical Mass锌镀层质量(两个相同锌镀层厚度)Mass Calculation of coating (For equal coating)/MM锌镀层质量(两个不同锌镀层厚度)Mass Calculation of coating (For differential coating)/MM镀锡薄铁片(白铁皮/马口铁) (日工标准JIS G3303)简介General镀锡薄铁片的构造Construction of Electrolytic Tinplate镀锡薄钢片(白铁皮/马日铁)制造过程Production Process of Electrolytic Tinplate锡层质量Mass of Tin Coating (JIS G3303-1987)两面均等锡层Both Side Equally Coated Mass两面不均等锡层Both Side Different Thickness Coated Mass级别、电镀方法、镀层质量及常用称号Grade, Plating type, Designation of Coating Mass & Common Coating Mass 镀层质量标记Markings & Designations of Differential Coatings硬度Hardness单相轧压镀锡薄铁片(白铁皮/马口铁)Single-Reduced Tinplate双相辗压镀锡薄钢片(马口铁/白铁皮)Dual-Reduction Tinplate钢的种类Type of Steel表面处理Surface Finish常用尺寸Commonly Used Size电器用硅[硅] 钢片Electrical Steel Sheet简介General软磁材料Soft Magnetic Material滞后回线Narrow Hystersis矫顽磁力Coercive Force硬磁材料Hard Magnetic Material最大能量积Maximum Energy Product硅含量对电器用的低碳钢片的最大好处The Advantage of Using Silicon low Carbon Steel晶粒取向(Grain-Oriented)及非晶粒取向(Non-Oriented)Grain Oriented & Non-Oriented电器用硅[硅] 钢片的最终用途及规格End Usage and Designations of Electrical Steel Strip电器用的硅[硅] 钢片之分类Classification of Silicon Steel Sheet for Electrical Use电器用钢片的绝缘涂层Performance of Surface Insulation of Electrical Steel Sheets晶粒取向电器用硅钢片主要工业标准International Standard – Grain-Oriented Electrical Steel Silicon Steel Sheet for Electrical Use晶粒取向电器用硅钢片Grain-Oriented Electrical Steel晶粒取向,定取向芯钢片及高硼定取向芯钢片之磁力性能及夹层系数(日工标准及美材标准)Magnetic Properties and Lamination Factor of SI-ORIENT-CORE& SI-ORIENT-CORE-HI B Electrical Steel Strip (JIS and AISI Standard)退火Annealing电器用钢片用家需自行应力退火原因Annealing of the Electrical Steel Sheet退火时注意事项Annealing Precautionary碳污染Prevent Carbon Contamination热力应先从工件边缘透入Heat from the Laminated Stacks Edges提防过份氧化No Excessive Oxidation应力退火温度Stress –relieving Annealing Temperature晶粒取向电器用硅[硅] 钢片–高硼(HI-B)定取向芯钢片及定取向芯钢片之机械性能及夹层系数Mechanical Properties and Lamination Factors of SI-ORIENT-CORE-HI-B and SI-ORIENT-CORE Grain Orient Electrical Steel Sheets晶粒取向电器用硅[硅] 钢;片–高硼低硫(LS)定取向钢片之磁力及电力性能Magnetic and Electrical Properties of SI-ORIENT-CORE-HI-B-LS晶粒取向电器用硅[硅] 钢片–高硼低硫(LS) 定取向钢片之机械性能及夹层系数Mechanical Properties and Lamination Factors of SI-ORIENT-CORE-HI-B-LS晶粒取向电器用硅(硅)钢片-高硼(HI-B)定取向芯钢片,定取向芯钢片及高硼低硫(LS)定取向芯钢片之厚度及阔度公差Physical Tolerance of SI-ORIENT-CORE-HI-B, SI-ORIENT-CORE, & SI-CORE-HI-B-LS Grain Oriented Electrical Steel Sheets晶粒取向电器用硅(硅)钢片–高硼(HI-B)定取向芯钢片,定取向芯钢片及高硼低硫(LS)定取向芯钢片之标准尺寸及包装Standard Forms and Size of SI-ORIENT-CORE-HI-B,SI-CORE, & SI-ORIENT-CORE-HI-B-LS Grain-Oriented Electrical Steel Sheets绝缘表面Surface Insulation非晶粒取向电力用钢片的电力、磁力、机械性能及夹层系数Lamination Factors of Electrical, Magnetic & Mechanical Non-Grain Oriented Electrical电器及家电外壳用镀层冷辘[低碳] 钢片Coated (Low Carbon) Steel Sheets for Casing,Electricals & Home Appliances镀铝硅钢片Aluminized Silicon Alloy Steel Sheet简介General镀铝硅合金钢片的特色Feature of Aluminized Silicon Alloy Steel Sheet用途End Usages抗化学品能力Chemical Resistance镀铝(硅)钢片–日工标准(JIS G3314)Hot-aluminum-coated sheets and coils to JIS G 3314镀铝(硅)钢片–美材试标准(ASTM A-463-77)35.7 JIS G3314镀热浸铝片的机械性能Mechanical Properties of JIS G 3314 Hot-Dip Aluminum-coated Sheets and Coils公差Size Tolerance镀铝(硅)钢片及其它种类钢片的抗腐蚀性能比较Comparsion of various resistance of aluminized steel & other kinds of steel镀铝(硅)钢片生产流程Aluminum Steel Sheet, Production Flow Chart焊接能力Weldability镀铝钢片的焊接状态(比较冷辘钢片)Tips on welding of Aluminized sheet in comparasion with cold rolled steel strip钢板Steel Plate钢板用途分类及各国钢板的工业标准包括日工标准及美材试标准Type of steel Plate & Related JIS, ASTM and Other Major Industrial Standards钢板生产流程Production Flow Chart钢板订货需知Ordering of Steel Plate不锈钢Stainless Steel不锈钢的定义Definition of Stainless Steel不锈钢之分类,耐腐蚀性及耐热性Classification, Corrosion Resistant & Heat Resistance of Stainless Steel铁铬系不锈钢片Chrome Stainless Steel马氏体不锈钢Martensite Stainless Steel低碳马氏体不锈钢Low Carbon Martensite Stainless Steel含铁体不锈钢Ferrite Stainless Steel镍铬系不锈钢Nickel Chrome Stainless Steel释出硬化不锈钢Precipitation Hardening Stainless Steel铁锰铝不锈钢Fe / Mn / Al / Stainless Steel不锈钢的磁性Magnetic Property & Stainless Steel不锈钢箔、卷片、片及板之厚度分类Classification of Foil, Strip, Sheet & Plate by Thickness表面保护胶纸Surface protection film不锈钢片材常用代号Designation of SUS Steel Special Use Stainless表面处理Surface finish薄卷片及薄片(0.3至2.9mm厚之片)机械性能Mechanical Properties of Thin Stainless Steel(Thickness from 0.3mm to 2.9mm) – strip/sheet不锈钢片机械性能(301, 304, 631, CSP)Mechanical Properties of Spring use Stainless Steel不锈钢–种类,工业标准,化学成份,特点及主要用途Stainless Steel – Type, Industrial Standard, Chemical Composition, Characteristic & end usage of the most commonly used Stainless Steel不锈钢薄片用途例End Usage of Thinner Gauge不锈钢片、板用途例Examples of End Usages of Strip, Sheet & Plate不锈钢应力退火卷片常用规格名词图解General Specification of Tension Annealed Stainless Steel Strips耐热不锈钢Heat-Resistance Stainless Steel镍铬系耐热不锈钢特性、化学成份、及操作温度Heat-Resistance Stainless Steel铬系耐热钢Chrome Heat Resistance Steel镍铬耐热钢Ni - Cr Heat Resistance Steel超耐热钢Special Heat Resistance Steel抗热超级合金Heat Resistance Super Alloy耐热不锈钢比重表Specific Gravity of Heat – resistance steel plates and sheets stainless steel不锈钢材及耐热钢材标准对照表Stainless and Heat-Resisting Steels发条片Power Spring Strip发条的分类及材料Power Spring Strip Classification and Materials上链发条Wind-up Spring倒后擦发条Pull Back Power Spring圆面("卜竹")发条Convex Spring Strip拉尺发条Measure Tape魔术手环Magic Tape魔术手环尺寸图Drawing of Magic Tap定型发条Constant Torque Spring定型发条及上炼发条的驱动力Spring Force of Constant Torque Spring and Wing-up Spring定型发条的形状及翻动过程Shape and Spring Back of Constant Torque Spring定型发条驱动力公式及代号The Formula and Symbol of Constant Torque Spring边缘处理Edge Finish硬度Hardness高碳钢化学成份及用途High Carbon Tool Steel, Chemical Composition and Usage每公斤发条的长度简易公式The Length of 1 Kg of Spring Steel StripSK-5 & AISI-301 每公斤长的重量/公斤(阔100-200公厘) Weight per one meter long (kg) (Width 100-200mm)SK-5 & AISI-301 每公斤之长度(阔100-200公厘) Length per one kg (Width 100-200mm)SK-5 & AISI-301 每公尺长的重量/公斤(阔2.0-10公厘)Weight per one meter long (kg) (Width 2.0-10mm)SK-5 & AISI-301 每公斤之长度(阔2.0-10公厘)Length per one kg (Width 2.0-10mm)高碳钢片High Carbon Steel Strip分类Classification用组织结构分类Classification According to Grain Structure用含碳量分类–即低碳钢、中碳钢及高碳钢Classification According to Carbon Contains弹簧用碳钢片CarbonSteel Strip For Spring Use冷轧状态Cold Rolled Strip回火状态Annealed Strip淬火及回火状态Hardened & Tempered Strip/ Precision – Quenched Steel Strip 贝氏体钢片Bainite Steel Strip弹簧用碳钢片材之边缘处理Edge Finished淬火剂Quenching Media碳钢回火Tempering回火有低温回火及高温回火Low & High Temperature Tempering高温回火High Temperature Tempering退火Annealing完全退火Full Annealing扩散退火Diffusion Annealing低温退火Low Temperature Annealing中途退火Process Annealing球化退火Spheroidizing Annealing光辉退火Bright Annealing淬火Quenching时间淬火Time Quenching奥氏铁孻回火Austempering马氏铁体淬火Marquenching高碳钢片用途End Usage of High Carbon Steel Strip冷轧高碳钢–日本工业标准Cold-Rolled (Special Steel) Carbon Steel Strip to JIS G3311 电镀金属钢片Plate Metal Strip简介General电镀金属捆片的优点Advantage of Using Plate Metal Strip金属捆片电镀层Plated Layer of Plated Metal Strip镀镍Nickel Plated镀铬Chrome Plated镀黄铜Brass Plated基层金属Base Metal of Plated Metal Strip低碳钢或铁基层金属Iron & Low Carbon as Base Metal不锈钢基层金属Stainless Steel as Base Metal铜基层金属Copper as Base Metal黄铜基层金属Brass as Base Metal轴承合金Bearing Alloy简介General轴承合金–日工标准JIS H 5401Bearing Alloy to JIS H 5401锡基、铅基及锌基轴承合金比较表Comparison of Tin base, Lead base and Zinc base alloy for Bearing purpose易溶合金Fusible Alloy焊接合金Soldering and Brazing Alloy软焊Soldering Alloy软焊合金–日本标准JIS H 4341Soldering Alloy to JIS H 4341硬焊Brazing Alloy其它焊接材料请参阅日工标准目录Other Soldering Material细线材、枝材、棒材Chapter Five Wire, Rod & Bar线材/枝材材质分类及制成品Classification and End Products of Wire/Rod铁线(低碳钢线)日工标准JIS G 3532Low Carbon Steel Wires ( Iron Wire ) to JIS G 3532光线(低碳钢线),火线(退火低碳钢线),铅水线(镀锌低碳钢线)及制造钉用低碳钢线之代号、公差及备注Ordinary Low Carbon Steel Wire, Annealed Low Carbon Steel Wire, Galvanized low Carbon Steel Wire & Low Carbon Steel Wire for nail manufacturing - classification, Symbol of Grade, Tolerance and Remarks.机械性能Mechanical Properites锌包层之重量,铜硫酸盐试验之酸洗次数及测试用卷筒直径Weight of Zinc-Coating, Number of Dippings in Cupric Sulphate Test and Diameters of Mandrel Used for Coiling Test冷冲及冷锻用碳钢线枝Carbon Steel Wire Rods for Cold Heading & Cold Forging (to JIS G3507)级别,代号及化学成份Classification, Symbol of Grade and Chemical Composition直径公差,偏圆度及脱碳层的平均深度Diameter Tolerance, Ovality and Average Decarburized Layer Depth冷拉钢枝材Cold Drawn Carbon Steel Shafting Bar枝材之美工标准,日工标准,用途及化学成份AISI, JIS End Usage and Chemical Composition of Cold Drawn Carbon Steel Shafting Bar冷拉钢板重量表Cold Drawn Steel Bar Weight Table高碳钢线枝High Carbon Steel Wire Rod (to JIS G3506)冷拉高碳钢线Hard Drawn High Carbon Steel Wire(to JIS G3521, ISO-84580-1&2)化学成份分析表Chemical Analysis of Wire Rod线径、公差及机械性能(日本工业标准G 3521)Mechanical Properties (JIS G 3521)琴线(日本标准G3522)Piano Wires ( to G3522)级别,代号,扭曲特性及可用之线材直径Classes, symbols, twisting characteristic and applied Wire Diameters直径,公差及拉力强度Diameter, Tolerance and Tensile Strength裂纹之容许深度及脱碳层Permissible depth of flaw and decarburized layer常用的弹簧不锈钢线-编号,特性,表面处理及化学成份StainlessSpring Wire –National Standard number, Charateristic, Surface finish & Chemical composition弹簧不锈钢线,线径及拉力列表Stainless Spring Steel, Wire diameter and Tensile strength of Spring Wire处理及表面状况Finish & Surface各种不锈钢线在不同处理拉力比较表Tensile Strength of various kinds of Stainless Steel Wire under Different Finish圆径及偏圆度之公差Tolerance of Wire Diameters & Ovality铬镍不锈钢及抗热钢弹簧线材–美国材验学会ASTM A313 –1987Chromium – Nickel Stainless and Heat-resisting Steel Spring Wire – ASTM A313 – 1987化学成份Chemical Composition机械性能Mechanical Properties305, 316, 321及347之拉力表Tensile Strength Requirements for Types 305, 316, 321 and 347A1S1-302 贰级线材之拉力表Tensile Strength of A1S1-302 Wire日本工业标准–不锈钢的化学成份(先数字后字母排列)JIS – Chemical Composition of Stainless Steel (in order of number & alphabet)美国工业标准–不锈钢及防热钢材的化学成份(先数字后字母排列)AISI –Chemical Composition of Stainless Steel & Heat-Resistant Steel(in order of number & alphabet)易车碳钢Free Cutting Carbon Steels (to JIS G4804 )化学成份Chemical composition圆钢枝,方钢枝及六角钢枝之形状及尺寸之公差Tolerance on Shape and Dimensions for Round Steel Bar, Square Steel Bar, Hexagonal Steel Bar 易车(快削)不锈钢Free Cutting Stainless Steel易车(快削)不锈钢种类Type of steel易车(快削)不锈钢拉力表Tensile Strength of Free Cutting Wires枝/棒无芯磨公差表(μ) (μ= 1/100 mm)Rod/Bar Centreless Grind Tolerance易车不锈钢及易车钢之不同尺寸及硬度比较Hardness of Different Types & Size of Free Cutting Steel扁线、半圆线及异形线Flat Wire, Half Round Wire, Shaped Wire and Precision Shaped Fine Wire加工方法Manufacturing Method应用材料Material Used特点Characteristic用途End Usages不锈钢扁线及半圆线常用材料Commonly used materials for Stainless Flat Wire & Half Round Wire扁线公差Flat Wire Tolerance方线公差Square Wire Tolerance。
Crystal structure and phase transitions across the metal-superconductor boundary in the SmFeAsO1-x F x (0 ≤x≤ 0.20) familySerena Margadonna1*, Yasuhiro Takabayashi2, Martin T. McDonald2, MichelaBrunelli3, G. Wu4, R. H. Liu4, X. H. Chen4 & Kosmas Prassides2*1 School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, UK2 Department of Chemistry, University of Durham, Durham DH1 3LE, UK3 European Synchrotron Radiation Facility, 38042 Grenoble, France4 Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China*e-mail: serena.margadonna@, K.Prassides@The fluorine-doped rare-earth iron oxyarsenides, REFeAsO1-x F x (RE =rare earth) have recently emerged as a new family of high-temperature superconductors with transition temperatures (T c) as high as 55 K (refs 1-4). Early work has provided compelling evidence that the undoped parent materials exhibit spin-density-wave (SDW) antiferromagnetic order and undergo a structural phase transition from tetragonal to orthorhombic crystal symmetry upon cooling.5 Both the magnetic and structural instabilities are suppressed upon doping with fluoride ions before the appearance of superconductivity.6,7 Here we use high-resolution synchrotron X-ray diffraction to study the structural properties of SmFeAsO1-x F x (0 ≤x≤ 0.20) in which superconductivity emerges near x ~ 0.07 and T c increases monotonically with doping up to x ~ 0.20.8 We find that orthorhombic symmetry survives through the metal-superconductor boundary well into the superconducting regimeand the structural distortion is only suppressed at doping levels, x≥ 0.15 when the superconducting phase becomes metrically tetragonal. Remarkably this crystal symmetry crossover coincides with reported drastic anomalies in the resistivity and the Hall coefficient8 and a switch of the pressure coefficient of T c from positive to negative,9 thereby implying that the low-temperature structure plays a key role in defining the electronic properties of these superconductors.The possible mechanism of superconductivity in the REFeAsO1-x F x and related REFeAsO1-δ materials is currently unknown. The rapidly developing structural and electronic phenomenology points to considerable similarities with the well-established behaviour of high-T c cuprate superconductors and early theoretical work has suggested that conventional electron-phonon coupling mechanisms are not able to account for the high T c, implying non-BCS origin of the pairing interactions.10-13 The parent REFeAsO phases exhibit both a structural and a magnetic phase transition on cooling in a similar fashion to the parent cuprate phase, La2CuO4.5,14 Upon doping with fluoride ions, again much like La2-x Sr x CuO4, both the crystallographic and magnetic transitions are suppressed in the superconducting compositions,6,7 while T c first increases smoothly before passing over a maximum value at an optimal level of doping. Detailed experimental mapping of the structural and electronic phase diagrams as the doping level varies is necessary before we achieve a fundamental understanding of the superconductivity mechanism.Here we probed the temperature evolution of the structural properties of the SmFeAsO1-x F x(x = 0, 0.05, 0.10, 0.12, 0.15, and 0.20) family by high-resolution synchrotron X-ray powder diffraction and examined the diffraction profiles collected over an angular range of 1° to 40° (d-spacing = 22.85 to 0.59 Å) at various temperaturesbetween 295 and 20 K. Inspection of all diffraction profiles at room temperature readily reveals the tetragonal (T) unit cell (space group P4/nmm) established before for other REFeAsO systems.5,14 Therefore all the SmFeAsO1-x F x compositions studied here are isostructural and adopt the layered ZrCuSiAs-type structure, featuring alternating tetrahedrally coordinated Sm-O/F and Fe-As layers along the crystallographic c axis. Rietveld analysis of the room temperature diffraction profiles proceeded smoothly for all compositions, revealing a monotonic decrease in both lattice constants with increasing doping level, x (SmFeAsO: a T = 3.93880(2) Å, c T = 8.51111(7) Å; SmFeAsO0.80F0.20: a T = 3.93254(4) Å, c T = 8.4842(1) Å). The response of the lattice metrics to F substitution is strongly anisotropic with the interlayer spacing showing a significantly larger contraction than the intralayer dimensions with increasing x (∂ln c T/∂x ~ 1.6×10-2, ∂ln a T/∂x ~ 0.8×10-2).However, the structural behaviour of the SmFeAsO1-x F x compositions is very different on cooling. No reflections violating tetragonal extinction rules are evident for the heavily-doped compositions with x = 0.15 and 0.20 (Fig. 1e and 1f), in which both lattice constants, a and c decrease smoothly with their crystal structure remaining strictly tetragonal down to 20 K (Fig. 2e and 2f). The rate of contraction, dln a/d T and dlnc/d T at ~5 and ~18 ppm K-1 for the a and c lattice constants, respectively is considerably anisotropic and leads to a gradual decrease of the (c/a) ratio with decreasing temperature. This behaviour is in sharp contrast to the observed thermal structural response of the SmFeAsO1-x F x (x = 0, 0.05, 0.10, and 0.12) compositions. In these systems, the tetragonal structure is initially robust upon cooling showing a normal contraction of the lattice parameters and interatomic distances. However, as the samples are cooled further, all hkl (h, k≠ 0) reflections in the diffraction profiles begin first tobroaden before splitting at a characteristic temperature, T s (Fig. 1a-1d) thereby providing the signature of the onset of a structural transformation of the high-temperature tetragonal structure.5,14 Rietveld refinements of the low-temperature diffraction profiles confirm the adoption of the same orthorhombic (O) superstructure of lattice dimensions, b O > a O ~ a T√2 and c O ~ c T (space group Cmma) for all 0 ≤x≤ 0.12 compositions (Fig. 2a-2d). No discontinuity is observed at T s in the thermal response of either the lattice constant, c or the normalised unit cell volume, V. Notably as the doping level, x increases, both the transition temperature, T s (130 K for x = 0 to ~50 K for x =0.10 and 0.12) and the magnitude of the orthorhombic strain coefficient, s =(b O−a O)/(b O+a O) (~2.5×10-3 at 20 K for x = 0 to ~1.1×10-3-1.3×10-3 at 20 K for x = 0.10 and 0.12) decrease smoothly. The results of the final Rietveld refinements at 20 K for the SmFeAsO1-x F x compositions with x = 0, 0.10, and 0.20 are shown in Supplementary Fig. S1a-S1c with the fitted parameters summarised in Supplementary Table S1.The most prominent point arising from the results of the present structural refinements as a function of both temperature and composition is the survival of the orthorhombic crystal symmetry in SmFeAsO1-x F x well beyond the onset of superconductivity. Crossing the metal-to-superconductor boundary at x ~ 0.07 is not accompanied by the complete suppression of the orthorhombic-to-tetragonal structural phase transition and, as for both x = 0.10 and 0.12 compositions studied here T s > T c, both superconducting phases are orthorhombically distorted (Fig. 3). Although with increasing x, T s is shifting continuously to lower temperature values, the tetragonal symmetry in the superconducting state does not appear until well into the T c versus x superconducting dome at x = 0.15.At first sight, given that T c in the SmFeAsO1-x F x family increases smoothlybetween x ~ 0.07 and 0.20, it may appear that the orthorhombic-to-tetragonal crossover is not reflected in the electronic properties despite the clear signature of the structural transformation in the temperature dependence of the resistivity (T s coincides with the temperature at which the first derivative of the temperature-dependent resistivity, dρ/d T shows a maximum, Fig. 3) and in the renormalisation of the bonding interactions within the conducting Fe-As slabs that accompany it (vide infra). However, here we recall two additional significant experimental observations already established for the SmFeAsO1-F x family that point towards the existence of a criticality hidden under the smoothly xshaped superconducting dome at a doping level, x ~ 0.14: (i) the temperature dependence of the resistivity is linear at high temperatures (low temperatures just above T c) for x < 0.14 (x > 0.14); this differing temperature evolution is accompanied by a drop in carrier density as observed by the pronounced rise in the Hall coefficient,8 and (ii) the superconducting response to pressure is drastically different for compositions straddling the x ~ 0.14 doping level (Fig. 3); while for x < 0.14 the pressure coefficient, ∂ln T c/∂P of SmFeAsO1-x F x is strongly positive, it switches sharply to negative at x > 0.14.9 The observation that these pronounced anomalies in the electronic properties coincide exactly with the crossover from orthorhombic (x < 0.14) to tetragonal (x > 0.14) symmetry for the superconducting phase points towards a key role played by the structural order in determining the bonding interactions within the conducting Fe-As slabs and the electronic properties of the SmFeAsO1-x F x superconductors.Fig. 4c shows the doping dependence at 20 K of selected crystallographic bond distances and angles. Gradual substitution of oxide by fluoride ions in the charge-reservoir Sm-O slab is accompanied by a gradual increase in the Sm-O/F distances.Focusing on the conducting Fe-As layer, we find that the thickness of the As-Fe-As slab (Fig. 4a) shows a clear discontinuity in the vicinity of the orthorhombic-to-tetragonal structural crossover at x ~ 0.12. This anomalous response is even more clearly evident in the x dependence of the Fe-As-Fe angles (Fig. 4b). These initially show a gradual increase in the orthorhombic phase as the doping level x increases. However, the suppression of the structural transition and the stabilisation of the tetragonal phase at x = 0.15 is accompanied by a well-defined reduction in the magnitude of the Fe-As-Fe angles. As the geometry of the AsFe4 units (Fig. 4b) sensitively controls both the Fe near- and next-near-neighbour exchange interactions15 and the width of the electronic conduction band,7,16 the structural discontinuities near the critical composition, x ~ 0.14 should be related with the observed electronic anomalies well within the superconducting dome.Powder neutron diffraction studies on the CeFeAsO1-x F x family7 have provided evidence that the magnetic SDW long range order in the parent material is rapidly suppressed upon doping and disappears at a doping level, x ~ 0.06 just before superconductivity emerges. Given the criticality in the structural, electronic and conducting properties at x ~ 0.14 revealed for the SmFeAsO1-x F x family here, it will be intriguing to search for effects of magnetic origin and establish the magnetic response of the normal state in the fluorine-doped rare-earth iron oxyarsenide families well beyond the compositional onset for superconductivity.METHODSSample preparationPolycrystalline samples with nominal composition SmFeAsO1-x F x (0 ≤x≤ 0.20) were synthesised by conventional solid state reactions using high-purity SmAs, SmF3, Fe, and Fe2O3, as described elsewhere.8 The samples were characterised by powder X-ray diffraction and temperature-dependent resistivity and dc magnetisation measurements.Synchrotron X-ray diffractionFor the synchrotron X-ray diffraction measurements, the SmFeAsO1-x F x(x = 0, 0.05, 0.10, 0.12, 0.15, and 0.20) samples were sealed in thin-walled glass capillaries 0.5 mm in diameter. With each sample inside a continuous-flow cryostat, high-statistics synchrotron X-ray powder diffraction data (λ = 0.399861 Å, 2θ = 1° to 50°) were collected at 20 and 200 K in continuous scanning mode with the high-resolution multianalyser powder diffractometer on beamline ID31 at the European Synchrotron Radiation Facility (ESRF), Grenoble, France. Lower statistics diffraction profiles were also recorded on cooling at numerous temperatures between 295 and 20 K over a shorter angular range (2θ = 1° to 40°). Data analysis was performed with the GSAS suite of Rietveld analysis programmes.Y.et al. Iron-based layered superconductor LaO1-x F x FeAs (x = 0.05 -1. Kamihara,0.12) with T c = 26 K. J. Am. Chem. Soc. 130, 3296-3297 (2008).2. Chen, X. H. et al. Superconductivity at 43 K in samarium-arsenide oxidesSmO1-x F x FeAs. Nature453, 761-762 (2008).3. Chen, G. F. et al. Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO1-x F x FeAs. arXiv:0803.3790v3 (2008).4. Ren, Z. A. et al. Superconductivity at 52 K in iron-based F-doped layered quanternary compound PrO1-x F x FeAs. arXiv:0803.4283 (2008).5. de la Cruz, C. et al. Magnetic order close to superconductivity in the iron-based layered LaO1-x F x FeAs systems. Nature453, 899-902 (2008).et al. Competing orders and spin-density-wave instability in LaO1-6. Dong,J.F x FeAs. arXiv:0803.3426 (2008).xet al. Structural and magnetic phase diagram of CeFeAsO1-x F x and its 7. Zhao,J.relationship to high-temperature superconductivity. arXiv:0806.2528 (2008).8. Liu, R. H. et al. Phase diagram and quantum phase transition in newly discovered superconductors: SmO1-x F x FeAs. arXiv:0804.2105v3 (2008).et al. Doping dependence of the pressure response of T c in the 9. Takabayashi,Y.SmO1-x F x FeAs superconductors. J. Am. Chem. Soc. 130, in press (2008).L.et al. Is LaO1−xFxFeAs an electron-phonon superconductor?10. Boeri,arXiv:0803.2703 (2008).C.et al. Coexistence of antiferromagnetism with superconductivity in 11. Cao,LaO1-x F x FeAs. arXiv:0803.3236 (2008).et al. Even parity, orbital singlet and spin triplet pairing for12. Dai,X.superconducting LaO1-x F x FeAs. arXiv:0803.3982 (2008).13. Ma, F. & Lu, Z. Y. Iron-based superconductor LaO1-x F x FeAs superconductor: an antiferromagnetic semimetal. arXiv:0803.3286 (2008).T.et al. Crystallographic phase transition and high-T c14. Nomura,superconductivity in LaOFeAs:F. arXiv:0804.3569 (2008).of the ~150 K anomaly in LaOFeAs; competingOrigin15. Yildirim,T.antiferromagnetic superexchange interactions, frustration, and structural phase transition. arXiv:0804.2252 (2008).16. McQueen, T. A. et al. Intrinsic properties of stoichiometric LaOFeP. arXiv:0805.2149 (2008).Supplementary Information is linked to the online version of the paper at /nature. Acknowledgements We thank the ESRF for access to the synchrotron X-ray facilities. Competing interests statement The authors declare that they have no competing financial interests. Correspondence and requests for materials should be addressed to S.M. or K.P.Figure 1│ Structural characterisation of the SmFeAsO1-x F x family. Selected region of the high-resolution synchrotron X-ray powder diffraction profiles of SmFeAsO1-x F x showing the temperature evolution of the (220)T Bragg reflection (λ = 0.39986 Å). a, x = 0; b, x = 0.05; c, x = 0.10; d, x = 0.12; e, x =0.15; and f, x = 0.20. On cooling, the tetragonal peak splits into a doublet [(040)O, (400)O] for x = 0 – 0.12, while no detectable splitting is found for x = 0.15 and 0.20 even at the ultrahigh resolution of the present data. The width of the (220)T reflection for x = 0, 0.5 begins to increase before the onset of the tetragonal-to-orthorhombic structural transition (at 150 and 130 K, respectively) providing the signature of precursor strain effects associated with the development of local structural inhomogeneities.Figure 2│Temperature evolution of the structural parameters of the SmFeAsO1-x F x family. a, x = 0; b, x = 0.05; c, x = 0.10; d, x = 0.12; e, x =0.15; and f, x = 0.20. The lattice constants are derived from Rietveld refinements of high-resolution synchrotron X-ray powder diffraction data. Green circles label the interlayer c lattice constant (right scale). Red circles label the in-plane a and b lattice constants (left scale). In a-d, the a and b lattice constants are divided by √2 at temperatures below the tetragonal-to-orthorhombic transition.Figure 3│Structural and electronic phase diagram of the SmFeAsO1-x F x family. The red squares mark the superconducting transition temperatures, T c, the green circles the tetragonal-to-orthorhombic structural transition, T s, and the blue triangles the temperature at which the first derivative of the resistivity8 with respect to temperature, dρ/d T displays a maximum, T max,dρ/d T (bottom panel). The top panel shows the doping level dependence of the pressure coefficient of T c, dln T c/d P.9 The shaded bars near x ~ 0.14 mark the boundary for different behaviour of the temperature-dependent resistivity.811Figure 4│Structural parameters of the SmFeAsO1-x F x family as a function of doping. a, Schematic diagram of the crystal structure of SmFeAsO1-x F x. b, Geometry of the AsFe4 units and definition of the three (two) distinct Fe-As-Fe bond angles for the orthorhombic (tetragonal) crystal structure. c, Doping dependence of selected bond distances and angles at 20 K.Figure 1Figure 2Figure 3a bFigure 4。