Phase, crystal struture and sintering behavior of shock-synthesized

Ferroelectric and piezoelectric properties of tungsten substituted SrBi 2Ta 2O 9ferroelectric ceramicsIndrani Coondoo *,S.K.Agarwal a ,A.K.Jha ba Superconductivity and Cryogenics Division,National Physical Laboratory,Dr K.S.Krishnan Road,New Delhi 110012,India bDepartment of Applied Physics,Delhi College of Engineering,Bawana Road,Delhi 110042,India1.IntroductionDefects in crystals significantly influence physical and various other properties of materials [1].For instance,as it is well known,doping by other elements leads to significant changes in the electrical properties of silicon.Historically,‘‘defect engineering’’has been developed in the field of semiconducting materials such as compound semiconductors as well as in diamond,Si and Ge [2–4].Subsequently,the concept of defect engineering has been applied to other functional materials,and the significant improve-ment in material properties have been achieved in high transition-temperature superconductors [5],amorphous SiO 2[6],photonic crystals [7]and also in the field of ferroelectrics,such as BaTiO 3,Pb(Ti,Zr)O 3(PZT),etc.[8,9].Various structural and electrical properties of bismuth layer-structured ferroelectrics (BLSF)are also strongly affected on deviation from stoichiometric composi-tions and defects have been recognized as a crucially important factor [10–13].It has been found that in BLSF small changes in chemical composition result in significantly altered dielectric and ferroelectric properties including dielectric constant and remanent polarization.In SrBi 2Ta 2O 9(SBT)and SrBi 2Nb 2O 9(SBN),orthor-hombic structural distortions with non-centrosymmetric spacegroup A 21am cause spontaneous ferroelectric polarization (P s )along a axis [14,15].SBT,a member of the BLSF family,has occupied an important position among the Pb-free ferroelectric memory materials [16–18].Tungsten (W 6+)has recently been investigated as a dopant for bismuth titanates and lanthanum doped bismuth titanates,in which the remanent polarization was observed to enhance when a small amount of Ti 4+was substituted by W 6+[19,20].With the objective to improve structural,dielectric and ferroelectric proper-ties,the hexavalent tungsten (W 6+)was chosen as a donor cation for partial replacement of the pentavalent tantalum (Ta 5+)SBT.In this report,the effect of tungsten substitution in SBT (SBTW),on the microstructural,ferroelectric and piezoelectric properties is reported.The results including the improvement in polarization properties have been discussed.2.ExperimentalSamples of compositions SrBi 2(W x Ta 1Àx )2O 9(SBWT),with x =0.0,0.025,0.050,0.075,0.10and 0.20were synthesized by solid-state reaction method taking SrCO 3,Bi 2O 3,Ta 2O 5and WO 3(all from Aldrich)in their stoichiometric proportions.The powder mixtures were thoroughly ground and passed through sieve of appropriate size and then calcined at 9008C in air for 2h.The calcined mixtures were ground and admixed with about 1–1.5wt%polyvinyl alcohol (Aldrich)as a binder and then pressed at $300MPa into disk shaped pellets.The pellets were sintered at 12008C for 2h in air.Materials Research Bulletin 44(2009)1288–1292A R T I C L E I N F O Article history:Received 3October 2008Received in revised form 5December 2008Accepted 6January 2009Available online 15January 2009Keywords:A.CeramicsC.X-ray diffractionD.FerroelectricityA B S T R A C TTungsten substituted samples of compositions SrBi 2(W x Ta 1Àx )2O 9(x =0.0,0.025,0.050,0.075,0.10and 0.20)were synthesized by solid-state reaction method and studied for their microstructural,electrical conductivity,ferroelectric and piezoelectric properties.The X-ray diffractograms confirm the formation of single phase layered perovskite structure in the samples with x up to 0.05.The temperaturedependence of dc conductivity vis-a`-vis tungsten content shows a decrease in conductivity,which is attributed to the suppression of oxygen vacancies.The ferroelectric and piezoelectric studies of the W-substituted SBT ceramics show that the remanent polarization and d 33values increases with increasing concentration of tungsten up to x 0.05.Such compositions with low conductivity and high P r values should be excellent materials for highly stable ferroelectric memory devices.ß2009Elsevier Ltd.All rights reserved.*Corresponding author.Present address:Liquid Crystal Group,National Physical Laboratory,Dr K.S.Krishnan Road,New Delhi 110012,India.Tel.:+919810361727;fax:+911125170387.E-mail address:indrani_coondoo@ (I.Coondoo).Contents lists available at ScienceDirectMaterials Research Bulletinj o ur n a l h o m e p a g e :w w w.e l se v i e r.c om /l oc a t e /m a t r e sb u0025-5408/$–see front matter ß2009Elsevier Ltd.All rights reserved.doi:10.1016/j.materresbull.2009.01.001X-ray diffractograms of the sintered samples were recorded using a Bruker diffractometer in the range 108 2u 708with CuK a radiation.The sintered pellets were polished to a thickness of 1mm and coated with silver paste on both sides for use as electrodes and cured at 5508C for half an hour.Electrical conductivity was performed using Keithley’s 6517A Electrometer.The polarization–electric field (P –E )hysteresis measurements were done at room temperature using an automatic P –E loop tracer based on Sawyer–Tower circuit.Piezoelectric charge co-efficient d 33was measured using a Berlincourt d 33meter after poling the samples in silicone–oil bath at 2008C for half an hour under a dc electric field of 60–70kV/cm.3.Results and discussion3.1.Structural and micro-structural studiesThe phase formation and crystal structure of the ceramics were examined by X-ray diffraction (XRD),which is shown in Fig.1.The XRD patterns of the samples show the characteristic peaks of SBT.The peaks have been indexed with the help of a computer program–POWDIN [21]and the refined lattice parameters are given in Table 1.It is observed that a single phase layered perovskite structure is maintained in the range 0.0 x 0.05.Owing to the same co-ordination number i.e.6and the smallerionic radius of W (0.60A˚)in comparison to Ta (0.64A ˚),there is a high possibility of tungsten occupying the tantalum site.The observance of unidentified peak of very low intensity in the compositions with x >0.05indicates the solubility limit of W concentration in SBT.The unidentified peak is possibly due to tungsten not occupying the Ta sites in the structure as the intensity of this peak is observed to increase with tungsten content.Composition and sintering temperature influences the micro-structure such as grain growth and densification of the specimen,which in turn control other properties of the material [11,13].The effects of W substitution on the microstructure have been examined by SEM and the obtained micrographs are shown in Fig.2.It shows the microstructure of the fractured surface of the studied samples.It is clearly observed that W substitution has pronounced effect on the average grain size and homogeneity of the grains.Randomly oriented and anisotropic plate-like grains are observed in all the samples.It is also observed that the average grain size increases gradually with increasing W content.The average grain size in the sample with x =0.0is $2–3m m while that in the sample with x =0.20the size increases to $5–7m m.3.2.Electrical studiesThe electrical conductivity of ceramic materials encompasses a wide range of values.In insulators,the defects w.r.t.the perfect crystalline structure act as charge carriers and the consideration of charge transport leads necessarily to the consideration of point defects and their migration [22].Many mechanisms were put forward to explain the conductivity mechanism in ceramics.Most of them are approximately divided into three groups:electronic conduction,oxygen vacancies ionic conduction,and ionic and p-type mixed conduction [22].Intrinsic conductivity results from the movement of the component ions,whereas conduction resulting from the impurity ions present in the lattice is known as extrinsic conductivity.At low temperature region (ferroelectric phase),the conduction is dominated by the extrinsic conduction,whereas the conduction at the high-temperature paraelectric phase ($300–7008C)is dominated by the intrinsic ionic conduction [23,25].Fig.3shows the temperature dependence of dc conductivity (s dc )for the undoped and doped SBT samples.The curves show that the conductivity increases with temperature.This is indicative of negative temperature coefficient of resistance (NTCR)behavior,a characteristic of dielectrics [22].It is observed in Fig.3that throughout the temperature range,the dc conductivity of the doped samples are nearly two to three orders lower than that of the undoped sample.Two predominant conduction mechanisms indicated by slope changes in the two different temperature regions are observed in Fig.3.Such changes in the slope in the vicinity of the ferro-paraelectric transition region have been observed in other ferroelectric materials as well [23,24].In addition,it is also observed (Table 2)that the activation energy calculated using the Arrhenius equation [22]in the paraelectric phase increase from $0.80eV for the undoped sample to $2eV for the doped samples.The X-ray photoemission spectroscopic study has confirmed that when Bi 2O 3evaporates during high-temperature processing,vacancy complexes are formed in the (Bi 2O 2)2+layers [26].As a result,defective (Bi 2O 2)2+layers are inherently present in SBT.The undoped SBT shows n-type conductivity,since when oxygen vacancies are created,it leaves behind two trapped electrons [27]:O o !12O 2"þV o þ2e 0(1)where O o is an oxygen ion on an oxygen site,V o is a oxygen vacant site and e 0represents electron.The conductivity in the perovskites can be described as an ordered diffusion of oxygen vacancies [28].Their motion is manifested by enhanced ionic conductivity associated with an activation energy value of $1eV [26].These oxygen vacancies can be suppressed by addition of donors,since the donor oxide contains more oxygen per cation than the host oxide it replaces [29].It has been reported that conductivity in Bi 4Ti 3O 12(BIT)can be significantly decreased,up to three orders of magnitude with the addition of donors,such as Nb 5+and Ta 5+at the Ti 4+sites [23,30].A few other studies on layered perovskites have also reported a decrease inconductivityFig.1.XRD patterns of SrBi 2(W x Ta 1Àx )2O 9samples sintered at 12008C.Table 1Lattice parameters of SrBi 2(W x Ta 1Àx )2O 9samples.Concentration of W a (A ˚)b (A ˚)c (A ˚)0.0 5.5212 5.513924.92230.025 5.5214 5.520225.10790.05 5.5217 5.519925.05850.075 5.5191 5.504525.05670.10 5.5142 5.506125.0850.205.51335.493925.0861I.Coondoo et al./Materials Research Bulletin 44(2009)1288–12921289with addition of donors [23,24,31].In the present study,the Ta 5+-site substitution by W 6+in SBT can be formulated using a defect chemistry expression as WO 3þV o!Ta 2O 512W Ta þ3O o (2)It shows that the oxygen vacancies are reduced upon the substitution of donor W 6+ions for Ta 5+ions.Hence,it is reasonable to believe that the conductivity in SBT is suppressed by donor addition.As per the above discussion,the high s dc observed in the undoped SBT (Fig.3)can be attributed to the motion of oxygen vacancies.As already discussed,the doped samples show reduced conductivity because the transport phenomena involving oxygen vacancies are greatly reduced.The high E a value of $1.75–2eVcorresponding to the high-temperature region in the doped ceramics is consistent with the fact that in the donor-doped materials,the ionic conduction reduces [32].The activation energy E a in the low temperature ferroelectric region (Table 2)corre-sponds to extrinsic conduction.At lower temperatures the extrinsic conductivity results from the migration of impurity ions in the lattice.Some of these impurities may also be associated with lattice defects.Pure SBT has large number of Schottky defects (oxygen vacancies)in addition to impurity ions whereas in the doped samples,due to charge neutrality,there is relatively less content of oxygen vacancies.Thus,in the doped samples the conductivity in the low temperature region is largely due to the impurity ions only.This explains the high activation energy in pure SBT in the low temperature region compared to doped samples (Table 2).In the high-temperature region,the value of E a in the doped samples is observed to increase with W concentration up to x =0.05but beyond that,it decreases (Table 2).The decrease in the activation energy for samples with x >0.05suggests an increase in the concentration of mobile charge carriers [33].This observation can be ascribed to the existence of multiple valence states of tungsten.Since tungsten is a transitional metal element,the valence state of W ions in a solid solution most likely varies from W 6+to W 4+depending on the surrounding chemical environment [34].When W 4+are substituted for the Ta 5+sites,oxygen vacancies would be created,i.e.one oxygen vacancy would be created for every two tetravalent W ions entering the crystal structure,whichFig.3.Variation of dc conductivity with temperature in SrBi 2(W x Ta 1Àx )2O 9samples.Fig.2.SEM micrographs of fractured surfaces of SrBi 2(W x Ta 1Àx )2O 9samples with (a)x =0.0,(b)x =0.025,(c)x =0.050,(d)x =0.075,(e)x =0.10and (f)x =0.20Table 2Activation energy (E a )in the high-temperature paraelectric region and low temperature ferroelectric region;Curie temperature (T c )in SrBi 2(W x Ta 1Àx )2O 9samples.Concentration of W E a (high temp.)(eV)E a (low temp.)(eV)T c (8C)0.00.790.893110.025 1.920.593080.05 1.960.543250.075 1.940.543380.10 1.860.573680.201.740.54390I.Coondoo et al./Materials Research Bulletin 44(2009)1288–12921290explains the increase in the concentration of mobile charge carriers which ultimately results in an decrease in the E a beyond x>0.05. Hence it is reasonable to conclude that W ions in the SBWT exists as a varying valency state,i.e.at lower doping concentration they exist in hexavalent state(W6+)and at a higher doping concentra-tion,they tend to exist in lower valency states[8].The P–E loops of SrBi2(Ta1Àx W x)2O9are shown in Fig.4.It is observed that W-doping results in formation of well-defined hysteresis loops.Fig.5shows the compositional dependence of remanent polarization(2P r)and the coercivefield(2E c)of SrBi2(Ta1Àx W x)2O9samples.Both the parameters depend on W content of the samples.It is observed that2P rfirst increases with x and then decreases while2E cfirst decreases with x and then increases(Fig.5).The optimum tungsten content for maximum2P r ($25m C/cm2)is observed to be x=0.075.It is known that ferroelectric properties are affected by compositional modification,microstructural variation and lattice defects like oxygen vacancies[10,35,36].In hard ferroelectrics, with lower valent substituents,the associated oxide vacancies are likely to assemble in the vicinity of domain walls[37,38].These domains are locked by the defects and their polarization switching is difficult,leading to an increase in E c and decrease in P r[38]. On the other hand,in soft ferroelectrics,with higher valent substituents,the defects are cation vacancies whose generation in the structure generally increases P r.Similar observations have been made in many reports[38–41].Watanabe et al.[42]reported a remarkable improvement in ferroelectric properties in the Bi4Ti3O12ceramic by adding higher valent cation,V5+at the Ti4+ site.It has also been reported that cation vacancies generated by donor doping make domain motion easier and enhance the ferroelectric properties[43].Further,it is known that domain walls are relatively free in large grains and are inhibited in their movement as the grain size decreases[44].In the larger grains, domain motion is easier which results in larger P r.Also for the SBT-based system,it is known that with increase in the grain size the remanent polarization also increases[45,46].Based on the obtained results and above discussion,it can be understood that in the undoped SBT,the oxygen vacancies assemble at sites near domain boundaries leading to a strong domain pinning.Hence,as observed,well-saturated P–E loop for pure SBT is not obtained.But in the doped samples,the suppression of the oxygen vacancies reduces the pinning effect on the domain walls,leading to enhanced remanent polarization and lower coercivefield.Also,the increase in grain size in tungsten added SBT,as observed in SEM micrographs(Fig.2)contribute to the increase in polarization values.In the present study,the grain size is observed to increase with increasing W concentration.However, the2P r values do not monotonously increase and neither the E c decreases continuously with increasing W concentration(Fig.5). The variation of P r and E c beyond x>0.05,seems possibly affected by the presence of secondary phases(observed in XRD diffracto-grams),which hampers the switching process of polarization [47–50].Also,beyond x>0.05the increase in the number of charge carriers in the form of oxygen vacancies leads to pinning of domain walls and thus a reduction in the values of P r and increase in E c is observed.Fig.6shows the variation of piezoelectric charge coefficient d33 with x in the SrBi2(Ta1Àx W x)2O9.The d33values increases with increase in W content up to x=0.05.A decrease in d33values is observed in the samples with x!0.075.The piezoelectric coefficient,d33,increases from13pC/N in the sample with x=0.0to23pC/N in the sample with x=0.05.It is known that the major drawback of SBT is its relatively higher conductivity,which hinders proper poling[51].High resistivity is therefore important for maintenance of poling efficiency at high-temperature[52,53].The W-doped SBT samples show an electrical conductivity value up to three orders of magnitude lower than that of undoped sample(Fig.3).The positional variation of2P r and2E c in SrBi2(W x Ta1Àx)2O9samples.Fig.6.Variation of d33in SrBi2(W x Ta1Àx)2O9samples.Fig. 4.P–E hysteresis loops in SrBi2(W x Ta1Àx)2O9samples recorded at roomtemperature.I.Coondoo et al./Materials Research Bulletin44(2009)1288–12921291decrease in conductivity upon donor doping improve the poling efficiency resulting in the observed higher d33values.Moreover, since the grain size increases with W content in SBT,it is reasonable to believe that the increase in grain size will also contribute to the increase in d33values[54].The decrease in the value of d33for samples with x!0.075is possibly due to the presence of secondary phases as observed in diffractograms[1,51,55]and the increase in oxygen vacancies for samples with x>0.05.4.ConclusionsX-ray diffractograms of the samples reveal that the single phase layered perovskite structure is maintained in the samples with tungsten content x0.05.SEM micrographs reveal that the average grain size increases with increase in W concentration. The temperature dependence of the electrical conductivity shows that tungsten doping results in the decrease of conductivity by up to three order of magnitude compared to W free SBT.All the tungsten-doped ceramics have higher2P r than that of the undoped sample.The maximum2P r($25m C/cm2)is obtained in the composition with x=0.075.The reduced conductivity allows high-temperature poling of the doped samples.Such compositions with low loss and high P r values should be excellent materials for highly stable ferroelectric memory devices.The d33value is observed to increase with increasing W content up to x0.05.The value of d33 in the composition with x=0.05is$23pC/N as compared to$13 pC/N in the undoped sample.AcknowledgmentsThe authors sincerely thank Prof.P.B.Sharma,Dean,Delhi College of Engineering,India for his generous support and providing ample research infrastructure to carry out the research work.The authors are thankful to Dr.S.K.Singhal,Scientist, National Physical 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陶瓷的英语专业术语摘要：这是一篇关于陶瓷的英语专业术语的文章，主要介绍了陶瓷的定义、分类、原料、工艺、类型、性能、装饰等方面的相关术语，并给出了中英文对照的表格。

文章的目的是帮助读者了解和掌握陶瓷领域的基本概念和专业词汇，以便于进行学习、交流和创作。

一、陶瓷的定义陶瓷（ceramics）是一种由无机非金属材料经过高温烧制而成的人造物品，具有硬度高、耐磨、耐高温、耐腐蚀等特点。

陶瓷是人类最早发明和使用的材料之一，历史悠久，文化丰富，艺术多样。

中文英文陶瓷ceramics无机非金属材料inorganic nonmetallic materials烧制firing硬度hardness耐磨wear-resistant耐高温high-temperature resistant耐腐蚀corrosion-resistant粘土clay二、陶瓷的分类根据陶瓷的成分、结构和性能，可以将其分为以下几类：传统陶瓷（traditional ceramics）：是指以天然粘土为主要原料，经过成型、干燥和低温或中温烧制而成的陶瓷，主要包括陶器（earthenware）、粗陶器（stoneware）、瓷器（porcelain）、玻璃（glass）等。

传统陶瓷通常具有多孔性（porosity）、不透明性（opacity）和低强度（low strength）等特征，主要用于日用器皿（tableware）、艺术品（artworks）、建筑材料（building materials）等领域。

特种陶瓷（special ceramics）：是指以高纯度的无机非金属化合物为主要原料，经过粉末冶金工艺和高温烧结而成的陶瓷，主要包括氧化物陶瓷（oxide ceramics）、非氧化物陶瓷（non-oxide ceramics）、复合陶瓷（composite ceramics）等。

特种陶瓷通常具有高强度（high strength）、高硬度（high hardness）、高耐热性（high heat resistance）和高耐蚀性（high corrosion resistance）等特征，主要用于电子器件（electronic devices）、机械零件（mechanical parts）、生物医学材料（biomedical materials）等领域。

冶金工程专业英语词汇1. 冶金学冶金学是冶金工程专业的核心课程，主要讲授钢铁冶金和有色金属冶金过程的基本原理、工艺及装备，包括炼铁、炼钢、精炼、连铸、铝冶金、铜冶金、稀土冶金等内容。

中文英文冶金学metallurgy钢铁冶金iron and steel metallurgy有色金属冶金nonferrous metal metallurgy炼铁ironmaking炼钢steelmaking精炼refining连铸continuous casting铝冶金aluminum metallurgy铜冶金copper metallurgy稀土冶金rare earth metallurgy高炉blast furnace转炉converter电炉electric furnace真空精炼vacuum refining钢包ladle结晶器crystallizer铝电解槽aluminum electrolytic cell铜闪速熔炼copper flash smelting稀土萃取分离rare earth extraction and separation熔盐电解法molten salt electrolysis method冶炼产品smelting products生铁pig iron钢水molten steel铝锭aluminum ingot铜阳极泥copper anode slime稀土氧化物rare earth oxides冶炼渣smelting slag炉渣性质slag properties脱硫desulfurization脱磷dephosphorization脱氧deoxidation合金化alloying溅渣护炉splashing slag lining protection终点控制endpoint control中文英文出钢操作tapping operation凝固传热机制solidification heat transfer mechanism凝固结构与缺陷solidification structure and defects氧化还原反应oxidation-reduction reaction造渣反应与造渣制度slagging reaction and slagging system2. 冶金物理化学冶金物理化学是冶金工程专业的基础理论课程，主要讲授冶金过程中涉及的物理化学原理和方法，包括平衡与相图、溶液理论、电化学、表面与胶体化学、传递现象等内容。

Dear Editor and Reviewers:On behalf of my co-authors, we are very grateful to you for giving us an opportunity to revise our manuscript. we appreciate you very much for your positive and constructive comments and suggestions on our manuscript entitled “Thermal Process and Mechanism of Phase Transition and Detoxification of Glass-ceramics from Asbestos Tailings” (ID: NOC-D-18-01200).We have studied reviewers’ comments carefully and tried our best to revise our manuscript according to the comments. The following are the responses and revisions I have made in response to the reviewers' questions and suggestions on an item-by-item basis. Thanks again to the hard work of the editor and reviewer!Response to the comments of Reviewer #1Comment No. 1: Page number should be included in the manuscript.Response:Thanks to Reviewer for reminder, we added the page number to the manuscript.Comment No. 2: Is it differential thermal analysis or differential scanning calorimetry? (Abstract)Response: The crystallization and phase change of the samples were investigated by thermogravimetry-differential scanning calorimetry (TG-DSC), and the results were shown in figure 2.Comment No. 3: Please clarify: "Asbestos tailings are tailings produced during the mining and beneficiation of chrysotile (fibrid asbestos)" Given the fact that chrysotile is carcinogenic please include in the Introduction part some aspects about health regulations/concerns to take care during synthesis of chrysotile containing materials. For instance, which is the safety/allowed threshold for chrysotile content in building materials? (Introduction)Response: It is really true as Reviewer mentioned that due to the hazards of chrysotile, the use of chrysotile containing materials have been banned completely in many countries, and for the recycling of chrysotile containing materials, there are some legal restrictions which I have added to the section of Introduction. There are some safety hazards in the synthesis and use of asbestos-containing materials inevitably, however this concern doesn't exist in our experiment, because the samples prepared in the experiment are completely free of asbestos, which is explained in the response to Reviewer#2 below.Comment No. 4: Magnification within 1000-500 range included in the experimental part, but x5000 magnification is met in Figs 6. (Experimental characterization) Response: We are very sorry for our negligence of mistakenly writing the magnification range as 500-1000 in the experimental characterization, actually the magnification range is 500-5000.Response to the comments of Reviewer #2Comment No. 1: Manuscript deals with transformation of unhealthy chrysotile (serpentine) into forsterite and /or enstatite-containing materials for decorative building purposes. However, chrysotile content of the obtained materials should be thoroughly controlled.Response: Thank you for your valuable comment, it is definitely a critical issue that chrysotile content of the obtained materials (glass-ceramics) should be thoroughly controlled. Actually, the chrysotile in serpentine starts at 600℃ and completely removes hydroxyl at 700℃ resulting the decomposition of original minerals and the disintegration of structure, and form harmless substances including amorphous silica and forsterite. So in the experiment, the fiber structure chrysotile can be completely destroyed after pre-firing at 700℃. Furthermore, in the thermal treatment of crystallization and sintering at higher temperatures, the residue that has not been completely decomposed can be further decomposed and totally converted into harmless phases including forsterite, enstatite, etc. by solid phase reaction and solid-liquid reaction. Ultimately, the product was entirely asbestos-free and which can be seen from the morphology of the samples in figure 6.Response to the comments of Reviewer #3Comment No. 1: Give some reference for the chemical content of Asbestos tailings for the benefit of the reader. (Introduction)Response: As Reviewer suggested that it is indeed better to give some reference for the chemical content of Asbestos tailings. Two reference (reference 2 and reference 3) were added to confirm the chemical content and phase composition of asbestos tailings. Comment No. 2: How do you distinguish between the main crystal phase and the subcrystalline phase?Response: we are sorry that we may have not expressed it clearly, the word “subcrystalline” used in my manuscript may be not accurate. I think it would be suitable to change it to the word “minor”. The content of different crystal phases in the sample were determined by rietveld refinement using GSAS, and the results are shown below (with the weight fraction of forsterite being 39.44%, enstatite 24.92%, diopside 21.18% and magnesioferrite14.45% respectively). According to the result, it can be seen that the main crystal phases are forsterite and enstatite, and the minor phases are diopside and magnesioferrite.Fig 1. Rietveld refinement of the sample crystallized at 850℃ and sintered at 1200℃Comment No. 3: English has to be immproved.Response : Considering the Reviewer’s suggestion, we will take great effort to modify the sentence to make it more professional. The portion of language modification are marked in green in the revised manuscript, and I hope it can meet with requirement. 10203040506070802 ( )R e l a t i v e i n t e n s i t y (a .u .) × ① ② ③ ④ CalcObsDiff ① ② ③ ④Forsterite 39.44%Enstatite 24.92% Diopside 21.18%Magnesioferrite 14.45%。

材料科学基础专业词汇：第二章晶体结构缺陷固溶体solid solution 固溶度solid solubility化合物compound 间隙固溶体interstitial solid solution 置换固溶体s ubstitutional 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Nonstoichiometriccompound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dislocationarrangement 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dislocationatmosphere 位错轴dislocation axis 位错胞dislocation cell 位错爬移dislocation climb 位错聚结dislocationcoalescence 位错滑移dislocation slip 位错核心能量dislocation coreenergy 位错裂纹dislocation crack 位错阻尼dislocation damping 位错密度dislocation density 原子错位substitution of awrong atom 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Kroger Vink notation 中性原子neutral atom材料科学基础专业词汇：第三章熔体结构体结构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m etastable phase 组织constitution淬火quenching 退火的softened玻璃分相phase separation inglasses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 grainboundary 大角度晶界high angle grainboundary共格孪晶界coherent twin boundary 晶界迁移grain boundarymigration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-coherentboundary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crystallographic orientation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热力学函数thermodynamicsfunction热分析thermal analysis过冷supercooling 过冷度degree ofsupercooling杠杆定律lever rule 相界phase boundary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Secondaryrecrystallization 成核nucleation 结晶crystallization 子晶，雏晶matted crystal 耔晶取向seed orientation异质核化heterogeneousnucleation 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 heattreatment。

第36卷 第4期 无 机 材 料 学 报Vol. 36No. 42021年4月Journal of Inorganic Materials Apr., 2021收稿日期: 2020-07-06; 收到修改稿日期: 2020-08-28; 网络出版日期: 2020-10-19基金项目: 国家自然科学基金青年基金(51802213); 山西省应用基础研究计划面上青年基金(201901D211118)National Natural Science Foundation of China (51802213); Program of Applied Basic Research Program of Shanxi Province (201901D211118)作者简介: 张丰年(1998–), 男, 硕士研究生.E-mail:*******************ZHANGFengnian(1998–),male,Mastercandidate.E-mail:*******************通信作者: 苗 洋, 副教授.E-mail:*****************.cn文章编号: 1000-324X(2021)04-0372-07 DOI: 10.15541/jim20200374高熵陶瓷(Zr 1/7Hf 1/7Ce 1/7Y 2/7La 2/7)O 2-δ的制备及烧结行为张丰年, 郭 猛, 苗 洋, 高 峰, 成楚飞, 程富豪, 刘宇峰(太原理工大学 材料科学与工程学院, 太原 030024)摘 要: 近年来, 不同体系的高熵陶瓷迅猛发展, 但萤石结构高熵氧化物仍处于研发初期。

本研究采用机械球磨和常压烧结的方法合成一种新型高熵萤石氧化物, 利用XRD, SEM, TG-DSC 和可视化形变分析仪研究了陶瓷的物相转变、表面形貌以及烧结行为。

研究结果表明, (Zr 1/7Hf 1/7Ce 1/7Y 2/7La 2/7)O 2-δ是一种非等摩尔的“高熵”陶瓷, 其内部各元素分布均匀。