Preparation of SiC ceramics by aqueous gelcasting and

第52卷第8期2023年8月人㊀工㊀晶㊀体㊀学㊀报JOURNAL OF SYNTHETIC CRYSTALS Vol.52㊀No.8August,20236H to 3C Polytypic Transformation in SiC Ceramics During Brazing ProcessSHI Haojiang 1,ZHANG Ruiqian 1,LI Ming 1,YAN Jiazhen 2,LIU Zihao 2,BAI Dong 2(1.State Key Laboratory of Reactor Fuel and Materials,Nuclear Power Institute of China,Chengdu 610213,China;2.School of Mechanical Engineering,Sichuan University,Chengdu 610065,China)Abstract :In this paper,pure Ni foil was used as an intermediate layer to achieve brazing connection of 6H-SiC at 1100~1245ħ.The microstructure of the brazed joint and the interface between the brazed joint and the 6H-SiC substrate were studied to investigate the effect of brazing process on the crystal structure of SiC ceramics and provide theoretical and experimental data supports for brazing process design.The results show that a small amount of Ni atoms diffuse into the 6H-SiC ceramics during the brazing process and exist in solid solution form,which reduces the dislocation energy of 6H-SiC.The residual stress at the 6H-SiC /brazed joint interface increases with the increase of brazing temperature,and when the brazing temperature reaches 1245ħ,the (0001)plane of 6H-SiC at the interface slips along the 1/3<1100>direction,and the 6H-SiC is sheared to form 3C-SiC.Therefore,SiC ceramics can undergo phase transformation under the influence of stress and brazing material composition during the brazing process,and the effect of brazing process on their crystal structure and properties should be considered for SiC ceramics used in special environments.Key words :6H-SiC;3C-SiC;phase transformation;brazing;residual stressCLC number :O469㊀㊀Document code :A ㊀㊀Article ID :1000-985X (2023)08-1516-07SiC 陶瓷在钎焊过程中的6H 到3C 多型相变石浩江1,张瑞谦1,李㊀鸣1,颜家振2,刘自豪2,白㊀冬2(1.中国核动力研究设计院,反应堆燃料及材料国家重点实验室,成都㊀610213;2.四川大学机械工程学院,成都㊀610065)摘要:为探究钎焊过程对SiC 陶瓷晶体结构的影响,为钎焊工艺设计提供理论及试验数据支撑,本研究采用纯Ni 箔作为中间层在1100~1245ħ下实现了6H-SiC 的钎焊连接,并研究了焊缝以及6H-SiC 基体与焊缝界面处的微观形貌㊂研究结果表明,少量Ni 原子在钎焊过程中会扩散进入6H-SiC 陶瓷,并以固溶形式存在,降低了6H-SiC 层错能㊂随着钎焊温度升高,6H-SiC /焊缝界面处的焊后残余应力增大,当钎焊温度达到1245ħ时,界面处的6H-SiC 的(0001)面沿1/3<1100>方向产生滑移,6H-SiC 切变形成3C-SiC㊂因此,SiC 陶瓷在钎焊过程中受应力和钎料组成元素的作用发生相变,针对特殊环境使用的SiC 陶瓷需要斟酌钎焊工艺对其晶体结构及性能的影响㊂关键词:6H-SiC;3C-SiC;相变;钎焊;残余应力㊀㊀Received date :2023-01-03㊀㊀Foundation item :Research on Accident Tderant Fuel Technology for Nuclear Power (Phase Ⅱ)㊀㊀Biography :SHI Haojiang(1994 ),male,from Sichuan province,doctor,assistant research fellow.E-mail:myzxshj@ ㊀㊀Corresponding author :YAN Jiazhen,doctor,associate professor.E-mail:yanjiazhen@0㊀IntroductionSiC has a variety of crystal structures,such as hexagonal structure,cubic structure,and rhomboidal structure.Among them,the cubic SiC has only one stacking sequence,that is ABC ABC along the [0001]packing axis.SiC with this structure is called 3C-SiC,which is also known as β-SiC.All the other SiC crystals are collectively referred to as α-SiC.The hexagonal SiC with a stacking sequence of ABCACB along the packing axis is called 6H-SiC,㊀第8期SHI Haojiang et al:6H to3C Polytypic Transformation in SiC Ceramics During Brazing Process1517㊀and it is the most commonly seen SiC crystal in theα-SiC.SiC polytypes can transform to each other under certain conditions.Vlaskina et al[1-2]found that3C-SiC spontaneously transforms to6H-SiC at2000ħ.Parish et al[3]also observed the transformation from3C-SiC to6H-SiC at1440ħunder9dpa neutron irradiation.Due to the irradiation influence,the transformation temperature from3C-SiC to6H-SiC can be significantly reduced to1440ħ.In conclusion,β-SiC can transform toα-SiC through simple heat treatment at elevated temperatures. However,the transformation fromα-SiC toβ-SiC cannot be achieved by merely heat treatment.Zhu et al[4] investigated the deformation behavior and phase transformation in4H-SiC during nanoindentation process via molecular dynamics simulation.The simulation results show that it takes~9GPa of the shear stress for4H-SiC to transform to3C-SiC,where the atoms on(0001)plane of4H-SiC slips in1/3<1100>direction,resulting in the phase transformation from4H to3C.Yang et al[5]conducted a microindentation at1170ħwith a load of300g and a dwell time of30s on the6H-SiC,and the indented region shows that a6H to3C polytypic transformation occurs.The result confirms that SiC phase transformation can be induced by an applied stress.Based on the above investigations,a conclusion can be drawn that though it is difficult,the transformation fromα-SiC toβ-SiC is possible when enough stress is applied.Due to the significant differences in thermal conductivity,electrical conductivity,and radiation swelling resistance betweenα-SiC andβ-SiC,it is necessary for SiC ceramics to maintain structural stability in certain special service environments,such as structural materials in reactors and conductive materials in semiconductor components.Therefore studying the effect of the brazing process on the crystal structure of SiC ceramics is of great significance when SiC ceramics applications are often companied with joining.Nickel element is a common component element of SiC ceramic brazing fillers,and the reaction mechanism between nickel and SiC ceramic by a nickel foil as the brazing interlayer is reported in our previous work[6].In this paper,the polytypic transformation from6H-SiC to3C-SiC during brazing process is reported.The formation mechanism of the3C-SiC is investigated via HRTEM and SAED and well elaborated.1㊀Experimental sectionPressureless sintered6H-SiC ceramic blocks with dimension of15mmˑ10mmˑ5mm were brazed by a 0.1mm-thick pure nickel foil.The schematic diagram of the assembled SiC joint is shown in Fig.1(a).The detailed description about the SiC ceramics and nickel foil can be found in our previous work[6].The assembled specimens were heated to1100,1180,1245ħ,respectively,at a rate of15ħ/min with initial pressure of 3.5ˑ10-3Pa in vacuum furnace,and held for10min.Then the brazed samples were cooled down to room temperature in the furnace.The brazing heating curve is displayed in Fig.1(b).Fig.1㊀Schematic diagram of the assembled SiC joint(a)and the brazing heating curve(b)The detailed morphologies and compositions of the brazed seams were examined by field emission scanning electron microscope(FESEM,JSM-7500F)equipped with an energy dispersive spectrometer(EDS,Ultim Max). The EDS analysis using XPP correction method was operated under an accelerating voltage of15kV,a set of1518㊀研究论文人工晶体学报㊀㊀㊀㊀㊀㊀第52卷physical standards including SiO2,pure Ni and pure C are used for the analysis of element Si,Ni and C, respectively.Only the atomic fractions of Si and Ni are compared to characterize the reaction products in the joining seam due to the fact that carbon has low solubility in Ni-Si phases and can hardly be quantitatively analyzed.To further identify the phase structure of the joined seam,lift-out method is applied to the target location of interest using focused ion beam(FIB)on FEI Helios Nanolab600i.The thickness of the FIB sample decreases to50nm with a voltage range from2kV to30kV,and then analyzed by FEI Talos F200X and FEI Tecnai G2F20,operated at200kV,with an extreme field emission gun(X-FEG)electron source.The target FIB area locates at the interface between the transition zone and the6H-SiC.2㊀Results and discussionFig.2shows the microstructure of the SiC joints brazed at1100,1180,and1245ħ,respectively.As shown in Fig.2(b)and(d),the brazed seam and the6H-SiC ceramics are distinctly separated in the SiC joints brazed at1100and1180ħ.The interfaces are obvious and clear.When the brazing temperature increases to 1245ħ,the morphology of the interface changes,a transition zone forms between the brazed seam and the 6H-SiC.The transition zone consists of three phases,the island-likeδ-Ni2Si,scattered graphite flakes,and the 3C-SiC substrate[6].The chemical composition of the3C-SiC was analyzed under SEM mode,and the EDS results show that the mole fractions of C,Si and Ni in the target area are62.6%,35.7%and1.7%,respectively.The reaction process and mechanism between the nickel foil and6H-SiC can be found in our previous work[6].Fig.2㊀Microstructure of the SiC joints brazed at1100(a),(b),1180(c),(d),and1245ħ(e),(f)held for10min㊀第8期SHI Haojiang et al:6H to3C Polytypic Transformation in SiC Ceramics During Brazing Process1519㊀Fig.3shows the bright field images and corresponding HRTEM and SAED images of the FIB sample.3C-SiC, 6H-SiC andδ-Ni2Si are identified.EDS results are displayed in Table1.Notably,3C-SiC and6H-SiC both contain0.1%(atomic fraction)Ni.Since no nickel silicides are found in the3C-SiC and6H-SiC,Ni atoms should be ina form of solid solution atoms.Based on the HRTEM and SAED images after Fourier transform,it can be seen that 3C-SiC and6H-SiC share an obvious orientation relationship,the(0001)plane of the6H-SiC and the(111) plane of the3C-SiC are parallel to each other.The interface shown in Fig.3(f)is not crystallographically perfect, dislocations and terraces on(0110)6H plane can be found along the interface.The interface morphologies indicate that compared to the possibility of3C-SiC nucleating and growing on6H-SiC,it is more likely that3C-SiC is formed through the6H-SiC(0001)plane slipping along a specific direction.Table1㊀EDS analysis results of each area in Fig.3Location Composition/%Ni Si C Phase P10.135.964.06H-SiCP20.165.634.33C-SiCP368.032.0 δ-Ni2SiP465.035.0 δ-Ni2Si Transformation from6H-SiC to3C-SiC requires a certain shear stress applied on the slipping plane.As can be seen in Fig.2,no transition layer forms at the brazing temperature of1100and1180ħ,while it forms at a higher temperature of1245ħ.So it is highly possible that the shear stress comes from the residual stress that generates interface due to the CTE mismatch between the brazed seam and6H-SiC.The residual stress at the interface is estimated asσ=E S E RE S+E R(αR-αS)ΔT(1) whereσrepresents the residual stress,S stands for SiC,R stands for the reaction products near the interface,E represents the elastic modulus,αrepresents the linear expansion coefficient,andΔT represents the difference between the brazing temperature and the room temperature.The products near the interface are mainly Ni2Si and graphite,which are mixed up with each other and are uniformly distributed.So,the mixture of Ni2Si and graphite can be considered as a composite phase.The elastic modulus E of this composite phase is calculated according to the Voigt-Reuss formula[7]E composite=38E UL+58E LL(2)E UL=V N E N+V G E G(3)E LL=E G E NV N E G+V G E N(4) where N stands for Ni2Si,G stands for graphite,V and E stands for the volume modulus and elastic modulus, respectively.UL and LL represent the so-called upper and lower limit of the elastic modulus,respectively.The linear expansion coefficient of this composite phase is calculated using a more sophisticated formula,where the impact of stress is considered.The formula is written asαcomposite=αN V N K N+αG V G K GV N K N+V G K G(5) where V stands for volume fraction,K stands for the bulk modulus.Since graphite is anisotropic,therefore its morphology characteristics should be considered when selecting the physical property data of graphite.The graphite s physical properties along C axis are used since the graphite flake is nearly vertical to the brazed seam. All the physical properties used in these calculations are displayed in Table2.The results calculated according to1520㊀研究论文人工晶体学报㊀㊀㊀㊀㊀㊀第52卷the above formula show that the residual stress generated at the interface is1.76GPa when the joint cools down from1245ħ,and the residual stress is1.55GPa when the joint cools down from1100ħ.The residual stress increases with the increase of brazing temperature,providing a stronger force forα-SiC to transform.Fig.3㊀(a)TEM bright field image of the sample;(b),(c)HRTEM images of the3C/6H-SiC interface;(d)SAED image of the 3C/6H-SiC interface;(e),(f)higher magnification HRTEM images of the3C/6H-SiC interfaceTable2㊀Physical properties ofα-SiC,Ni2Si and graphite used in this paperPhase Elastic modulus,E/GPa Shear modulus,K/GPaCoefficient of linear expansion,α/(10-6K-1)Volume fraction/%α-SiC401.38[8]234[8] 3.5[8]Ni2Si168[9]189[9]13[10]51.3Graphite133.1[11]53.3[11]31[12]48.7 The calculated residual stress is much lower than the shear stress calculated by Zhu et al[4].However,there is no consensus on the critical value of stress thatα-SiC requires to transform toβ-SiC.Jepps et al[13]find that impurity element in SiC have a significant effect on the isomerism transition of SiC.When there are elements such as B and Al in SiC,α-SiC is more stable,andα-SiC can hardly transform toβ-SiC even under large shear stress. However,when the SiC contains N or P element,the stability ofβ-SiC is stronger,and only a small shear stress is required forα-SiC to transform toβ-SiC.Whitney et al[14]conducts a same experiment with the same conditions as Sokhor et al[15]reports,but fail to reproduce theα-SiC toβ-SiC transformation under the ambient pressure of3~7GPa at1200~1400ħ.But after Whitney et al adds BN intoα-SiC,the transformation fromα-SiC toβ-SiC occurred under the same circumstance.Therefore,impurity element has a significant effect on the(0001)6H slip activation energy ofα-SiC.As mentioned before,the presence of Ni element in SiC near the interface is confirmed,the existence of Ni should lower the magnitude of the residual stress thatα-SiC needs to transform toβ-SiC.Yuryeva et al[16-17] investigates the influence of Ni as an impurity element on the Si C bonding energy using first-principles calculations.They find that regardless of whether Ni exists in the form of a substitutional atom,an interstitial atom, or a more complex defect in SiC,the Si and C atoms around Ni atom are slightly displaced,resulting in the obvious weakening of the binding energy of the Si C covalent bond.This means that the isomeric transformation of SiC㊀第8期SHI Haojiang et al:6H to 3C Polytypic Transformation in SiC Ceramics During Brazing Process 1521㊀becomes easier.As shown in Fig.4,twins are found in the transformed SiC near the interface.The formation of twins in β-SiC indicates low stacking fault energy,which provides a high possibility for α-SiC to transform to β-SiC through (0001)6H plane sliding along the 1/3<1100>direction during the cooling process,turning the stackingsequence of ABCACB into ABCABC,as shown in Fig. 5.Fig.4㊀(a)TEM bright field image of the sample;(b),(c)HRTEM images of the twin grain in the 3C-SiC;(d)corresponding FFT pattern of the twin grain in the3C-SiCFig.5㊀HRTEM images of 6H-SiC (a)and 3C-SiC (b),and the schematic diagram of 6H-SiC transforming to 3C-SiC (c)1522㊀研究论文人工晶体学报㊀㊀㊀㊀㊀㊀第52卷3㊀ConclusionThe change of the SiC crystal structure during brazing process was investigated,and a polytypic transformation of6H-SiC to3C-SiC is reported in this paper.When6H-SiC ceramics was brazed using a0.1mm-thick pure nickel foil as the interlayer at1245ħ,the transformation of6H-SiC to3C-SiC is observed near the interface between the brazed seam and ceramic substrate.The microstructure and chemical composition of transformed SiC was analyzed and the6H-SiC to3C-SiC transformation mechanism is summarized as follow:1)A slight amount of Ni element exsists in the6H-SiC in a form of solid solution atom,and weakens the Si C bonding energy,lowering the stacking fault energy of6H-SiC.2)The CTE mismatch between the6H-SiC substrate and the brazed seam leads to residual stress after brazing, which drives the(0001)6H plane to slide along1/3<1100>direction,turning6H-SiC into3C-SiC.3)The brazing parameters and fillers should be carefully selected when brazing SiC for sophisticated applications since SiC polytypic transformation may occurs during the brazing process.References[1]㊀VLASKINA S I.3C-6H transformation in heated cubic silicon carbide3C-SiC[J].Semiconductor Physics Quantum Electronics andOptoelectronics,2011,14(4):432-436.[2]㊀VLASKINA S I,BUSINKAA@MAIL RU E M.Silicon carbide phase transition in as-grown3C-6H polytypes junction[J].Semiconductor PhysicsQuantum Electronics and Optoelectronics,2013,16(2):132-135.[3]㊀PARISH C M,KOYANAGI T,KONDO S,et al.Irradiation-inducedβtoαSiC transformation at low temperature[J].Scientific Reports,2017,7:1198.[4]㊀ZHU B,ZHAO D,ZHAO H W.A study of deformation behavior and phase transformation in4H-SiC during nanoindentation process viamolecular dynamics simulation[J].Ceramics International,2019,45(4):5150-5157.[5]㊀YANG J W,PIROUZ P.Theαңβpolytypic transformation in high-temperature indented SiC[J].Journal of Materials Research,1993,8(11):2902-2907.[6]㊀SHI H J,CHAI Y D,LI N,et al.Interfacial reaction mechanism of SiC joints joined by pure nickel foil[J].Journal of the European CeramicSociety,2020,40(15):5162-5171.[7]㊀GUZMÁN DE VILLORIA R,MIRAVETE A.Mechanical model to evaluate the effect of the dispersion in nanocomposites[J].Acta Materialia,2007,55(9):3025-3031.[8]㊀SENGUPTA P,SAHOO S S,BHATTACHARJEE A,et al.Effect of TiC addition on structure and properties of spark plasma sintered ZrB2-SiC-TiC ultrahigh temperature ceramic composite[J].Journal of Alloys and Compounds,2021,850:156668.[9]㊀ZHAO Y H,HOU H,ZHAO Y H,et al.First-principles study of the nickel-silicon binary compounds under pressure[J].Journal of Alloys andCompounds,2015,640:233-239.[10]㊀GEENEN F A,KNAEPEN W,MOENS F,et al.Anisotropic thermal expansion of Ni,Pd and Pt germanides and silicides[J].Journal of PhysicsD:Applied Physics,2016,49(27):275307.[11]㊀KIEWEL H,BUNGE H J,FRITSCHE L.Effect of orientation correlation on the elastic constants of polycrystalline materials[J].Textures andMicrostructures,1996,28(1/2):105-120.[12]㊀KELLY B T,WALKER P L.Theory of thermal expansion of a graphite crystal in the semi-continuum model[J].Carbon,1970,8(2):211-226.[13]㊀JEPPS N W,PAGE T F.Polytypic transformations in silicon carbide[J].Progress in Crystal Growth and Characterization,1983,7(1/2/3/4):259-307.[14]㊀WHITNEY E D,SHAFFER P T B.Investigation of the phase transformation between alpha-and beta-silicon carbide at high pressures[J].HighTemperatures-High Pressures,1969,1(1):107-110.[15]㊀SOKHOR M I,KONDAKOV V G,FELDGUN L I.Transition of silicon carbide from the hexagonal to the cubic phase under the influence of highpressures and high temperatures[J].Soviet Physics Doklady,1967,175(4):826.[16]㊀MEDVEDEVA N I,YURYEVAÉI,IVANOVSKII A L.Titanium,vanadium,and nickel impurities in3C-SiC:electronic structure and latticerelaxation effects[J].Semiconductors,2002,36(7):751-754.[17]㊀YURYEVA E I,IVANOVSKII A L.Electronic structure and chemical bonding of nickel impurities in cubic silicon carbide[J].Russian Journalof Coordination Chemistry,2002,28(12):881-888.。

英文文献信息检索方法和步骤013409108 陈真利用学校图书馆外文数据库SpringerLink进行英文文献检索的步骤：1、打开学校图书馆网页，点击数据库服务中的西文数据库，进入后再点击《Springer Link》数据库，进入SpringerLink数据库网页。

2、进入SpringerLink数据库网页后，找到“Advanced Search”标志，点击后出现一个界面框。

3、在界面框中的“Content”下框中输入“Porous ceramic”，再选择“Title Only”。

选择日期，先点击“Publication Dates Between”，然后再设定日期为01/01/2010到15/04/2012。

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4、进入页面后将会出现很多英文论文，在第三页选择一篇名为“Preparation ofmullite bonded porous SiC ceramics by an infiltration method”的文章，点击文章题目进入。

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6、摘要内容和翻译如下：Abstract :A powder compact of α-SiC and α-Al2O3 was infiltrated with a liquid precursor of SiO2, which on subsequent heat treatment at 1500 °C produced a mullite bonded porous SiC ceramics. Results showed that infiltration rate could be estimated by using weight gain measurements and theoretical analysis. The bond phase was composed of needle-shaped mullite which was observed to be grown from a siliceous melt formed during the process of oxide bonding. The porous SiC ceramics exhibited a density andporosity of 2 g.cm−3 and 30 vol%, respectively, and also a pore size distribution in a range of 2–15 μm with an average pore size of 5μm. No appreciable degradation of room temperature flexural strength (51 MPa) was observed at high temperatures (1100 °C).翻译：题目：渗透法制备莫来石结合碳化硅多孔陶瓷摘要：用二氧化硅的液态先驱体渗透由α-碳化硅和α-氧化铝混合的粉饼，然后放在1500℃的条件下进行热处理，就可以制备出莫来石结合的碳化硅的多孔陶瓷。

以松木和枇杷为模板低温烧结制备木材陶瓷李健;孟邦月;杨远大【摘要】以松木和枇杷为模板,炭化后浸渍聚碳硅烷(PCS溶液),在低温下烧结制备出木材陶瓷,并分析了PCS浓度对其烧结制品重量、线收缩率、体积密度和微观形貌的影响.结果表明采用松木和枇杷为模板,浸渍PCS有机溶液,能够在1000C低温下烧结出具有原始生物形貌的木材陶瓷.【期刊名称】《贵州科学》【年(卷),期】2019(037)002【总页数】4页(P78-81)【关键词】松木;枇杷;聚碳硅烷;低温烧结;木材陶瓷【作者】李健;孟邦月;杨远大【作者单位】贵州师范大学材料与建筑工程学院,贵州贵阳550014;贵州师范大学材料与建筑工程学院,贵州贵阳550014;贵州师范大学材料与建筑工程学院,贵州贵阳550014【正文语种】中文【中图分类】TQ1740 引言木材陶瓷是一种新型环境友好型陶瓷材料，将废弃生物材料(如：废纸、废木材、废竹材、甘蔗渣等)制成陶瓷，不仅减少环境污染，且成本低、适用性强，而且木材属于可再生能源，来源广、易降解。

木材陶瓷具有质轻、多孔性、强度高、电学和磁学性能良好、抗热冲击强、耐磨、耐腐蚀、膨胀系数小等优异性能[1]，因而木材陶瓷可应用于材料、电子、化工等多个领域[2]。

钱军民[3]、余先纯[4]、李淑君[5]等人分别从原材料、制备工艺、基本结构、物相构成等方面做了较细致的研究。

本实验以松木和枇杷为模板，采用浸渍法[6]经过预处理、炭化、挂浆、低温烧结等步骤制得木材陶瓷，并研究了最终产物的失重率、线收缩率、体积密度以及PCS浓度对物相结构、微观形貌等性能的影响。

1 实验内容1.1 实验流程图1 制备木材陶瓷的实验路线Fig.1 Experimental route of preparation of wood ceramics1.2 模板的预处理将收集到的松木和枇杷切成形状大小相等的块状。

将切割好的模板放入烘箱中以随炉升温的方式加热到170℃，干燥4 h，取出放入托盘中冷却。

表面技术第51卷第3期多孔SiC表面WC+W2C涂层的制备及其结构研究刘琪，桑可正，曾德军（长安大学 材料科学与工程学院，西安 710064）摘要：目的改善金属与SiC的润湿性，避免金属熔渗过程中损伤多孔SiC基体。

方法采用氧化烧结法制备了多孔SiC基体，再采用溶胶氢还原法于900 ℃在多孔SiC表面制备了WC+W2C涂层。

通过X射线衍射仪和扫描电子显微镜研究了涂层的结构和组成，以及热处理温度、时间和溶胶吸收次数对涂层的影响。

结果热处理温度为900~1100 ℃时，W与C发生反应并形成了WC与W2C，但温度增加至1350 ℃时，涂层与基体发生反应，形成了WSi2化合物。

在900 ℃时，随着热处理时间从1 h增加至3 h，涂层颗粒聚集长大，颗粒之间的距离增加。

随着吸胶次数的增加，经还原后的涂层颗粒数量增多，平均粒径不断增加，吸胶5次后，涂层颗粒所占表面区域面积百分比达到饱和，约为40%。

吸胶6次后，涂层颗粒的平均粒径达到0.53 μm。

结论 WC+W2C涂层以颗粒状分布在基体表面形成涂层。

通过增加吸胶次数到6次，可以有效地增加涂层颗粒的数量以及所占面积百分比。

基于涂层与金属润湿效果的最佳工艺条件是在试样吸胶6次后进行还原热处理，还原温度为900 ℃，时间为1 h。

关键词：润湿性；溶胶凝胶；碳化硅；涂层；WC+W2C中图分类号：TG174.44 文献标识码：A 文章编号：1001-3660(2022)03-0226-08DOI：10.16490/ki.issn.1001-3660.2022.03.024Preparation and Structure of WC+W2C Coating on Porous SiC SurfaceLIU Qi, SANG Ke-zheng, ZENG De-jun(School of Materials Science and Engineering, Chang'an University, Xi'an 710064, China)ABSTRACT: To improve the wettability of the metal with SiC and to avoid damage to the porous SiC substrate during the infiltration process. A certain amount of SiC powder was mixed with about 5wt.% alcohol-soluble phenolic resin. Then, the ϕ15 mm×4 mm specimens were obtained by cold pressing with 84 MPa press for 1 min. Finally, porous SiC substrates were prepared by oxidation sintering. The raw materials were prepared according to the mass ratio of ammonium metatungstate, citric acid, ethylene glycol and water-soluble phenolic resin 6 : 3 : 2 : 0.84. By adjusting the heating time to control the evaporation of收稿日期：2021-09-26；修订日期：2021-12-30Received：2021-09-26；Revised：2021-12-30基金项目：陕西省自然科学基金研究计划项目（2018JQ5120）Fund：Shaanxi Provincial Natural Science Foundation Research Program Project (2018JQ5120)作者简介：刘琪（1996—），男，硕士研究生，主要研究方向为先进陶瓷及其复合材料。

性能分析PROPERTY ANALYSIS航空制造技术·2009年增刊118[摘要] 以碳纤维整体毡为预制体，采用化学气相渗透法（CVI ）制备出低密度碳/碳复合材料，再分别采用液相硅渗透工艺（LSI ）制备出密度为2.1g/cm 3的碳/碳-碳化硅复合材料（C/C -SiC ），及先驱体转化工艺（PIP ）制备出密度为1.9g/cm 3的C/C -SiC 。

对2种工艺制备的C/C -SiC 力学性能进行了比较，结果表明：PIP 工艺制备的C/C -SiC 弯曲强度为287MPa ，明显高于LSI 工艺制备的弯曲强度155MPa 。

关键词: C/C-SiC 液相硅渗透工艺 先驱体转化工艺 化学气相渗透工艺[ABSTRACT] The C/C composites of low density are fabricated by chemical vapor in fi ltration (CVI) with in-tegral carbon felts with carbon fi ber as prefab. On the basis of the low density C/C composites, the C/C-SiC compos-ites with the density of 2.1g/cm 3 are prepared by liquid sili-con in fi ltration (LSI), and the C/C-SiC composites with the of density 1.9g/cm 3 are prepared by precursor infiltration and pyrolysis (PIP). The result shows that bend strength of the C/C-SiC composites prepared by PIP is 287MPa, which is better than that of 155MPa of the composites prepared by LSI.Keywords: C/C-SiC LSI PIP CVI碳纤维增强碳化硅陶瓷基复合材料（C/SiC ）因具有高强度、高硬度、抗氧化、抗蠕变以及高温下抗磨损性好、耐化学腐蚀性优良、热膨胀系数和相对密度较小等特点，在航空航天等高温热结构材料方面有着广泛的应用前景[1-2]。

第48卷第9期2020年9月硅酸盐学报Vol. 48，No. 9September，2020 JOURNAL OF THE CHINESE CERAMIC SOCIETY DOI：10.14062/j.issn.0454-5648.20190720发泡法制备莫来石多孔陶瓷吴文浩，张海军，葛胜涛，李赛赛，张少伟(武汉科技大学，省部共建耐火材料与冶金国家重点实验室，武汉 430081)摘要：以碳化硅及碳酸钙为造孔剂，采用发泡–注凝成型结合添加造孔剂法制备了具有大孔–介孔复合孔结构的莫来石多级孔陶瓷，研究了SiC加入量对莫来石多孔陶瓷常温物理性能和高温隔热性能的影响。

结果表明：以莫来石粉体为主要原料，以CaCO3和SiC为造孔剂，采用发泡结合添加造孔剂法可制备具有较高闭气孔率的莫来石多孔陶瓷；当SiC加入量为4%(质量分数)时，所制备试样的导热系数最低，其孔隙率约为69.9%。

关键词：莫来石；多级孔陶瓷；发泡–注凝成型法；造孔剂中图分类号：TQ174 文献标志码：A 文章编号：0454–5648(2020)09–1353–07网络出版时间：2020–07–13Preparation of Mullite Ceramics by Foam–Gelcasting MethodWU Wenhao, ZHANG Haijun, GE Shengtao, LI Saisai, ZHANG Shaowei(The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China)Abstract: Hierarchical pore structure mullite ceramics with macro– and meso-pores were prepared by a foam–gelcasting method and a pore-forming agent method using SiC and CaCO3 as additives. The effect of SiC amount on the flexural strength, compressive strength and thermal conductivities of porous ceramics was also investigated. The results show that porous mullite ceramics with a lot of close pores can be fabricated via the method with mullite powder as a raw material and CaCO3 and SiC (0–8% (mass fraction)) as additives. The as-synthesized porous mullite ceramic prepared with 4% (mass fraction) SiC has 69.9% porosity and a lowest thermal-conductivity.Keywords: mullite; hierarchical porous ceramics; foam–gelcasting; porerforming agent莫来石多孔陶瓷(MPC)由于具备熔点高、热膨胀系数小及热导率较低等卓越特性[1–5]，是隔热、催化及气体净化等领域的理想材料[6–8]。

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万方数据　万方数据　万方数据　万方数据　万方数据以硝酸铝为原料制备铝溶胶的研究作者：吴建锋， 徐晓虹， 张欣， Wu Jianfeng， Xu Xiaohong， Zhang Xin作者单位：武汉理工大学材料科学与工程学院,430070刊名：陶瓷学报英文刊名：JOURNAL OF CERAMICS年，卷(期)：2007,28(3)被引用次数：5次参考文献(15条)1.韦奇;张书根溶胶-凝胶法制备无机陶瓷膜 1998(08)2.A Larbot;L P Fabre;C Cvizard Inorganic Membraned Obtained by Sol-Gel Techniques 19883.戴树桂环境化学 20014.夏长荣;唐晔PVA修饰的sol-gel法制备γ-Al2O3超滤膜 1999(03)5.李月明;周健儿以无机盐为前驱体制备超滤膜的研究[期刊论文]-陶瓷学报 2002(06)6.W M Zeng;L Gao;J K Guo A new sol-gel route using inorganic salt for synthesi-zing Al2O3 nanopowders 1998(10)7.Edisson Morgado;YiuLau Lam Formation of Peptizable Boehrmites by Hydrolysis of Aluminum Nitrate in Aqueous Solution 19978.华彤文;高月英;赵凤林大学化学基础 20039.李月明;周健儿溶胶-凝胶法制备Al2O3钠米粉[期刊论文]-中国陶瓷 2002(05)10.贾之慎;张仕勇无机及分析化学 200411.周祖康;顾惕人;马季铭胶体化学基础 198712.姚楠;熊国兴;张玉红溶胶-凝胶法制备中孔分布集中的氧化物及混合氧化物催化材料[期刊论文]-中国科学B辑2001(04)13.R Petrovic;S Milonjic;V Jokanovic Influnence of synthesis parameters on the structure of boehmite sol particles 2003(133)14.M Zhou;J M F Ferreira Hydrothermal Ageing Effects on the Coprecipitated Mullite-Alumina composite Precursor[外文期刊] 1997(17)15.Kiyoshi Okada;Toru Nagashima;Yoshikazu Kameshima Relationship between FormationConditions,Properties,and Crystallite Size of Boehmite[外文期刊] 2002(2)本文读者也读过(8条)1.吴建锋.徐晓虹.张欣以硝酸铝为原料制备铝溶胶的研究[会议论文]-20072.季晓玲.翟丽莉.王珍一种铝溶胶的快速制备方法[期刊论文]-应用化工2009,38(8)3.尹忠亮铝溶胶生产工艺条件的研究[期刊论文]-精细石油化工进展2003,4(6)4.王黔平.郭琳琳.田秀淑.Wang Qianping.Guo Linlin.Tian Xiushu无机盐和醇盐先躯体制备铝溶胶及铝系无机膜的比较[期刊论文]-陶瓷2007(12)5.谢安建.沈玉华.黄方志.费菲铝溶胶的制备及影响因素的研究[期刊论文]-安徽化工2003,29(4)6.杨立英.李成岳.刘辉金属基体上铝溶胶涂层的制备[期刊论文]-催化学报2004,25(4)7.戴静.于长凤.朱小平.Dai Jing.Yu Changfeng.Zhu Xiaoping硅溶胶、铝溶胶在陶瓷原位胶态成形中的应用[期刊论文]-中国陶瓷工业2006,13(6)8.叶青.王道.周志清.金钧.周克斌.张颖氧化铝溶胶及涂层研究 I 氧化铝溶胶的性质[期刊论文]-北京工业大学学报2002,28(1)引证文献(5条)1.裴立宅铝、铝硅溶胶及其粉末的合成[期刊论文]-佛山陶瓷 2010(4)2.曹大勇不同扩孔方法对Al2O3/堇青石载体结构的影响[期刊论文]-化学工程师 2009(7)3.季晓玲.翟丽莉.王珍一种铝溶胶的快速制备方法[期刊论文]-应用化工 2009(8)4.刘惠平.朱鹏.刘章蕊.周波建筑用竹制脚踏板的防火阻燃[期刊论文]-消防科学与技术 2012(1)5.杨文建.王康.王希涛铝溶胶的制备条件对其凝胶成球性能的影响[期刊论文]-化学工程 2012(9)引用本文格式：吴建锋.徐晓虹.张欣.Wu Jianfeng.Xu Xiaohong.Zhang Xin以硝酸铝为原料制备铝溶胶的研究[期刊论文]-陶瓷学报 2007(3)。

第 4 期第 34-42 页材料工程Vol.52Apr. 2024Journal of Materials EngineeringNo.4pp.34-42第 52 卷2024 年 4 月ZrO 2增强聚合物先驱体SiCNO 复合陶瓷的制备和力学性能Preparation and mechanical properties of ZrO 2-reinforced polymer -derived SiCNOcomposite ceramics费轩，余煜玺*，严远高，魏永金，赵刚，黄柳英*（厦门大学 材料学院 福建省特种先进材料重点实验室，福建 厦门 361005）FEI Xuan ，YU Yuxi *，YAN Yuangao ，WEI Yongjin ，ZHAO Gang ，HUANG Liuying *（Fujian Key Laboratory of Advanced Materials ，College of Materials ，Xiamen University ，Xiamen 361005，Fujian ，China ）摘要：聚合物先驱体陶瓷（polymer -derived ceramics ，PDCs ）技术具有制造简单、成分可调等优点，为制备新型陶瓷提供了有效途径。

然而，由于热解过程中微小分子的逃逸形成孔洞缺陷，先驱体技术制备的无定形聚合物衍生SiCNO 陶瓷（PDCs -SiCNO 陶瓷）的力学性能较差。

为解决上述问题，通过向陶瓷基体添加第二相（颗粒强化）来实现增强先驱体陶瓷。

对聚乙烯基硅氮烷（PVSZ ）和ZrO 2进行先球磨后热解，制备ZrO 2颗粒增强PDCs -SiCNO 复合陶瓷（PDCs -SiCNO -ZrO 2），研究PDCs -SiCNO -ZrO 2复合陶瓷的结构和力学性能。

结果表明：引入的ZrO 2填料作为增强体嵌入SiCNO 陶瓷基体中，不仅能有效降低线收缩率，还能大幅提高PDCs -SiCNO -ZrO 2复合陶瓷的力学性能。

S1C多孔陶瓷的研究与制备江超余少华余开明(中国轻工业陶瓷研究所江西景德镇333000)摘要采用添加造孔剂法制备SiC多孔陶瓷。

笔者研究了2种造孔剂对多孔陶瓷的吸水率、气孔率、体积密度以及抗折强度的影响，还研究了4种烧成温度对SiC多孔陶瓷的性能影响。

实验结果表明：当配方组成为SiC85%、苏州土5%、造孔剂10%,外加5%的PVA,在20MPa的压力下干压成形，于四组不同温度下烧成，在1280C下，10%的木屑和炭粉分别作为造孔剂的SiC多孔陶瓷的气孔率为32.37%和40.21%,其中以10%的木屑为造孔剂的SiC多孔陶瓷抗折强度可达55.29MPa。

关键词SiC多孔陶瓷造孔剂性能中图分类号:TQ174.75文献标识码:A文章编号：1002—2872(2020)12—0029—04Research And Preparation of SiC Porous CeramicsJIANG t Chao,YU Shaohua,YU Kaiming(Ceramic Research Institute of Light Industry of China,Jiangxi,Jingdczhcn, 333000,China)Abstract：SiC porous ceramics were prepared by adding porosity agent.'The effects of two kinds of pore making agents on waterabsorption,porosity,volumedensityandflexuralstrengthofporousceramicswerestudied.Thee f ectsoffourfiring temperaturesonthepropertiesofSiCporousceramicswerealsostudied.Experimentalresultsshowthatwhentheformula composition of SiC85%,Suzhou soil,pore—forming agent10%,5%and5%of PVA,under the pressure of20MPa dry pressing molding,in four groups of firing at different temperatures and under1280°C,10%of sawdust and coal powder as pore—forming agent,respectively,the porosity of porous SiC ceramics were32.37%and40.31%,of which10%of saw dustaspore—formingagentoftheSiCporousceramicsflexuralstrengthof55.29MPa.Keywords:SiCporousceramics;Poreformer;Performance前言SiC多孔陶瓷是一种内部结构中有很多气孔的新型功能材料。