Effects of concurrent grain boundary and surface segregation on the final stage of sintering: the case of Lanthanum doped yttriastabilized zirconia  

作　　者：M.M.Gong S.Dey L.J.Wu C.H.Chang H.Li R.H.R.Castro F.Liu 

机构地区：[1]State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China [2]Department of Materials Science ＆ Engineering, University of California, Davis, CA 95616, USA

出　　处：《Journal of Materials Science & Technology》2017年第3期251-260,共10页材料科学技术（英文版）

基　　金：support of the National Basic Research Program of China (No. 2011CB610403);the National Natural Science Foundation of China (Nos. 51134011 and 51431008);Research Fund of the State Key Laboratory of Solidification Processing (117-TZ-2015);the China National Funds for Distinguished Young Scientists (No. 51125002);supports of the Doctorate Foundation of Northwestern Polytechnical University (No. CX201204);support of the National Science Foundation (No. DMR 1055504)

摘　　要：Dopants play a critical role in tailoring the microstructure during sintering of compacts. These dopants may form solid solution within the bulk, and/or segregate to the grain boundaries（GBs） and the solidvapor interfaces（free surfaces）, each causing a distinct energetic scenario governing mass transports during densification and grain growth. In this work, the forces controlling the dopant distribution, in particular the possibility of concurrent segregation at both surfaces and GBs, are discussed based on the respective enthalpy of segregation. An equation is derived based on the minimum Gibbs energy of the system to determine enthalpy of segregation from experimental interface energy data, and the results applied to depict the role of La as a dopant on the interface energetics of yttria stabilized zirconia during its final stage of sintering. It is shown that La substantially decreases both GB and surface energies（differently）as sintering progresses, dynamically affecting its driving forces, and consequent grain growth and densification in this stage.Dopants play a critical role in tailoring the microstructure during sintering of compacts. These dopants may form solid solution within the bulk, and/or segregate to the grain boundaries（GBs） and the solidvapor interfaces（free surfaces）, each causing a distinct energetic scenario governing mass transports during densification and grain growth. In this work, the forces controlling the dopant distribution, in particular the possibility of concurrent segregation at both surfaces and GBs, are discussed based on the respective enthalpy of segregation. An equation is derived based on the minimum Gibbs energy of the system to determine enthalpy of segregation from experimental interface energy data, and the results applied to depict the role of La as a dopant on the interface energetics of yttria stabilized zirconia during its final stage of sintering. It is shown that La substantially decreases both GB and surface energies（differently）as sintering progresses, dynamically affecting its driving forces, and consequent grain growth and densification in this stage.

关 键 词：Grain boundary（GB） segregation Surface segregation Enthalpy of segregation GB energy Surface energy 

分 类 号：TB44[一般工业技术]