Core-rim structure,bi-solubility and a hierarchical phase relationship in hot-pressed ZrB2-SiC-MC ceramics(M=Nb,Hf,Ta,W)  

作　　者：Dong-Li Hu Hui Gu Ji Zou Qiang Zheng Guo-Jun Zhang 

机构地区：[1]School of Materials Sciences and Engineering,Materials Genome Institute,Shanghai University,Shanghai,200444,China [2]State Key Laboratory of High Performance Ceramics and Superfine Microstructures,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai,200050,China [3]School of Metallurgy and Materials,University of Birmingham,B152TT,UK [4]CAS Key Laboratory of Standardization and Measurement for Nanotechnology,CAS Center for Excellence in Nanoscience,National Center for Nanoscience and Technology,Beijing,100190,China [5]State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Research Institute of Function Materials,Donghua University,Shanghai,201620,China

出　　处：《Journal of Materiomics》2021年第1期69-79,共11页无机材料学学报（英文）

基　　金：supported by the National Natural Science Foundation under Grants No.51532006;the Shanghai Municipal Science and Technology Commission under grant No.16DZ2260600;the 111 Project of the Ministry of Education and the National Bureau of Foreign Experts under grand No.D16002.

摘　　要：Core-rim structures were identified as a common feature in hot-pressed ZrB2-SiC-MC ceramics(M=Nb,Hf,Ta and W)by a combination of X-ray diffraction,scanning and transmission electron microscopies.Quantitative analyses associate them with the bi-solubility of M in ZrB2 phase,in which transition of solubility across the core/rim boundary is abrupted,signifying their creation via dissolution-reprecipitation process facilitated by transient liquid-phase.The cores were retained from starting powder after surface melting and the rims were grown from the liquid-phase to incorporate more solutes,leaving the residual liquid to turn into ZrC phase with higher solubility of M.We propose g-point scheme in the ZrB2-MB2 diagrams to combine the bi-solubility and the core-rim structures into an intra-phase relationship created by sintering,leading further to a hierarchical phase relationship.The temperature dependence of flexural strength in the ZrB2-SiC-MC ceramics varies with MC additions,which can be respectively strengthened by the strain energy created in the core-rim structures and metal segregation to grain boundaries.

关 键 词：Ultra-high-temperature ceramics Core-rim structures Bi-solubility Solution-reprecipitation process 

分 类 号：TQ174.1[化学工程—陶瓷工业]