XUJie ^1.2,ZHOU Xiaobing ²,XU Kai²,CHANG Keke ²,DAI Jianqing ¹,HUANG Oing ²

(1.Kunming University of Science and Technology,Kunming 650000,Yunnan,China;2.Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences, Ningbo 315000, Zhejiang, China)

Abstract: Low temperature sintering of highly dense SiC ceramics is one of the research focuses of scholars in industries, because of the high degree of Si-C covalent bonding and the low self-diffusion coefficient of SiC. Noting that low-temperature eutectic liquid phase transition between Pr₃Si₂C₂ and SiC can promote the sintering of SiC,PrsSi₂C₂ was grown in-situ on the surface of SiC particles by using a molten salt method,in order to ensure the uniform dispersion of Pr₃SizC₂ in the SiC particles. SiC ceramics with high density (porosity of 0.3%) and thermal conductivity of up to 106 W·m^-l·K^-l were successfully fabricated, by using electric current field-assisted sintering technology at a low temperature of 1500 ℃. According to microstructure of the SiC ceramics, it is concluded that the sintering process followed a typical solution-precipitated liquid phase sintering mechanism. Therefore,Pr₃Si₂C₂ is a promising low-temperature sintering additive for the low-temperature sintering of SiC ceramics and their composites.
Key words: SiC;liquid phase sintering; electric current field-assisted sintering;Pr₃Si₂C₂;molten salt