Sintering Behavior and Properties of Si3N4 Ceramics with Yttrium Chloride Additive
The big gap between the thermal conductivity of Si3N4 ceramics and the theoretical value of beta-Si3N4 single crystal implies that the low thermal conductive oxide grain-boundary phases in the ceramics possibly have a great influence on the thermal conductivity of the ceramics.In this work,yttrium chloride (YOCl) is introduced as sintering additive instead of the commonly-used Y2O3,in order to decrease the amount of the grain-boundary oxide; and the influence of YOCl on the sintering and the properties of Si3N4 ceramics was studied.Results show that YOCl additive can react with Si3N4 powders to form similar Y-Si-O-N grain-boundary phases just like Y2O3 while the Cl disappears during sintering.The thermal conductivity of the ceramics sintered with YOCl additive (85 W/m·K) increases about 15% as comparing with the ceramics sintered with Y2O3 additive,even though the relative density of the former reaches merely 97%.The microstructure of the sample sintered at different temperatures was investigated in the work,for elucidating the sintering process and the relationship between the properties and the microstructure of the YOCl added ceramics.
Si3N4 ceramics Yttrium chloride Thermal conductivity
Du Lu Xiaoshan Ning Kexin Chen Heping Zhou
State Key Laboratory of New Ceramics and Fine Processing,Department of Material Science and Engineering,Tsinghua University,Beijing 100084,China
国际会议
The Seventh China International Conference on High-Performance Ceramics (第七届先进陶瓷国际研讨会(CICC-7))
厦门
英文
841-848
2011-11-04（万方平台首次上网日期，不代表论文的发表时间）