The Influence of Microstructure on Thermal Conductivity of SiC Liquid-Phase-Sintered with BeO Addition
Hiromi NAKANO, Koji WATARI, Kozo ISHIZAKI and Kazuyori URABE
Abstract:The thermal conductivity of SiC ceramics sintered with BeO exhibited a higher value of 270 W(mK)-1 at room temperature than that of the other non-oxide ceramics. We focused on the microstructure formed by addition of a small amount of BeO. TEM images revealed new microstructural data for understanding the thermal conductivity of this SiC ceramics. BeO addition in the SiC sintering formed a liquid phase, and densification of SiC ceramics was improved. A kind of very thin intergranular film existed as an amorphous state on the surfaces of almost all of the grains. During the liquid-phase sintering process, impurities of Fe, Ni, Al, V, Ti, and O were also precipitated at the triple-grain junction from the liquid phase. Key Words:Liquid phase sintering, Transmission electron microscopy, Grain boundaries, Thermal conductivity, Silicon carbide, Microstructure