Microstructural and thermal property evolution of reaction bonded silicon carbide (RBSC)

Abstract Temperature dependent thermal conductivity of reaction bonded silicon carbide (RBSC) from 300 K to 1073 K is evaluated. The thermal conductivity of 80 vol% and 90 vol% SiC RBSC is measured to be 185.7 W/m·K and 211.4 W/m·K at room temperature and decreases to 51.46 W/m·K and 55.77 W/m·K at 1073 K, respectively. Thermal transport behavior of RBSC at elevated temperatures suggests that a structural mechanism plausibly associated with phase transformation occurs in the composite system. TEM in-situ heating test is employed to investigate the RBSC phase evolution. Results indicate the existence of minor Si amorphous phase near SiC/Si interface, and the amorphous Si phase transformation to crystalline Si could start at a relatively low temperature. The Si phase transformation improves the thermal transport performance of the RBSC system.