Increasing the thermal conductivity of 2D SiC/SiC composites by heat-treatment

Effect of heat-treatment on the thermal conductivity of 2D SiC/SiC composites was investigated. Results showed that the thermal conductivity of SiC/SiC (9.8 W/(m K) at room temperature) increased by 194% as increasing the heat-treatment temperature from room temperature to 1700 °C. After treated at 1900 °C, the thermal conductivity increased 14 times from 9.8 W/(m K) (untreated) to 138.4 W/(m K). X-ray diffraction analysis and microstructural observation confirmed grain size of SiC matrix and SiC fiber were increased, meanwhile, with the increase of heat-treatment temperature, the distance between fiber and matrix enlarged from 0.5 μm (1300 °C) to ∼1.4 μm (1700 °C). The heat-treatment mainly influenced grain size of SiC matrix, the crystallinity of SiC fiber and the bounding status between fibers and matrix, which were very critical to the thermal conductivity of composites.