Transverse thermal conductivity of thin C/SiC composites fabricated by slurry infiltration and pyrolysis

Thin C/SiC composites were fabricated by infiltrating a woven carbon fiber fabric with a slurry of SiC powder and polymer precursor for SiC, followed by heat treatment for pyrolysis. The effects of heat treatment parameters o n the crystallization of the polymer-derived SiC, the composite microstruct ure, and the transverse thermal properties were assessed. Whereas composite s heat-treated at 1000 degreesC were crack-free and nearly fully dense, com posites that were subjected to further multiple reinfiltration and heat tre atment cycles at 1600 degreesC developed porosity and cracking. However, th e transverse thermal conductivity was increased significantly by the higher -temperature heat treatment, to values higher than that or a composite with a chemical-vapor-infiltration SiC matrix and the same fiber reinforcement.