Carbon/carbon composites (C / C) have been widely studied in the aerospace field given their excellent thermal shock resistance and specific strength at high temperatures. However, they are associated with the problem of rapid oxidization and deterioration under normal atmospheric environments. In order to overcome these problems, chemical vapor deposition (CVD) coatings of ultra-high temperature ceramics to C / C have become an important technical step. In this study, TaC coatings on C / C were carried out by a CFD simulation and a subsequent CVD process. A TaC monolayer and a SiC / TaC / SiC / TaC multilayer were compared with respect to the degree of thermal shock resistance, accomplished in this case with an arc heater. The TaC monolayer was mostly delaminated on the horizontally oriented carbon fibers, which resulted in sharpened carbon fibers and porous Ta₂O₅ layers. However, the multilayer structure showed a protective vitreous coating due to the oxidation of the SiC layer, with the inner C / C successfully protected by the porous Ta₂O₅ layer underneath. It can be concluded that multilayer coatings of SiC / TaC / SiC / TaC can be more effective for thermal shock and oxidation resistance capabilities of composites.

Keywords: Ultra high temperature ceramics, Chemical vapor deposition, Tantalum carbide, Thermal shock resistance