SiC coating toughened by HfC nanowires to protect C/C composites against oxidation

To prevent carbon/carbon (C/C) composites from oxidation at high temperature, a dense SiC coating toughened by HfC nanowires was prepared by a two-step technique of chemical vapor deposition (CVD) and pack cementation. The microstructure, mechanical properties and oxidation resistance of the coating were investigated. The HfC nanowires can effectively reduce the size of microcracks and avoid the formation of through-thickness microcracks in the SiC coating. Due to the toughening mechanisms including microcrack bridging by nanowire and nanowire pullout, the mechanical properties and oxidation resistance of the coating are improved.