A crack-free SiC nanowire-toughened Si-Mo-W-C coating prepared on graphite materials for enhancing the oxidation resistance

To protect the graphite materials against oxidation at high-temperature, a SiC nanowire-toughened Si-Mo-W-C coating was prepared through a two-step technique. First, a porous structure of SiC nanowires was synthesized by a simplified chemical vapor deposition. Afterward, the treated specimen was coated with Si-Mo-W-C ceramics by the pack cementation. The microstructure, phase composition and oxidation resistance of the coating were analyzed in detail. It was found that a dense and crack-free nanowire-toughened Si-Mo-W-C coating was formed. The coating toughened with SiC nanowires could protect graphite at 1500 °C for 30 h with weight loss of 1.43%. After oxidation, there is still no any crack in the coating. It was inferred that the multiphase composition of the coating along with the toughening effects of the SiC nanowires can lead to a crack-free coating together, and then a good anti-oxidation performance was obtained.