Bamboo-shaped SiC nanowire-toughened SiC coating for oxidation protection of C/C composites

An oxidation protective bamboo-shaped SiC nanowire-toughened SiC coating was prepared on the carbon/carbon composites by chemical vapor deposition and pack cementation. It is found that incorporating bamboo-shaped SiC nanowires makes the coating hardness and elastic modulus increase by 20.07% and 40.42% and microcrack density decrease by 84.04% due to their unusual toughening mechanism resulting from the nanoscale mechanical interlocking between the nodes and the surrounding matrix, resulting in a good oxidation inhibition for the coated samples. The result showed that the weight loss of the coated samples was only 0.5% after isothermal oxidation at 1500 °C for 72 h.

► Bamboo-shaped SiC nanowire-toughened SiC oxidation protective coating was prepared. ► An unusual toughening mechanism of the nanoscale mechanical interlocking was found. ► The coating had a good oxidation protective ability for C/C composites at 1500 °C. ► The oxidation of C/C mainly occurred in the variable-temperature stage.