Bamboo like SiC Nanowires Grown in a Dual-Temperature Zone Reaction System Enhance the Oxidation and Thermal Shock Resistance of SiC Coatings

The life of high temperature coating mainly depends on its oxidation resistance and bonding strength with the substrate. SiC nws / SiC coatings were prepared by a self-made two temperature reaction system and chemical vapor deposition method. The oxidation resistance of the composite coating at 900 ℃ and 1500 ℃ and the thermal shock resistance at 1500 ℃ were studied. The fracture toughness and bonding strength of the composite coating were increased by 53.8% and 9.8 times, respectively, due to the stable mechanical linkage effect between the bamboo like SiC nanowires with special nodes and SiC. Due to the healing effect of glass phase SiO 2 , the weight loss rate of bamboo like SiC nws / SiC coating sample after oxidation at 900 ℃ for 30 h is about 5.28%, and that after isothermal oxidation at 1500 ℃ for 60 h is only 0.74%. In addition, bamboo like SiC nws can effectively alleviate the thermal expansion coefficient mismatch between SiC coating and substrate. After 25 thermal shock cycles, the final oxidation weight loss rate of composite coating is only 2.03%.