Oxidation resistance of SiC nanowires reinforced SiC coating prepared by a CVD process on SiC‐coated C/C composites

Abstract Oxidation protective SiC nanowires‐reinforced SiC (Si CNW s‐SiC) coating was prepared on pack cementation ( PC ) SiC‐coated carbon/carbon (C/C) composites by a simple chemical vapor deposition ( CVD ) process. This double‐layer Si CNW s‐SiC/ PC SiC‐coating system on C/C composites not only has the advantages of SiC buffer layer but also has the toughening effects of Si CNW s. The microstructure and phase composition of the nanowires and the coatings were examined by SEM , TEM , and XRD . The single‐crystalline β‐SiC nanowires with twins and stacking faults were deposited uniformly and oriented randomly with diameter of 50‐200 nm and length ranging from several to tens micrometers. The dense Si CNW s‐SiC coating with some closed pores was obtained by SiC nanocrystals stacked tightly with each other on the surface of Si CNW s. After introducing Si CNW s in the coating system, the oxidation resistance is effectively improved. The oxidation test results showed that the weight loss of the Si CNW s‐SiC/ PC SiC‐coated samples was 4.91% and 1.61% after oxidation at 1073 K for 8 hours and at 1473 K for 276 hours, respectively. No matter oxidation at which temperature, the Si CNW s‐SiC/ PC SiC‐coating system has better anti‐oxidation property than the single‐layer PC SiC coating or the double‐layer CVD SiC/ PC SiC coating without Si CNW s.