Microstructure, mechanical and friction-wear properties of SiC-WC composite with Al and C as sintering aids

Low strength and poor performance of SiC–WC composite for seals, attributable to the use of a large amount of liquid phase sintering additives, limit the application prospects of these materials. This study focuses on preparing high-strength, high-toughness, and wear-resistant SiC–WC composite using a small amount of aluminum and carbon black as sintering additives. The results revealed that the specimen containing 50 wt% WC exhibited the maximum flexural strength and fracture toughness of 645.9 MPa and 7.49 Mpa m 1/2 , respectively. These improvements were attributed to the deoxidizing and solid-solution effects of Al and the reinforcing effect of the WC second phase. Moreover, the specific wear rate was measured at 8.06 × 10 −7 mm 3 N −1 m −1 , which was 56.9 % lower than that of monolithic SiC. Results from Raman spectral analysis provided evidence of the presence of W–O bonds on the wear surface, indicating that the SiO 2 film could be successfully replaced by a WO 3 film.