Effects of Mo addition on tribological performance of plasma-sprayed Ti-Si-C coatings

摘要

Ti-Si-C-Mo composite coatings were fabricated by plasma spraying using Ti, Si, graphite and Mo powders. The effect of Mo on microstructure and tribological performance of the Ti-Si-C coatings were investigated. The results showed that the Ti-Si-C coating consisted of TiC, Ti3SiC2, Ti,Si s, and residual graphite. The Ti-Si-C Mo coatings consisted of TiC, Ti3SiC2, Ti5Si3, residual graphite, Mo and Mo5Si3 phases. With increasing Mo contents, the fractions of Mo and Mo5Si3 phases increased, and the fractions of Ti3SiC2 and Ti5Si3 phases decreased. All the coatings existed a typical lamellar structure. The addition of Mo enhanced the hardness and fracture toughness of Ti-Si-C coating by 16% and 52%, respectively. The coating porosity decreased by 57.6%. The wear resistance of the Ti-Si-C coating was also improved and the mass loss decreased by 83%. The wear mechanism of the Ti-Si-C-Mo coatings was the combination of abrasive wear, adhesive wear, and tribo-oxidation wear.