Analysis of oxidation behavior of laser cladding SiC-Ti based composite strengthening coating

Abstract

In this paper, the oxidation behavior and high-temperature tribological properties of laser cladding Ti-Al-Si-SiCx system coatings at 800°C in the air were studied. The results demonstrated that these coatings had Ti5Si3/Ti3Al eutectic structure before oxidation. The results of oxidation resistance suggested that the oxidation weight gain conformed to the parabolic law. An appropriate increase in SiC content is beneficial to lower the oxidation rate. The Ti5Si3 phase has excellent oxidation resistance. TiC phase forms CO2 product during the oxidation process. In addition, the diffusion rates of Ti and Al elements in the oxide layer are different. The combined effect of the two eventually leads to the gradual formation of pores in the oxide layer. The TiC-reinforced phase improves the friction coefficient of high-temperature friction, but its introduction significantly improves the high-temperature wear resistance. Additionally, the adhesion of the oxide film in the high-temperature wear process exerted a great influence on the wear mechanism. Ti-Al-Si-SiC3 exhibited the lowest wear rate of 6.73 × 10−7 mm3 N−1 m−1. The wear mechanism is primarily adhesive wear, abrasive wear, and oxidative wear.