Laser cladding Ni60-SiC/Ti3SiC2 self-lubricating composite coatings on IN718 alloy: Wear mechanisms and oxidation behaviors

To enhance the service performance of IN718 alloy under severe working conditions, the self-lubricating composite coating of Ni60-SiC/Ti₃SiC₂ was fabricated on its surface using laser cladding. By systematically analyzing the microstructure and properties of composite coatings, the wear mechanism at different temperatures and the oxidation behavior at 800 °C of coatings were discussed in depth. The results demonstrate that an increase in coatings’ microhardness by a factor of 1.9–3.1 over IN718 was achieved, benefiting from the fine-grained and solid-solution strengthening actions, and the hard phases such as C₂₃C₆, Ni₃Si, TiC distributed diffusely inside the coatings. The tribological performance of coatings was also significantly improved, in which the coating with 10 wt% Ti₃SiC₂ added had the lowest wear rates of 2.13 and 3.57 × 10⁻⁵ mm³/N·m at RT and 600 °C, respectively, which were reduced by 82.74 % and 87.43 % compared to the substrate. When the test temperature changes from RT to 600 °C, the main wear form of coatings changes from adhesive and abrasive wear to oxidative wear. With the Ti₃SiC₂ content increasing, the oxide film is gradually dense and uniform, and the oxidation resistance is significantly improved.