Effect of Thermal Exposure Temperature and Time on Friction and Wear Properties of TiAlSiN Gradient Coatings

TiAlSiN gradient coatings were applied onto a cemented carbide steel substrate using cathodic arc ion plating technology. High-temperature oxidation experiments were conducted on the coatings in a box-type Maffei furnace to investigate the impact of thermal exposure temperature and duration on the surface morphology and wear characteristics of the TiAlSiN gradient coatings. The study revealed that the surface flatness of the coating remained stable after exposure to temperatures between 600 and 800°C for 1 h, with no oxides detected in the physical phase analysis. However, at 900°C, the surface flatness deteriorated, and TiO, TiO₂, and Al₂O₃ oxides were identified. Subsequent tests at 800°C for 0.5, 1, and 2 h showed that the coating maintained good surface flatness, dominated by AlN and TiN phases, with no oxide formation. Specifically, at 800°C for 1 h, the coating exhibited reduced surface roughness and wear volume compared to 900°C for the same duration, by 0.03% and 39% respectively. After 2 h at 800°C, the wear volume was 2.13 times that of 1 h at the same temperature. Overall, the TiAlSiN gradient coatings demonstrated excellent wear resistance and thermal stability at high temperatures of 600°C and 700°C, as well as at 800°C for 0.5 and 1 h.