High temperature oxidation behavior of multicomponent TiAlSiN coatings

Recently, multicomponent TiAlSiN coatings have been developed in order to possess high hardness and good thermal stability at a temperature exceeding 800 °C. In this study, a series of TiAlSiN coatings were synthesized with different ratios of Al0.89Si0.11/(Ti + Al0.89Si0.11) cathode current by using a cathodic arc evaporation system with lateral rotating arc sources. The high temperature oxidation behavior of TiAlSiN coatings with different (Al + Si)/(Ti + Al + Si) content ratios was investigated. Higher Al0.89Si0.11/(Ti + Al0.89Si0.11) cathode current ratio facilitated higher Al and Si contents. From the thermal-gravimetric analysis, the deposited TiAlSiN coating with (Al + Si)/(Ti + Al + Si) content ratio of 0.23 showed a weight gain starting at ∼ 900 °C. The TiAlSiN with a smaller grain size and a higher (Al + Si)/(Ti + Al + Si) content ratio possessed a lower oxidation rate by forming a protective oxide layer, mainly consisted of Al2O3, which inhibited further oxygen diffusion into the coating. The TiAlSiN coating with the highest (Al + Si)/(Ti + Al + Si) content ratio possessed the highest onset temperature at 1115 °C and the lowest oxidation rate.