Oxidation Resistance of TiAlN Coatings Deposited by Dual High-Power Impulse Magnetron Sputtering

Ti 1 – x Al x N coatings with different Al content ( x = 0.1–0.43) are grown on WC–Co substrates by dual high-power impulse magnetron sputtering in the Ar/N 2 atmosphere. The coating resistance to high-temperature oxidation is determined. For this, the phase composition change is investigated by synchrotron radiation during heating in the air from room temperature to 1100°С. Mechanical properties (hardness, elastic modulus, plasticity index, and plastic deformation resistance) are determined by nanoindentation of coatings before and after heating to 1100°С. X-ray diffraction patterns demonstrate the formation of the TiO 2 phase on the surface of all coatings, while the formation temperature and the phase type (brookite or rutile) depend on the Al content in the coating. All coatings are not subject to spinodal decomposition into the TiN and AlN phases after heating to 1100°С. The Ti 0.57 Al 0.43 N coating possesses the highest heat resistance; it undergoes the smallest change in the phase composition and mechanical properties after the high-temperature treatment.