Effect of bias voltage on microstructure, mechanical and tribological properties of TiAlN coatings

TiAlN multilayer coatings composed of TiAl and TiAlN layers were deposited on ZL109 alloys using filtered cathodic vacuum arc (FCVA) technology. The effect of bias voltage on the microstructure and properties of the coating was systematically studied. The results show that the coating exhibits a multi-phase structure dominated by TiAlN phase. As the bias voltage increases, the orientation of TiAlN changes from (200) plane to (111) plane due to the increase of atomic mobility and lattice distortion. The hardness, elastic modulus and adhesion of the coating show the same trend of change, that is, first increase and then decrease. When the bias voltage is 75 V, the coating exhibits the highest hardness (~30.3 GPa), elastic modulus (~229.1 GPa), adhesion (HF 2) and the lowest wear rate (~4.44×10⁻⁵ mm³/(N·m)). Compared with bare ZL109 alloy, the mechanical and tribological properties of TiAlN coated alloy surface can effectively be improved.