The effect of yttrium on cathodic arc evaporated Ti0.45Al0.55N coating

This work aims to understand the effect of 1 at.% Y addition on cathodic arc evaporated Ti0.45Al0.55N coating. Ti0.45Al0.55N coating and Ti0.45Al0.54Y0.01N coating were deposited on WC-Co substrate by cathodic arc evaporation method, and their microstructure and properties were compared. The addition of 1 at.% Y does not change the crystalline phase of Ti0.45Al0.55N coating. It still consists of (Ti,Al)N phase with a cubic NaCl-type structure. However, addition of Y leads to reduction of columnar structure and refinement of grains. Compared with Ti0.45Al0.55N coating, the hardness of Ti0.45Al0.54Y0.01N increases by 24%. The residual stress of Ti0.45Al0.54Y0.01N coating is approximately three times that of Ti0.45Al0.55N coating. Ti0.45Al0.54Y0.01N coating exhibits superior oxidation resistance, owing to the retardation of oxide layer growth, the dense fine-grained structure and the improved oxide layer adhesion.