Temperature-dependent oxidation behavior of arc evaporated Al–Ti–B–N coatings

Arc evaporated Al–Ti–B–N coatings were investigated concerning the oxidation behavior. The addition of B promotes the formation of an amorphous scale with mixed oxides of Al, Ti, and B, thus resulting in a higher oxidation rate than the Al–Ti–N coating at 800 °C. At higher temperatures (≥900 °C), B-containing coatings exhibit a better oxidation resistance. The oxidation at the interface between the oxide and nitride led to the continuous formation of the amorphous inner layer with excellent adhesion. Simultaneously, the crystalline outer oxide layer at elevated temperatures inhibited the inward diffusion of oxygen. • The oxidation process of arc evaporated Al–Ti–B–N coatings was elucidated. • B-addition promotes the growth of an amorphous oxide scale during oxidation. • The crystalline outer and amorphous inner layers decrease the oxidation rate. • Al–Ti–B–N coatings show a better oxidation resistance than Al–Ti–N at 900 °C.