The friction and wear characteristics of cathodic arc ion-plated (V, Ti)N coatings in sliding against alumina ball

The friction and wear characteristics of cathodic arc ion-plated (V, Ti)N coatings have been studied by using a SRV wear tester with reciprocating motion in sliding against alumina ball. The as-deposited (V, Ti)N coating consists of V-rich and Ti-rich nitrides with distinct differences in lattice parameter of cubic phase. The (V, Ti)N coating exhibits a friction coefficient of 0.68–1.08 at room temperature, depending on load and frequency. The worn surfaces and wear debris are investigated to identify chemical composition and phase structures generated during the wear test. The wear process of (V, Ti)N coatings against alumina ball in air is dominated by the tribo-oxidational reaction. At low load and frequency, the wear debris consists of (V, Ti)N flakes and (V, Ti, Al)2(O, N)5-type nano-scale particles. At high load or frequency, as more alumina is removed from the coupled ball, nano-scale oxidized products of (V, Ti, Al)2O5, Al2O3 particles and a mixed (V, Ti)N·Al2O3 transfer layer are generated during wear process.