Fretting wear behaviors of APS AT40 coating and Al2O3/AT40 composite coating on TC6 alloy

Abstract To improve the fretting wear resistance of TC6 alloy, AT40 coating and Al2O3/AT40 composite coating were prepared on TC6 respectively by atmospheric plasma spraying (APS) technology. The microstructure, composition and adhesion strength of the two coatings were studied, and the fretting wear behavior of TC6 substrate and the coatings were investigated. The results showed that, the two coatings were of lamellar stacked structures with holes and micro-cracks in stacked areas, and combined well with substrate. AT40 coating was composed of the Al2TiO5, Ti3O5 and α-Al2O3, and Al2O3/AT40 composite coating was formed by inner transition AT40 layer and outer Al2O3 layer. The inner transition AT40 layer had good compatibility with TC6 titanium alloy and Al2O3 layer, and the outer Al2O3 layer consisted of α-Al2O3 and γ-Al2O3. The two coatings significantly improved the fretting wear resistance of TC6 alloy, and the fretting wear mechanism of the two coatings was fatigue wear and slight adhesive wear.