Wear behaviour of nanostructured alumina–titania coatings deposited by atmospheric plasma spray

Dry sliding wear performance of Al2O3–13% TiO2 nanostructured and conventional coatings has been experimentally analysed. An enhanced behaviour of the nanostructured material can be reported with substantially minor wear rates under all experimental conditions. Additionally, a transition from mild to severe wear can be established in both materials. However, the critical pressure at which the transition occurs is higher for the nanocoating. The main wear mechanisms controlling the mild and the severe regimes are related to brittle propagation of cracks. The hierarchical structure showed by the nanomaterial seems to control the improvements mentioned before. Crack deflection processes leading to a toughening effect can be identified, although, the microstructural feature which deflects the cracks changes depending on the wear regime.