Tribological performance of thermal sprayed coatings under abrasive conditions

Abstract

In this work, the tribological behaviour of thermally sprayed titanium and chromium ceramic-based coatings was investigated under abrasive conditions. Their structure was studied by a scanning electron microscope (SEM), while their hardness was evaluated using a microhardness tester. To study the strength of these ceramic coatings under abrasion conditions, reciprocating sliding experiments were carried out in a high-precision (10 mN resolution, 1000 Hz data acquisition) pin-on-disk apparatus and by using a Ø6 mm corundum ball to generate high contact pressures (1.5 GPa). To thoroughly investigate the friction evolution of the tribo-system, three-dimensional mapping of the tangential friction forces (triboscopy) was performed. Following the abrasion experiments, the wear of these coatings was measured using confocal microscopy. The obtained friction and wear results were compared to state-of-the-art materials and coatings that are currently being used in various industrial applications. From this comparison, it was found that the titanium and chromium ceramic-based coatings have comparable if not better tribological properties for the given conditions. The main wear mechanism was mainly two-body abrasion due to the surface roughness of the counter-material, as well as three-body abrasion due to the formation of debris at the interface.