Enhanced wear resistance of AlTiN coatings by ultrasonic rolling substrate texturing

Abstract

The purpose of this paper is to provide a feasible approach for enhancing the anti-wear performance of the AlTiN coating-AISI 5140 steel system. Regularly arranged micro-textures were prepared on AISI 5140 steel surfaces via an ultrasonic surface rolling process. AlTiN coating was subsequently deposited on the textured substrate. The tribological behavior of the AlTiN coatings was then evaluated under dry friction and lubrication conditions at loads of 5–20 N and sliding speeds of 2–10 mm/s. Results reveal that the synergistic effect of micro-textures and AlTiN coatings have a remarkable impact on the tribological properties of the steel substrates, especially in enhancing the anti-wear properties. In addition, the tribological behavior of the coated samples is sensitive to the test parameters. Under low sliding speed (2 mm/s) and heavy load (20N), the stable friction coefficient of the AlTiN coating and wear diameter of the GCr15 steel ball sliding against it decreased to ~0.51 and ~907.1 μm after substrate texturing, which was reduced by ~10.6 % and ~15.8 %, respectively, compared with those of polished coating under dry friction conditions. Also, it exhibits anti-friction and anti-wear behavior under lubricated conditions. The possible mechanisms of the effects of ultrasonic rolling substrate texturing on the tribological behavior of the coating are explored.