Influence of Si Addition on the Chemical and Tribological Performance of TiAlCrN Coating Deposited by Co-Sputtering

Abstract

In this work, nanostructured TiAlCrN coatings were deposited on a WC-Co substrate using a co-sputtering process varying the silicon composition on the coatings. The influence of silicon content on the mechanical, chemical, and tribological performance of the coatings was studied. The hardness increases from 11 to 16 GPa with the Si content; also, Young’s modulus increases from 260 to 295 GPa. The H/E ratio, which is a measure of materials’ ability to take the strain before deformation, is also increased with the increase in Si content, suggesting increased toughness. XPS analysis reveals that the coatings present titanium, aluminum, chromium, and silicon nitrides. The tribological behavior of the coatings was conducted through ball-on-disc tests, in which the results show that the coefficients of friction range from 0.15 to 0.55, with the lowest for the samples with the highest Si content. This behavior is benefited by the formation of oxynitride species, identified by XPS, which acts as lubricating layers and diffusion barriers. TiAlCrSixN coating presents a potential application for severe wear owing to its tribological performance.