Tribological performance of ternary TiMN films (M=AL, B, and Cr) deposited by cathodic arc on M2 steel

Abstract

In the industry, the titanium nitride (TiN) coating is widely used in cutting tools, decorative and corrosion protection film, but unfortunately, this coating presented a poor performance under some work condition. For that, different studies have been dedicated to improving its properties with the inclusion of a third element that modifies the film structure, chemical and mechanical properties. In this work, TiN layers with/without of Al, B, and Cr inclusion were studied in order to analyze their effect in the film tribological performance. These were deposited using cathodic arc PVD technic on AISI-M2 steel. They were chemical and structural characterized using EDX and XRD, respectively. While the film thickness was determinate using a ball-cratering technique. Their tribological performance was studied using a sliding reciprocating movement in dry conditions, under three loads, at 30 min against Al₂O₃ ball as counterbody. The resulting wear tracks were studied using optical microscopy in order to study the wear mechanism. Raman spectroscopy was used to determinate the chemical changes produced on wear zones and the lost material was measured with a stylus profilometer. As result, the structure and morphology were modified with the inclusion of the third element. The TiN with the inclusion of Al and B presented a higher friction force and wear rate than TiN films. While the TiN with Cr inclusion film presented the best tribological performance with lower wear rate and friction coefficient. The Raman studies did not showed considerable changes on the damage coted surface areas, except for TiAlN coating that show the M2 tool steel Raman spectra on the areas where the film was removed.