The surface magnetization approach on assessing tribological properties of steels with different TiN coatings

Abstract

The dynamic tribological properties of thin films over the past decades have been monitored using friction coefficient, and that is despite the relatively low sensitivity of the measurement in many sliding conditions. The search is therefore on improved physical measurements other than friction coefficient to monitor the film tribological characteristics in sliding contacts. This article introduces the novel technology of using surface magnetization variations for evaluating the wear-resistant properties of thin ceramic films. The experiment was conducted on pairs of SUS304 steel rubbing with SKD11 steel substrate coated with different TiN films (physical vapour deposit and chemical vapour deposit) under different normal loads under dry friction condition. By monitoring the dynamic variations of surface magnetization and friction coefficient in conjunction with SEM observations of the wear tracks, the effects of normal loads on the friction and wear properties for the die surfaces coated with different TiN films were investigated. The experimental results showed that the continuous surface magnetization variations can be used to determine the onset of film fracture and the endurance life of the ceramic film more accurately than that by friction coefficient variations. Therefore, the novel method of using surface magnetization variations does show great potential for evaluating the tribological properties of steels with different TiN films.