Tribological Behavior of Magnesium Alloy AZ91 Coated with TiN/CrN by Arc-glow Plasma Depositing

With advantages of high specific strength, low elastic module, good damping property et al., the magnesium alloys exhibit great potential applications in aerospace. But poor wear behavior results in limited use of magnesium alloy to static components. In this study, a 2 μm thick coating with 12 sub-layers of CrN and TiN is deposited alternately on the surface of magnesium alloy AZ91 by a novel method of arc-glow plasma depositing to improve its wear resistance. The composition and microstructure of the coating layer are analyzed by means of SEM, XRD and GDS. The friction coefficient is measured by ball on disc rubbing test, and the wear rates are also calculated. The results indicate that the friction coefficient is increased, but the wear rate is dropped sharply as compared with bare metal. The surface hardness is about HK0.01 1400.