CrN–TiN multilayer coating on magnesium alloy AZ91 by arc-glow plasma depositing process

CrN–TiN multilayer films were deposited on magnesium alloy AZ91 by a novel method of arc-glow plasma depositing to improve its wear resistance. The total thickness of the coating was about 2 μm with 12 sub-layers of CrN and TiN deposited alternately.The composition and microstructure of the coating layer were analyzed by means of X-ray diffraction (XRD) and glow discharge spectrum (GDS). The surface and sectional morphologies were surveyed through scanning electronic microscopy (SEM). The surface micro-hardness was measured. The adhesion strength between film and substrate was surveyed by the test of stick-tearing. The performance of wear resistance was evaluated by ways of ball on disc rubbing. The corrosion behavior of the coated samples had also been evaluated through neutral salt spray test. The results indicate that CrN–TiN coating effectively improved the performance of wear resistance and corrosion resistance of AZ91.