Microstructure, Wear Resistance and Corrosion Resistance of ZnNiAl Coating Prepared by Arc Spraying Dissimilar Wires

ZnNiAl coating was obtained on the surface of Q235 steel substrate by double-guns arc spraying Ni95Al5 wire and Zn85Al15 wire simultaneously. The phase, surface morphology and composition of the coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The wear resistance and corrosion resistance of the coating were studied through hardness testing, friction and wear testing, and electrochemical testing. The results show that the ZnNiAl coating had a multiphase structure which was composed of Zn phase, Ni (Al) solid solution phase and Al phase, with a small amount of oxide particles and micropores. The wear morphology of the coating exhibited a composite feature of adhesive wear and abrasive wear. The passivation effect of elements zinc and aluminum in the coating, as well as the addition of nickel, could reduce the corrosion rate of the coating, achieving the improvement of wear resistance and corrosion resistance.