Study on the corrosion electrochemistry behavior and wear resistance of the arc thermal sprayed Zn–Al alloy coating

The mechanisms of deposition and solidification processes of molten droplets after collision with the substrate during arc spraying were investigated by Fluent simulation. Subsequently, the Al, ZnAl alloys and Zn–Al pseudo-alloy coatings were prepared by arc spraying through parameter optimization. Furthermore, the electrochemical properties of arc-sprayed Al, ZnAl alloys and Zn–Al pseudo-alloy coatings corroded in 3.5 wt% NaCl solution for different days were studied. The electrochemical impedance spectra (EIS) investigation indicated that the pitting corrosion occurred on the surface of Al coating, and even the substrate material also appeared to be corroded. In comparison, the Zn–Al pseudo-alloy coating has both pure Zn and Al coatings in a corrosive environment with the cathodic effect of sacrificial anode protection and the shielding effect of a passivated protective film. As a result, it has an excellent corrosion resistance. Meanwhile, the corrosion mechanism of arc-sprayed Al, ZnAl alloys and Zn–Al pseudo-alloy coatings was further characterized by the combination of SEM surface morphology and XRD pattern after the corrosion. Furthermore, the wear resistance of the above-mentioned coatings was examined, and the investigations showed that the arc-sprayed Zn–Al pseudo-alloy coatings also have an excellent wear resistance.