Wear and corrosion properties of the Cr-Ta coating deposited by electrospark deposition on the CrNi3MoVA steel

A Cr-Ta coating with a thickness of approximately 30 μm was deposited on a CrNi3MoVA steel substrate using electrospark deposition, and its wear and corrosion properties were investigated. The dense Cr-Ta coating with fine grains is composed of Cr2Ta and Fe-Cr solid solution and metallurgically bonded to the substrate. Compared to the CrNi3MoVA steel, the Cr-Ta coating exhibits higher hardness, lower friction coefficient and wear loss. The main wear mechanism of the CrNi3MoVA steel is adhesive wear while that of the Cr-Ta coating belongs to abrasive wear. Furthermore, in contrast to the CrNi3MoVA steel, the Cr-Ta coating has a corrosion current density reduced by one order of magnitude, a corrosion potential shifted by approximately 0.05 V in the positive direction, and an electrochemical impedance increased by six times. These results indicated that the Cr-Ta coating significantly enhances the wear and corrosion properties of the CrNi3MoVA steel.