Electrochemical Corrosion Performance of W-MoS2 Coatings Fabricated by Electrospark Deposition

The self-lubricating MoS2 coating is highly susceptible to degradation in marine environments due to oxidative corrosion. To expand its application in high-humidity and high-salt-fog conditions, this study mixed W with MoS2 and prepared W-MoS2 self-lubricating coatings on the surface of CrNi3MoVA steel by electrospark deposition technology. The electrochemical corrosion behaviors of these coatings, with varying W/MoS2 mass ratios, were examined using an electrochemical workstation in a 3.5 wt.% NaCl solution. The findings indicated that as the MoS2 content increased, the low-frequency impedance modulus (LIMs) of the W-MoS2 coating initially rose and then declined. At a MoS2 content of 20 wt.%, the coating exhibited the highest LIM and the greatest corrosion resistance. In comparison to the CrNi3MoVA steel substrate, the corrosion current density was reduced by 67.4%, a result attributed to the coating’s dense microstructure and improved charge transfer resistance, thereby demonstrating its optimal protective performance. These results provide a laboratory electrochemical basis for designing corrosion-resistant self-lubricating ESD coatings for steel components exposed to chloride-containing environments; however, long-term immersion, cyclic salt-spray, field-exposure, and quantitative adhesion tests are still required before direct long-term marine-service durability can be confirmed.