Tribological and Corrosion Behavior of Ni–Mo Coatings Electrodeposited at Varying Current Densities
摘要
The present study involves the electrodeposition of thick Ni–Mo binary alloy coatings containing 16.1–39.6 wt pct Mo onto steel substrates from an alkaline sulfate–citrate bath using direct current. The Mo content in the coatings varied significantly from 39.6 wt pct at 20 mA/cm2 to 16.1 wt pct at 100 mA/cm2. At lower current densities, the coatings exhibited a smooth and nodular surface morphology; however, this shifted to a relatively coarse, cauliflower-like morphology with increasing current density. The nanocrystalline single-phase solid solution coatings produced via electrodeposition notably improved both the mechanical and corrosion resistance of the plain carbon steel substrate. In particular, the coating deposited at 60 mA/cm2 showed outstanding performance, with a microhardness of 618 Hv, a minimal wear volume loss of 0.05 mm3, and a low corrosion current density of 1.2 μA/cm2.