Corrosion resistance, wear resistance and tribocorrosion of Ni–Mo–B electrodeposited coatings

Corrosion-resistant electrodeposited Ni–Mo–B coatings of various chemical compositions were obtained from a self-regulating electrolyte, and their micromechanical, tribological, and tribocorrosion properties were investigated. The influence of electrodeposition parameters on the composition, structure, and characteristics of Ni–Mo–B coatings was studied. They exhibit a fine-grained structure with 8–27 wt% Mo and 1.3–3.39 wt% B, free of pores and cracks. It was established that an increase in molybdenum content enhances the corrosion resistance of the coatings in chloride-containing media. The micromechanical properties of coatings with 8 and 16 wt% Mo were examined using scratch testing and dynamic nanoindentation, while their tribological and tribocorrosion characteristics were evaluated under a “plane–ball” configuration in air and in 3% NaCl solution, respectively. It was revealed that coatings with 8 wt% Mo perform better under dry friction conditions, whereas coatings with 16 wt% Mo are more effective under tribocorrosion loading. Ni–Mo–B coatings can serve as an environmentally friendly alternative to hard chromium.