ZrB2-reinforced electroless Ni-W-P composite coating with enhanced corrosion and wear resistance in 3.5 wt% NaCl solution

In this paper, various concentrations ZrB2 nanoparticles were applied in the Ni-W-P bath system, and a series of Ni-W-P composite coatings were fabricated via composite chemical deposition. The phase composition, microstructure, elemental distribution, and chemical states of the different coatings were systematically characterized using XRD, SEM, EDS, and XPS, and the results of the tests indicated that Ni-W-P/ZrB2 composite coatings were prepared successfully. The corrosion resistance, wear resistance and hardness of the coatings were investigated through electrochemical corrosion tests, friction tests and hardness tests. Electrochemical tests revealed that the incorporation of ZrB2 particles significantly refines the coating’s microstructure. This structural optimization directly contributes to a remarkable enhancement in corrosion resistance and mechanical properties, as evidenced by detailed analysis of the electrochemical parameters. When ZrB2 content reaches 1.25 g/L, Ni-W-P/ZrB2 composite coatings exhibited the most excellent corrosion resistance (the lowest corrosion rate of 0.00499 mm/a). To further compare the mechanical properties between the pure alloy deposit and ZrB2 strengthened composite deposit, the results of friction tests and hardness tests demonstrated that Ni-W-P/ZrB2 composite deposit has better wear resistance.