Effect of ZrB 2 on the wear resistance and corrosion properties of nanocrystalline Ni-Cu coatings fabricated by electrodeposition

In this study, a pulsed electrodeposition approach was used to create a Ni-Cu/ZrB 2 composite coating on the surface of J55 steel. Ni-Cu/ZrB 2 composite coatings with different material additions were prepared, and the surface morphology, grain size, microhardness and wear and corrosion resistance were investigated. The results confirmed that the embedding of ZrB 2 in the Ni-Cu coating can refine the grains and make the coating surface denser. Furthermore, ZrB 2 can effectively increase the wear resistance and corrosion resistance of the coating; the Ni-Cu/ZrB 2 (1.0 g/L) composite coating reflects this by having the shallowest and narrowest wear cross-section as well as the lowest average friction coefficient (0.537). Additionally, the composite coating has the highest impedance modulus, reaching 83.60 kΩ/cm 2. The composite coating improved corrosion resistance by 63.1 % compared to the pure sample. The enhancement in the coating's corrosion resistance can be attributed to three factors. Firstly, the addition of zirconium diborate refines the coating grain and changes the corrosion type from pitting corrosion to homogeneous corrosion. Secondly, zirconium diborate forms a physical barrier against corrosive ions. Lastly, the formation of the oxide layer on the coating during the process of corrosion, also enhances the material's resistance to corrosion.