Electrodeposition of Ni–ZrO 2 composite coatings and evaluation of particle distribution and corrosion resistance

Abstract

The Ni–ZrO₂ composite coatings were prepared by conventional electrodeposition method in Watts bath containing different amounts of ZrO₂ to be codeposited. Pure Ni coating was also prepared as a comparison. The distribution and amount of the particles in the coatings were studied using an optical microscope, SEM, EDX, microhardness instrument and XRD. The results showed that with increasing ZrO₂ concentration in the bath up to 90 g L⁻¹, particle content in the coating increases. If concentration of ZrO₂ surpasses 90 g L⁻¹, ZrO₂ content in the coating decreases, and distribution of the particles in the coating becomes non-uniform. Evaluation of corrosion behaviour showed that with increasing ZrO₂ content in the coating, the corrosion potential shifted towards noble and positive values, and the corrosion resistance increased. The results revealed that the electroplated sample in the bath containing 90 g L⁻¹ ZrO₂ has the maximum particle content and the best corrosion resistance.