Improving the Properties of Ni-ZrO2 Composite Coatings by Sol-Enhanced Electroplating

ZrO2 powder has been used as a second phase in metal coatings which can significantly improve the wear resistance of composite coatings. By using newly developed sol-enhanced electroplating method, Ni-ZrO2 composite coating has been deposited on mild steel samples. The microstructure, hardness and wear property of sol-enhanced electroplated a Ni-ZrO2 composite coatings with different ZrO2 sol concentration were analyzed using SEM, XRD, micro-hardness and wear tests. The effect of ZrO2 sol concentration on the surface morphology, microstructure and mechanical property of electroplated coatings was discussed and compared with Ni-ZrO2 composite coatings prepared by adding ZrO2 powder. It was found that incorporation of ZrO2 sol improves the mechanical property of Ni coatings in composite coatings. Compared with the traditional ZrO2 powder method, Sol-enhanced method has better enhancement effect. The mechanical properties of Ni-ZrO2 coatings reach the optimum value when the ZrO2 sol concentration is 15 ml/L.