The microstructure and mechanical properties of Ni-Co-ZrO2 nanocomposite coatings

Ni-Co-ZrO2 nanocomposite coatings have been electroplated on mild steel by adding ZrO2 nanoparticles into an Ni-Co plating solution. The microstructure and mechanical properties of nanocomposite coatings were systematically investigated. The results show that the microhardness of Ni-Co-ZrO2 nanocomposite coatings varied significantly with the quantity of ZrO2 nanoparticles. Ni-Co-10 g/L ZrO2 nanocomposite coating exhibited the optimum mechanical properties due to the dispersion strengthening effect. Addition of ZrO2 nanoparticles beyond 10 g/L led to particle agglomeration and caused a porous coating structure, resulting in a deterioration of coating mechanical properties.