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.