Fabrication and properties evaluation of functionally graded Ni-NCZ composite coating

Functionally graded Ni-ZrO2 (FGN-Z) and functionally graded Ni-NCZ (FGN-NCZ) composite coatings have been successfully co-electrodeposited from a bath containing variable concentrations of the particles. NCZ (electroless‑nickel coated ZrO2) particles were manufactured by dispersing of ZrO2 powder in an electroless-Ni plating bath. To produce functionally gradient composite coatings, ZrO2 and NCZ concentrations were continuously increased in the electroplating bath. With increasing of co-electrodeposited ZrO2 and NCZ particles content in Ni matrix, microhardness increases from interface towards the surface of the coating. The results showed that FGN-NCZ has higher wear resistance and corrosion resistance compared to FGN-Z. These were attributed to the higher amounts of co-electrodeposited second phase particles, stronger bonds between matrix and second phase particles and larger amounts of microhardness achieved for FGN-NCZ with respect to FGN-Z.