Improvement of microstructure and properties of Ni-Al2O3 composite coating via jet electrodeposition

Ni-Al2O3 composite coatings were prepared with a modified Watt's bath by using jet electrodeposition method. As the key process parameter, current density and the addition of Al2O3 nanoparticles in electrolyte were studied about the effect on the surface morphology and co-deposition of Al2O3 nanoparticles of composite coating. The mechanical and tribological properties of the composite coating were also tested. The results show that properly increasing the current density and Al2O3 addition can increase the co-deposition of nanoparticles in the coating and promote the formation of a dense and refined coating structure. Using the optimized process parameters of current density (300 A/dm(2)) and Al2O3 addition (30 g/L), the co-deposition of Al2O3 in the composite coating can reach a maximum of 13.1 at.%. The hardness of the coating reaches the peak at 623 HV. The wear rate of the composite coating is also greatly reduced with optimized parameters.