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

Ni–Al 2 O 3 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 Al 2 O 3 nanoparticles in electrolyte were studied about the effect on the surface morphology and co-deposition of Al 2 O 3 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 Al 2 O 3 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 Al 2 O 3 addition (30 g/L), the co-deposition of Al 2 O 3 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.