Improvement of Microstructure and Wear Resistance of the Ni-La2O3 Nanocomposite Coatings by Jet-Electrodeposition

A jet electrodeposition, a special electrodeposition method, was used to produce Ni-La2O3 nanocomposite coating. The influence of key experimental conditions including current density and La2O3 nanoparticles added in the electrolyte on the composite coating morphology, phase structure, surface roughness, microhardness and wear resistance were examined. It is found that by properly increasing the La2O3 nanoparticles in the electrolyte and increasing the current density, a composite coating with dense and grain-refined structure can be formed with improved surface roughness and mechanical and tribological properties. It is also proved that jet velocity helps to increase the La2O3 content in the composite coating. With the optimal experimental parameters including a current density of 80 A/dm2, La2O3 addition of 30 g/L and jet velocity of 8 m/s, a smooth and consolidated Ni-La2O3 coating was obtained with a hardness of 618 HV, surface roughness of 0.213 μm and wear rate of 6 mg/min. A smooth and only slight abrasive wear of the worn surface was also observed.