Abstract:To improve the surface hardness, wear resistance, and corrosion resistance of AZ91D magnesium alloy, a Ni-TiN-GO (graphene oxide) composite electrodeposition layer was prepared on the surface of AZ91D magnesium alloy using nano-composite electrodeposition technology. The Ni-TiN-GO composite electrodeposition layer was then subjected to vacuum annealing. The effects of GO addition amount, vacuum annealing temperature, and holding time on the microstructure and properties of the deposited layer were investigated. Results show that when the addition amount of GO is 0.1 g/L, the deposition rate of Ni2+ is increased, and the deposited layer exhibits a uniform and dense microstructure. The Ni grains in the deposited layer show a (111) and (200) preferred orientation. The hardness of the deposited layer is increased by 10.79 times compared to that of the substrate. The friction coefficient is 0.6, and the wear mechanism is mainly adhesive wear with slight abrasive wear. The self-corrosion current density of the deposited layer is decreased by 3 orders of magnitude compared to that of the substrate. When the vacuum annealing heating temperature is 350 ℃ and the holding time is 1 h, the surface of the deposited layer is uniform and dense, exhibiting the best performance. The hardness is increased by 1.15 times compared with that without annealing. The friction coefficient is reduced to 0.4, the wear mode is converted to weak abrasive wear. The self-corrosion current density is reduced by 2.34 times, and the resistance to Pseudomonas aeruginosa microbiologically influenced corrosion is improved. This study will lay the foundation for promoting the widespread application of AZ91D magnesium alloy in the field of equipment light massing and under complex working conditions.