To investigate the effect of W content on the tribological properties of Ni-W alloy coatings,Ni-W alloy coatings were prepared on the surface of 45 steel substrate using pulse electro-deposition technique.The influence of tungsten content on the microstructure,mechanical,and tribological properties of the Ni-W alloy coatings was investigated.The results show that the grain size of the Ni-W alloy coatings is uniform and dense,and the bond between the coating and the substrate is tight.Compared with the 45 steel substrate,the Ni-W alloy coatings have higher hardness,and the hardness increases with the increase of tungsten content.The wear behavior of the 45 steel substrate is mainly abrasive wear,while the Ni-W coating is mainly adhesive wear and abrasive wear,and with the increase of W content,the wear resistance of the coatings gradually improves.Under dry friction and PAO6 oil lubrication conditions,Ni-W alloy coating can significantly reduce the wear of the material,especially under oil lubrication conditions,there is almost no wear on the coating surface.Therefore,the pulse electro-deposited Ni-W alloy coatings demonstrate excellent tribological performance,and the mechanical and tribological properties can be effectively improved by adjusting the tungsten content in the coatings.