Pulsed Electrodeposition for Preparing Nickel, Silver/Graphene Double-Layer Composite Coatings and Study on Friction Properties

Nickel, silver/graphene double-layer composite coatings were prepared by pulsed electrodeposition. The composition, structure, mechanics and tribological properties of the coatings were investigated. Research shows that the Ag grains in the composite coatings decreased with the increase of graphene content. When the amount of graphene added to the bath reached 0.8 g/L, a large number of cracks were generated in the composite coating. When the amount of graphene added to the bath is 0.4 g/L, the microhardness of the composite coating is about 144 HV, much higher than that of the Ag coating (about 89 HV). Compared with Ag coating, the addition of graphene reduces the friction coefficient and wear rate of the coating. There are a lot of furrows on the Ag coating surface, and after the addition of graphene, the multilayer graphene makes the surface of the abrasion smooth, effectively reducing the friction coefficient of the coating, and the friction coefficient is more stable during the friction process.