Wear behavior of electrodeposited nickel/graphene composite coating

The agglomeration of the doped graphene powder during electrochemical deposition and non-uniform dispersion in the nickel coating matrix are problems to be solved urgently. In order to solve these problems, a graphite flake was used for the anode, and on the basis of Watt's type electroplating solution, sulfuric acid was introduced to strip the graphite. Since the electroplating solution can peel graphene, the anodic peeling and cathodic deposition of graphene can be realized simultaneously, and the nickel/graphene composite coating can be obtained. The results showed that the exfoliated graphene (EG) was uniformly dispersed in the coating without agglomeration, which exhibited a typical wrinkled double-layer structure. The addition of graphene changed the preferred orientation of nickel from (200) to (111), the crystal grains were refined, and the performance was significantly improved. The microhardness of the nickel coating was increased from 186 HV to 330 HV, the friction coefficient was reduced to 0.16, and the wear rate was only 3.2 × 10−5 mm3 (N·m)−1. This research provides a new idea to solve the problem of graphene agglomeration and uniform dispersion in the electrolyte and coating and offers a new solution for the efficient preparation of nickel/graphene composite coatings with uniform graphene dispersion. [Display omitted] •Graphene synthesized by graphite anode during the electrochemical deposition process•The obtained graphene with the nickel ions in the cathode co-formed the coating•Dispersing uniformly of graphene in the coating•Settling agglomeration of graphene to improve wear resistance of the coating.