Study On Preparation And Perrormance Of Ni-Mn-Graphene Composite Coating

In this paper, the Ni-Mn-graphene composite coating was prepared by the electrodeposition technique. The influences of different concentration of graphene oxide, current density and temperature were studied in the composites. The organizational structure, surface morphology and elementary composition of the Ni-Mn-graphene composite coating were investigated by using X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The Tafel curves and electrochemical impedance spectroscopy of the Ni-Mn-graphene composite coating was analyzed in 3.5 wt% Na Cl solution.The results of direct current electrodeposition indicate that concentration of graphene oxide is 1.2g/L, current density is 3.93A·dm-2, temperature is 323.15 K. The micorstructure of Ni-Mn-graphene composite coating indicates that the crystal particles is uniform and dense, the organization structure is Ni(111), and the content of carbon is the largest in the Ni-Mn-graphene composite coating. Meanwhile, the thickness and hardness is the largest. The corrosion resistance of Ni-Mn-graphene composite coating is best.The results of pulse electrodesition indicate that pulse rate is 30%, the deposition rate of Ni-Mn-graphene composite coating is the fastest, The micorstructure of Ni-Mn-graphene composite coating indicates that the surface is little hole and flat, grain size of the coating is small and the surface is more uniform and dense. Also the diffraction peak is the most intense. thickness and hardness of Ni-Mn-graphene composite coating is the largest. The corrosion resistance is best.Ni-Mn-graphene composite coating was heated under different temperature. The influences of temperature on coating microstructure, microhardness and corrosion resistance after heat treatment was studied. The results indicate that different heat treatment temperature have no effect on crystalline phase transition, but helpful to the growth of crystals. when the heat temperature is 573.15 K, the corrosion resistance of Ni-Mn-graphene composite coating is best. Temperature is more than 573.15 K that damaged the coating.