Microstructure and Properties of Electro-brush Plating Ni-graphene Composite Coating

Ni-graphene composite coating was prepared on 45 steel substrates by electro-brush plating. The graphene layers,graphene in the composite coatings,the grain size and morphology of the coatings were characterized by transmission electron microscope(TEM),atomic force microscope(AFM),scanning electron microscope(SEM),energy dispersive spectrometer(EDS),Raman spectrometer,X-ray diffraction(XRD). The hardness of coatings was investigated by microhardness tester. The results show that graphene in Ni-graphene composite coating exists in the form of three(type Ⅰ,type Ⅱ,type Ⅲ),compared with the pure Ni coating,the grain size of Ni-graphene composite coatings reduces; when the content of graphene is 0.5g/L,the quality of Ni-graphene composite coating is best; because of the high hardness of graphene and its fine-grain strengthening effect,the hardness of Ni-graphene composite coating is 15.2% higher than that of pure Ni coating.