Material Design And Properties Investigation Of Ni Plating Coating On The Surface Of Low Carbon Steel

Low carbon steels are widely applied in many fields because of their excellent strength; ductibility and economy. However the poor anticorrosion and moderate wearability of low carbon steels limit their applications in some fields. Low carbon steels coated by other plating metals can extend theirs applications. For example, the steel strip with electro-deposited nickel coating is a good material used in high-quality cell shell.Ni plating coating with mutual process and excellent comprehensive properties can efficiently enhance anticorrosion and wearability of low carbon steel. Usually, the thickness of electro-deposited coating is very thin, however the thinness coating easily leads to the exposure of substrate surface in the molding process. Peeling between the coating and the substrate caused by inappropriate heat-treatment will result in protection loss of the coating, or too high exposure of substrate element, which will reduce the anticorrosion of the coating.In this paper, Ni(NH₂SO₃)₂ is chose to be plating liquid. In order to avoid the exposure of substrate, the thick Ni coating is deposited on the surface of low carbon steel. From the thermodynamic viewpoint, on the basis of phase diagram principle appropriate heat-treatment process is used to form a single phase between the coating and the substrate, to increase interface adhesion, and to get rid of residual stress from the increasing of the coating thickness and heat-treatment. From the kinetic viewpoint, the concentration distribution in the neighborhood of interface after heat-treatment was measured. A software was programmed to resolve the inter-diffusion coefficient based on Matlab mathematic software combined with Boltzman-Matona Method. Potentiodynamic polarization curve was employed to analyze the anticorrosion of coating under various heat-treatment process. Adjusting the heat-treatment process is used to meat the needs between excellent interface adhesion, mechanical properties and the control of concentration distribution mechanical and low rate of substrate exposure.In order to reduce rate of Fe exposure and enhance anticorrosion, from the kinetic viewpoint, the thin Cr, Sn, Zn and Mo barrier layers were added between the Ni coating and the substrate respectively. The results show that adding of barrier lays not only meet the thermodynamic needs, but also inhibit Fe diffusion to the surface of the coating and enhance anticorrosion and other mechanical properties.In this paper, the innovation points concentrate on the deposition of the thick coating, the single phase was abtained from appropriate heat-treatment, and the barrier layer can enhance the anti-corrosion property.