Studies Of Electroplating Fe-Ni-Cr Imitated Stainless Steel Alloy Coating

The stainless steel material and its production have been applied in different areas of manufacture industry because of its good function and beautiful appearance. However, the stainless steel is too expensive and is difficult to be molded. Fe-Ni-Cr alloy imitated stainless steel coating can be electrodeposited on the surface of material instead of the stainless steel. At the same time, Fe-Ni-Cr alloy can be widely used because of its protective and decorated function, low production cost.Fe-Ni-Cr alloy imitated stainless steel coating was comprehensively studied in the paper. The technological condition ranges of bath were confirmed elementarily, and the optimum formulation of bath composition and technological conditions was obtained to be Cr2(SO4)3·6H2O 200g/L, FeSO4·7H2O 9g/L, NiSO4·6H2O 6g/L, C6H17N3O7 60g/L, C6H8O6 10g/L, H3BO3 25g/L, (NH4)SO4 100g/L, NaF 4g/L, C12H25NaO4S 0.06g/L, Dk=16A/dm2, T=50℃, pH=1.5. Fe-Ni-Cr alloy co-electrodeposited mechanism as well as complexant and additive effect mechanism was analyzed by the cathodic polarization curve and cyclic voltammetry curve. The dispersing power, covering power and stability of bath were tested and combine intensity, scanning electron microscopy(SEM), thickness, X-ray diffraction(XRD), hardness, anticorrosion performance of Fe-Ni-Cr alloy imitated stainless steel coating were also tested. The corrosion production, corrosion process and anticorrosion mechanism were analyzed by SEM, enegy dispersive X-ray Analysis(EDX) and electrochemical impedance spectroscopy(EIS) test.Curve experiment indicated the Fe-Ni-Cr ally coating had good combine ability. The thickness test showed it was hard to be thicker with the longer time and a 20μm imitated stainless steel coating could be gained. XRD analysis showed the coating was amorphous configuration. As shown by the hardness test, the coating became harder as the Cr content increased and imitated stainless steel coating had almost the same hardness with the stainless steel sample. As indicated by the anticorrosion test, the coating had a better anticorrosion performance as the Cr content increased and imitated stainless steel coating had almost the same anticorrosion performance with the stainless steel sample. The EIS test showed corrosion process could be divided into two stages, including the inducement period and the development period of hole corrosion on the passivation film.Fe-Ni-Cr alloy imitated stainless steel coating whose composing, hardness and anticorrosion performance were almost accorded with the 304 stainless steel from above experiment.