Study On Sn-Ni Mixed Salt Coloring Membrane Of High Silicon Aluminum Alloy And Its Performance

Pure aluminum doped silicon to improves its casting properties, increases its hardness and strength, but reduces the wear resistance and corrosion resistance. Studying the electrolytic coloring technology of high silicon aluminum alloy, achieving good corrosion resistance and decorative properties, which has vital significance and pressing to promote the high silicon aluminum alloy to be used in industrial application.This paper selects electrolytic coloring technology on Sn-Ni mixed-salt solution. The article has consulted on the massive literature and the early study, determinate the formulation of coloring solution and the coloring time. Used the orthogonalization design, took the color, the uniformity, and the corrosion resistance as the evaluation index, and determined the best electrolysis coloration technological conditions. The best electrolytic coloring condition is:H2SO4(170g/L), Oxidation time(24min), Oxidation temperature(26℃), Coloring temperature(26℃) and Coloring voltage(16V). On the basis of the best electrolytic coloring condition, this paper also studies the effect of the time, the coloring temperature, the AC voltage, et. al. After coloring, we got the uniform and different color film, the best condition:Coloring time(3～7min), SnSO4(2-8g/L), Coloring temperature(20-26℃), Coloring voltage(12～20V).According to the requirements of the project, the comsumption of the aluminum is less than0.9%after surface treatment. The result showed that the percentage of weight growth is1.25%,1.43%,1.61%o after anodization, electrolysis coloration processing and sealing.Used SEM to analyze the colored film, show the surface is relatively flat, the film is fine and close and closely combining the matrix metal. The thickness of film is10μm. Used EDS, XRF, XRD to analyze the electrolysis coloration membrane ingredient. The result showed that the tin elements are deposited in the film after electrolysis.Has studied electrolytic coloring film wear-resistance. The results indicated that, back and forth cleaned the electrolytic coloring film surface with metallographic sandpaper or rubber, did not have the membrane change colors tone. The heat-resistance experiment showed that the film is not suitable for more than400℃temperature. The chemical soaking experiment and neutral salt spray test(NSS) showed that electrolytic coloring membrane has good corrosion resistance.