| On the surface of aluminum and aluminum alloy products in color processing, the blackcoating because of its unique optical function and decorative performance, have broadapplication prospects in the aerospace, optical instrument and electronics and other fields.Black ceramic coating process has been developed by micro-arc oxidation on aluminumalloy in an electrolyte system containing Na2SiO3，Na3PO4，Na2CO3，A, B and additives.Through the single factor experiment and tests optimization electrolyte and electricparameters, finally obtained optimal technology parameters of black MAO coating. Theinfluences of technology parameters on micro-arc oxidation process and performance of blackceramic coatings were investigated, such as color value, chromatic aberration, surfaceroughness and adhesion.SEM, EDS, XRD, XPS, Spectrophotometer, Auto Lab electrochemical workstation,Electrochemical polarization test and other means of measurement were used to characterizethe surface and section morphology, composition, microstructure, blackness, corrosionresistance of ceramic coating. The results were shown that the black ceramic coating hassmooth surface and uniform color. Black MAO ceramic coating is dense, no obvioushierarchical structure, a few discharge pores were found on the coating surface. The coatingmainly composed of amorphous or microcrystal oxides except of a small amount of Al2O3andW. The formation of Vanadium oxide, W and Tungsten oxide result in the black color ofceramic layer. The polarization curve shown that corrosion current density of black ceramiccoating was3.55×10-4μA/cm2, four orders of magnitude lower than that of the bared alloy(5.248μA/cm2), a more obvious color difference appeared after336h ultraviolet irradiationtest, which reveal that light aging resistance of black ceramic coating formed on1060aluminum alloys by MAO is significantly improved. |
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