| Golden yellow electrolytic coloring by anodic oxidation and porcelain anodic oxidation were tested on ZL101A Al-Si alloy by self-made DC pulse power in this paper. Golden yellow films and ceramic films were prepared on Al-Si alloy surface. The influence of different processing parameters, pre-treatment and after-treatment on golden yellow effect and porcelain effect of films were researched. The film forming mechanism of Al-Si alloy anodic oxidation films and electrolytic coloring mechanism were discussesed. Digital camera (DC), scanning electron microscopy (SEM), energy spectrum analysis (EDS), X-ray diffraction (XRD), digital cladding thickness gauge, roughness instrument, microhardness tester also friction and wear tester were used for observing and analysing the color and morphology of films and detecting the thickness, roughness, composition, physical phase, microhardness and friction coefficient of films. At the same time, the adhesion of films was tested by delimit lattice test and corrosion resistance of films was tested.Test results showed that golden yellow films thickness rised and the roughness changed little with increasing of sulphuric acid concentration and oxidation time, also ceramic films thickness rised and roughness changed little with increasing of oxidation time, K2TiO(C2O4)2concentration and oxidation voltage.SEM and EDS analysis showed that golden yellow films were very dense and smooth, moreover Ag deposited in the bottom of films during electrolytic coloring process. The pore diameter of ceramic films largened with increasing of oxidation time and oxidation voltage, and diminished with increasing of K2TiC(C2O4)2concentration. Ceramic films were very dense and smooth, moreover Ag deposited in the bottom of films during porcelain anodic oxidation process. EDS test indicated that films consisted mainly of Al and O element. XRD testing results of golden yellow films showed that there were Al phase, β-Al2O3phase, Si phase and Ag phase existed, and XRD testing results of ceramic films showed that there were Al phase, γ-Al2O3phase, Si phase, a-Ti phase and β-Ti phase existed. The micro hardness of golden yellow films and ceramic films improved grately from78HV of substrate to355HV and209HV respectively, and the friction coefficient reduced from0.7of substrate to0.35and0.25respectively. Delimit lattice test indicated that films and the matrix combined with firm, the adhesion of films was good. Corrosion resistance and weather resistance of films were good. |
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