Research On Golden Films By Anodic Oxidation And Electrolytic Coloring Of6061Al Alloy

Golden yellow electrolytic coloring by anodic oxidation were tested on6061Alalloy by self-made DC pulse power in this paper. Golden yellow films were prepared on6061Al alloy surface. The influence of different processing parameters, pre-treatmentand after-treatment on golden yellow effect of films were researched. The film formingmechanism of6061Al alloy anodic oxidation films and electrolytic coloring mechanismwere discussed. Digital camera (DC) and RAL K7CLASSIC were used for observingand analyzing the color of films. Scanning electron microscopy (SEM), energyspectrum analysis (EDS), X-ray diffraction (XRD), digital cladding thickness gauge,micro-hardness tester and friction&wear tester were used for observing and analyzingand morphology of films and detecting the thickness, composition, physical phase,micro-hardness friction, coefficient of films and corrosion resistance.Test results showed that golden yellow films thickness increased with sulfuric acidconcentration and oxidation time. The color of films turned dark, with the increase ofoxidation time and current density, also the increase of electrolysis coloring time andsilver sulfate concentration. The optimal parameters for golden yellow films preparedwere, that：sulfuric140g/L, Al2O33g/L, time25min, current density2.0A/dm2,temperature16℃；electrolysis coloring：Ag2SO41.0g/L, sulfuric20g/L, stabilizer15g/L, time60s, voltage10V；sealing treatment：de-ionized water, time30min,temperature95~98℃。SEM and EDS analysis showed that golden yellow films were very dense andsmooth, moreover Ag deposited in the bottom of films during electrolytic coloringprocess. EDS test indicated that films consisted mainly of A1and O element. XRDtesting results of golden yellow films showed that there were Al phase, γ-Al2O3phaseexisted in the films. The micro-hardness of golden yellow films improved greatly from 103.69HV of substrate to522.56HV respectively, and the friction coefficient reducedfrom0.45of substrate to0.2respectively. Corrosion resistance and of films was good.