| Surface treatment was processd on aluminum alloy 5083 by microarc oxidation(abbreviated as MAO) technique in this paper. Different kinds of additives were added to investigate composition and performance of 5083 aluminum alloy micro-arc oxidation coating in silicate solution. Sealing treatment was applied to investigate the performance of micro-arc oxidation coating after sealing treatment.SEM, EDS and XPS were used to investigate the growth mechanism and composition of coating. Friction and wear test was applied to evaluate the mechanical properties of the coating. Potentiodynamic polarization curves, EIS, EN and the microstructure of the coating were applied to analysis the corrosion mechanism of micro-arc oxidation coating and evaluate the corrosion resistance of coating.The experimental results showed that components of the electrolyte could improve the corrosion resistance on microarc oxidation coating of Al alloy 5083.After adding KF solution,the F’ of KF solution and the Mg2+ of 5083 aluminum alloy could generate MgF2 which improved the corrosion resistance of coating.The WO42- of tungstate solution participated in the micro-arc oxidation process and generated WO3 and Al2(WO4)3 which increased the density of the coating and improved the corrosion resistance of coating. The study of friction and wear test showed that the average wear rate of coating was decreased significantly after micro-arc oxidation treatment and the wear resistance of coating was enhanced observably.With the increase of the content of tungstate in the electrolyte, the average wear rate of coating presented decreased and then increased which showed that the appropriate amount of tungstate could enhance the wear resistance of coating further. The studies of corrosion behavior showed that the corrosion resistance of 5083 al alloy was enhanced significantly by microarc oxidation technology. With the increase of the content of Na2WO4 in the electrolyte and oxidation time, the Dense layer resistance coating presented increased and then decreased which corresponded to the corrosion resistance of coating and became the main factor of the improvement of the corrosion resistance.The studies of the properties of coating after sealing treatment showed that the wear resistance of coating changed unconsciously after silane treatment. Silane treatment improved the porous layer resistance significantly and became the main factor of improvement of the corrosion resistance further. |
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