| Magnesium alloys which are compared as the"21st Green Engineering Material" arewidely used in many industries. But the standard electrode potential of magnesium is lowand the chemical stability of magnesium alloys is poor．So far, the poor corrosionresistance greatly limits the application of magnesium alloy. Surface treatment ofmagnesium alloy is an effective means to improve the corrosion resistance of magnesiumalloys.This paper studied the change of corrosion resistance of Mg alloys by the micro-arcoxidation and sol-gel method．The electrolyte of micro-arc oxidation is alkaline silicatesolution, and studied the effect of glycerol to the film. The optimal concentration ofglycerol is6mL·L-1After micro-arc oxidation we get an oxide ceramic layer on thesurface of magnesium alloy.There are many of pores on the micro-arc oxidation ceramic coating, which provide achannel for corrosive media into the magnesium alloy substrate. So it is quite important toperform sealing treatment for magnesium alloy which after micro-arc oxidation. Sol-gelmethod is a promising and environmentally friendly method for preparing coating. In thispaper, it uses titanium solution coating on magnesium alloy micro-arc oxidation ceramiccoatings.The optimum conditions for the thin film were obtained as following: water was7mL; ethanol was33mL; drying temperature was100℃; drying time was25min; agingtime is three days; calcination temperature was330℃; dipping time was4.The surface morphology, chemical composition and corrosion resistance of themicro-arc oxidation ceramic coating and the micro-arc/sol composite film by usingscanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS)polarization curves and electrochemical impedance test. The results show that aftermicro-arc oxidation/sol-gel treatment and the dense and the corrosion resistance of thefilm has been greatly improved compared with micro-arc oxidation ceramic coatings... |
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