| The current study found that using the AC plasma micro-arc oxidation processing method could form a thick layer which could be more than35μm at the surface of the AZ91D magnesium alloy within120seconds. But there is a serious loose from the thick layer. Desertification phenomenon of surface thick layer almost has no protective effect on magnesium alloy magnesium alloy substrate.In order to delay the occurrence of the desertification phenomenon and protect the magnesium alloys, we must strengthen and improve the protective layer of sintered. That will improve the maximum thickness of the thick layer of the surface. Surface treatment of magnesium alloy, when it reaches a certain thickness, the agglomeration phenomenon would occur. During the surface treatment, if oxygen is injected into the electrolyte, the high temperatures will cause the oxygen form a large number of oxygen plasma.And oxygen plasma will help enhance and improve the agglomeration effect. Therefore we can make use of sintering aids role of the protective layer, the oxygen plasma on the surface treatment parameters optimized combination, delay the occurrence of agglomeration phenomenon, so as to achieve the purpose of further increasing the maximum thickness of the thick layer of the surface which has a protective effect.Using the film porosity as an indicator, we can determine the optimal parameter combination of magnesium alloy micro-arc oxidation: Potassium fluoride concentration of490g/L, potassium hydroxide concentration of250g/L, and power frequency AC voltage110V, per liter of handling liquid oxygen is injected into the amount of0.01L/s processing time of160s. Compared with the original study, the treatment time is40s longer, and the thick layer thickness change from35μm to65μm, the thickness of the porous layer is maintained at less than1μm, so that we solved the desertification effect of the thick layer. The research results provide helpful information to magnesium alloy micro-arc oxidation technology. |
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