镁合金磷化工艺及耐蚀性研究

Studies on Phosphating Treatments and Corrosion Resistance of Film for Magnesium Alloys

采用磷酸盐体系对镁合金表面进行磷化处理,并对磷化配方进行优化.利用扫描电镜(SEM)观察膜层形貌,用极化曲线方法对不同工艺下得到的磷化膜进行耐腐蚀性能分析.结果表明,镁合金表面经过优化配方处理后,磷化膜均匀、细小、致密,膜层主要由锰的磷酸盐构成,富含氧、磷、锰等元素,完全不含Mg和Al.优化配方磷化后的镁合金表面在3.5%NaCl溶液中浸泡24 h,耐腐蚀性能显著提高,并确定了最佳工艺条件为:温度60℃、时间60 min、pH值3.

Using phosphate salt series, the surface of magnesium alloys is phosphated and phosphating formula is optimized. Scanning electron microscope （SEM） is adopted to study phosphate conversion films and polarization curve method is used to analyze the ccorrosion resistance of phosphate conversion films produced by using different technologies. The results show that phosphate conversion film of themagnesium alloy surface which is optimized is uniform, fine and compact. In addition, the film composed of manganese phosphates is rich in oxygen, phosphor and manganese, without any Mg or Al. When this magnesium alloy surface is dipped in liquor, 3.5 per cent of which is NaCl for 24 hours, the corrosion resistance is considerably improved. The optimum conditions are that temperature is 60 ℃, time 60 minutes, pH value 3.