高锰酸盐转化处理对医用AZ31B镁合金体外耐蚀性能的影响

Effect of Permanganate Conversion Treatment on in vitro Corrosion Resistance of AZ31B Magnesium Alloy

现有的医用镁及镁合金在植入人体后耐蚀性能较差。采用高锰酸盐在医用AZ31B镁合金表面制备氧化锰转化膜，并采用SEM、XRD、电化学测试及浸泡试验研究其性能，对膜的形貌、组分、电化学性能和耐体液腐蚀性能进行了探讨。结果表明：氧化锰转化膜均匀分布在AZ31B镁合金表面，无规则分布有微裂纹，膜厚约52-165μm；转化膜的主要成分包括MgO，MnO，MnO2，Mn2O3和Mn3O4；转化膜能够有效改善AZ31B镁合金的体外耐蚀性能。

Currently available Mg and Mg alloys for medical use possess poor corrosion resistance in human body. Thus a permanganate conversion fluid was adopted to prepare manganese oxide conversion coating on the surface of AZ31B magnesium alloy so as to improve the anticorrosion ability. The morphology and phase composition of as-prepared manganese oxide conversion coating were analyzed by scanning electron microscopy and X-ray diffraction,and the corrosion resistance of the conversion coating was evaluated based on electrochemical test and immersion test. Results indicated that as-prepared manganese oxide conversion coating was uniformly distributed on the surface of Mg alloy and had a thickness of about52 ~ 165 μm,and it contained a small amount of randomly distributed microcracks. In the meantime,as-prepared manganese oxide conversion coating was mainly composed of MgO,MnO,MnO2,Mn2O3and Mn3O4,and it was able to effectively improve the in vitro corrosion resistance of AZ31B Mg alloy.