镁合金表面铁氧化物涂层的制备及其耐蚀性能

镁合金的耐蚀性差,严重限制了其在生物材料领域的应用。在镁合金表面采用化学还原法和溶剂热法复合制备了铁氧化涂层,利用扫描电镜(SEM)、X射线衍射(XRD)和能谱(EDS)等对样品的结构与组成进行表征,分别采用Tafel测试和磷灰石诱导试验评价了样品的耐蚀性和生物相容性。结果表明:涂层的主要组分为Fe3O4、Fe2O3和FeO;随着乙醇浓度降低和溶剂热时间延长,涂层粗糙度先降低后升高;Tafel测试表明,随着乙醇浓度的增加,涂层的耐蚀性先增高后降低;在乙醇浓度为90%,溶剂热时间4 h时获得的涂层表面无脱落现象,微裂缝数量最小,具有最高的耐腐蚀性能,极化电阻达51 779.2Ω,并具有良好的生物诱导活性。

Preparation and Corrosion Resistance of Iron Oxide Coatings on MB31 Magnesium Alloy

In order to improve the corrosion resistance of magnesium alloys,the iron oxide coatings were prepared by chemical reduction/solvothermal methods.The composition and structure of coatings were studied by SEM,XRD and EDS.In addition,the corrosion resistance and biocompatibility of coatings were evaluated by Tafel curves and apatite-inducing tests.Results showed that the as-obtained coatings were composed of Fe3O4,Fe2O3 and FeO.With the decrease of ethanol concentration and the increase of reaction time,the roughness of coatings reduced firstly and then increased.Tafel curves indicated the corrosion resistance of coatings increased firstly and then decreased,as the ethanol concentration was improved.The coating prepared with ethanol concentration of 90%for 4h possessed the least micro-cracks and no abscission was observed.Therefore,the coating had the optimal corrosion resistance,and its polarization impedance was 51779.2Ω.Furthermore,the coating also possessed good biocompatibility.