EDTA-CuNa2对医用镁合金微弧氧化膜性能的影响  

Effect of EDTA-CuNa2 on the Performance of Micro-arc Oxidation Film Formed on Medical Magnesium Alloys

作　　者：张淑芳 赵龙志 张荣发 赵融芳 李国强 师晓亭 ZHANG Shu-fang;ZHAO Long-zhi;ZHANG Rong-fa;ZHAO Rong-fang;LI Guo-qiang;SHI Xiao-ting(School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,China;School of Materials and Electromechanics,Jiangxi Science&Technology Normal University,Nanchang 330013,China)

机构地区：[1]华东交通大学材料科学与工程学院,南昌330013 [2]江西科技师范大学材料与机电学院,南昌330013

出　　处：《表面技术》2021年第2期48-57,73,共11页Surface Technology

基　　金：江西省教育厅基金项目(GJJ180617);国家自然科学基金项目(51361011,51861007)。

摘　　要：目的在镁合金表面生成一层含铜氧化膜,以提高镁合金的耐蚀性和抗菌性。方法利用微弧氧化技术在镁合金表面生成含铜氧化膜,用SEM、EDS和电化学工作站研究含铜电解质浓度对镁合金氧化膜的表面形貌、成分和耐蚀性的影响,及含铜氧化膜的腐蚀机理。结果随着EDTA-CuNa2浓度的增加,一方面,更多的Cu/Mg构成微电偶腐蚀电池,加速镁合金的腐蚀;另一方面,析出的Cu覆盖在镁合金基体表面对镁合金起着保护作用,同时由于Cu的电位更正,促使镁合金的腐蚀电位正移,降低镁合金腐蚀倾向。EDTA离子是一种腐蚀性介质,0.01 mol/L EDTA–的腐蚀性比3.5%NaCl略强。随着EDTA-CuNa2浓度的增加,溶液中含有更多的EDTA离子和Cu离子,导致镁合金基体的腐蚀电流增大,耐蚀性降低。镁合金在含EDTA-CuNa2的电解质中氧化时,由于EDTA离子和Cu离子共同对镁合金腐蚀导致Cu离子难以参与成膜。EDTA离子和铜离子对镁合金均具有腐蚀作用,所以限制了铜离子进入氧化膜中。结论随着EDTA-CuNa2浓度的增加,氧化膜中的铜元素含量缓慢增加,氧化膜的腐蚀电位正移,腐蚀电流密度变化不大。Due to its excellent properties such as the degradability,magnesium alloys have become a hotspot in biomedical materials research,but the poor corrosion resistance seriously restricts their development.The paper aims to improve the corrosion resistance and antibacterial property of the magnesium alloys by preparing copper-containing anodic coatings using micro-arc oxidation(MAO)treatment.The effects of the copper-containing electrolyte concentration on the surface morphology,composition and corrosion resistance of the oxidation film on magnesium alloy as well as the corrosion mechanism of copper-containing oxidation film were investigated by SEM,EDS and electrochemical workstation.In addition,the corrosion mechanism of MAO coatings was further clarified.The result shows that magnesium alloy is corroded by both EDTA ions and Cu ions,which restricts the Cu ions into the oxidation film.With increased EDTA-CuNa2 concentration,the content of copper element slowly increases,the corrosion potential of the oxidation film moves towards positive direction,but the corrosion current density changes little.On the one hand,more Cu/Mg constitutes a microcouple corrosion battery with the increase of EDTA-CuNa2 concentration,accelerating the corrosion of magnesium alloys.On the other hand,the precipitated Cu covers the surface of magnesium alloys and plays a protective role on the magnesium alloys.At the same time,due to the corrosion potential of Cu is more positive than Mg,which results in the corrosion potential of magnesium alloy moving toward positive direction and the corrosion tendency of magnesium alloys is decreased.EDTA ion is a corrosive medium,the corrosivity of 0.01 mol/L EDTA–is a little stronger than that of 3.5%NaCl.With the increase of EDTA-CuNa2 concentration,the solution contains more EDTA ions and Cu ions,which eventually leads to the increase of corrosion current and the decrease of corrosion resistance of magnesium alloys.When magnesium alloys are oxidized in the electrolyte containing EDTA-CuNa2,it’s di

关 键 词：镁合金 含铜氧化膜 耐蚀性 阻抗 极化曲线 

分 类 号：TG174.4[金属学及工艺—金属表面处理]