| ZHANG Shu-fang,ZHAO Long-zhi,ZHANG Rong-fa,ZHAO Rong-fang,LI Guo-qiang,SHI Xiao-ting.Effect of EDTA-CuNa2 on the Performance of Micro-arc Oxidation Film Formed on Medical Magnesium Alloys[J],50(2):48-57, 73 |
| Effect of EDTA-CuNa2 on the Performance of Micro-arc Oxidation Film Formed on Medical Magnesium Alloys |
| Received:April 07, 2020 Revised:June 15, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.02.006 |
| KeyWord:magnesium alloys copper-containing oxidation film corrosion resistance impedance Tafel |
| Author | Institution |
| ZHANG Shu-fang |
School of Materials Science and Engineering, East China Jiaotong University, Nanchang , China;School of Materials and Electromechanics, Jiangxi Science & Technology Normal University, Nanchang , China |
| ZHAO Long-zhi |
School of Materials Science and Engineering, East China Jiaotong University, Nanchang , China |
| ZHANG Rong-fa |
School of Materials and Electromechanics, Jiangxi Science & Technology Normal University, Nanchang , China |
| ZHAO Rong-fang |
School of Materials and Electromechanics, Jiangxi Science & Technology Normal University, Nanchang , China |
| LI Guo-qiang |
School of Materials and Electromechanics, Jiangxi Science & Technology Normal University, Nanchang , China |
| SHI Xiao-ting |
School of Materials and Electromechanics, Jiangxi Science & Technology Normal University, Nanchang , China |
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| Abstract: |
| 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 potentialof 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 difficult for Cu ions to participate in film formation, on account of the corrosion of EDTA ions and Cu ions. |
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