金属阳离子对医用镁合金降解行为的影响规律

Effect of Different Metal Cations on the Degradation Behavior of Biomedical Magnesium Alloy

医用镁合金的降解特性直接影响其在心血管支架和骨替换材料等领域的应用。本研究在保持与生理体液氯离子浓度一致的基础上,选用镁合金AZ31B分别浸入NaCl溶液,KCl溶液,MgCl2溶液和CaCl2溶液中,对比研究金属阳离子对医用镁合金的降解行为影响。通过动电位极化曲线和电化学阻抗谱测试分析,发现镁合金浸泡在4种氯盐溶液时的腐蚀电位、阻抗与其在降解过程中溶液pH变化、样品失重变化趋势一致,即金属阳离子直接影响医用镁合金的降解特性:NaCl>KCl>CaCl2>MgCl2,其中Na+和K+比Ca2+和Mg2+更能促进镁合金降解。

The degradation property of biomedical magnesium alloy is the key to determine its application on cardiovascular stents and bone replacement material, etc. In this paper, we discussed the effect of degradation on magnesium alloy with various cations. AZ31 B magnesium alloy samples were immersed into NaCl aq., KCl aq., MgCl2 aq. and CaCl2 aq. with the same concentration of Cl- used as body fluid. The potentiodynamic polarization curve（PPC） and electrochemical impedance spectroscopy（EIS） of these magnesium samples were analyzed. Results show that the corrosion potential and impedance have the similar tendency with the p H values and gravimetric curve. Namely, the metal cations affect the degradation property of magnesium alloy directly and the order is NaCl KCl CaCl2 MgCl2. Na＋ is superior to other cations in magnesium alloy degradation.