镁及镁合金在仿生体液中的腐蚀降解行为

Corrosion behavior of magnesium and its alloy in simulated body fluid

目的:观察纯镁及镁锌系列合金在仿生体液中的腐蚀行为,分析其是否具有生物临床应用价值。方法:实验采用纯镁(99.9%)、镁锌锆(ZK60)、镁锌锆钇(Mg-5.6Zn-0.55Zr-0.9Y)3种合金材料,将试样分别放入仿生溶液中浸泡10d,仿生溶液恒温(37.0±0.5)℃。用BP211D电子天平测量了试样在仿生体液中的腐蚀失重,用LK98BII型电化学系统测量了试样在仿生体液中腐蚀时的Tafel曲线,同时观察仿生溶液pH值的变化结果:①在仿生体液中242h后,纯镁、镁锌锆和镁锌锆钇损失量分别为0.9%,3.1%和抗蚀性1.7%。②在实验条件下,腐蚀电流密度纯镁为2.03mA/mm2,镁锌锆为10.14mA/mm2,镁锌锆钇为4.42mA/mm2。③随着镁合金在仿生体液中浸泡时间延长,溶液的pH值增高,电势也随着pH值的增加而减小,镁及镁合金的腐蚀速率会降低。结论:①合金中杂质元素越少,耐腐蚀性能越好,选择纯镁或含Y的镁合金作为镁基生物材料的耐蚀性较好。②在镁锌合金中添加钇后其耐体液腐蚀性能得到了改善。

AIM： To observe the corrosion behavior of pure magnesium and magnesium alloys in simulated body fluid, and explore whether the magnesium alloys are suitable for clinical biomedical application. METHODS： The pure magnesium （99.9%）, magnesium-zinc-zirconium （Mg-Zn-Zr, ZK60） and Mg-Zn-Zr-Yttrium （Mg-5.6Zn-0.55Zr-0.9Y） were put in simulated body fluid for 10 days at （37.0＋0.5）℃. The corrosion weight loss was measured by BP211D electronic balance, and the Tafel curve was drawn during corrosion by LK98B Ⅱ electrochemical system; pH value fluctuation of the simulated body fluid was recorded simultaneously. RESULTS： （1）Immersing in the stimulated body fluid for 242 hours, the corrosion weight loss of pure magnesium, -ZK60, and Mg-5.6Zn-0.55Zr-0.9Y was 0.9%, 3.1% and 1.7% respectively. （2）Under the experiment condition, the corrosion current density was 2.03 mA/mm^2 for pure magnesium, 10.14 mA/mm^2 for ZK60, and 4.42 mA/mm^2 for Mg-5.6Zn-0.55Zr-0.9Y. （3）With the soaking time in fluid increasing, the pH value of the solution increased, which decreased the electromotive force, leading to the reduction in corrosion rate of magnesium and its alloys. CONCLUSION： （1）The purer the magnesium alloys, the better the corrosion resistance is. The corrosion resistance of pure magnesium or Mg-Y alloy as the magnesium-derived biomaterial is good. （2）The corrosion resistance of Mg-Zn alloy is improved by adding Y.