固溶处理对Mg-3Gd-1Zn合金在模拟体液中腐蚀性能的影响

目的探究固溶处理对Mg-3Gd-1Zn生物镁合金腐蚀性能的影响规律。方法对Mg-3Gd-1Zn镁合金进行不同温度的固溶处理,随后进行时效处理。采用扫描电镜(SEM)对合金的显微组织进行观察,利用失重法和析氢法测试合金在模拟体液(SBF)中的腐蚀性能,利用极化曲线和交流阻抗谱对合金的电化学行为进行评估。结果由失重法计算结果可知,T6-460、T6-510、T6-520和T6-530合金在SBF中浸泡120h后的腐蚀速率分别为2.48、1.19、0.86、1.17 mm/a,即随着固溶温度的增加,合金的腐蚀速率顺序为:T6-460T6-510T6-530T6-520。析氢测试结果表明,随着浸泡时间的增加,T6-460与T6-510合金的腐蚀速率升高,而T6-520与T6-530合金的腐蚀速率变化较小,浸泡120 h后的析氢分析结果与失重法计算结果趋势一致。电化学测试表明,T6-460、T6-510、T6-520和T6-530合金的电流密度分别为8.01×10~(-5)、3.85×10~(-5)、3.30×10~(-5)、3.90×10~(-5)A/cm~2。随着固溶温度的增加,合金的容抗弧半径先增加后减小。合金在腐蚀过程中发生了点蚀。结论四种测试方法均表明T6-520镁合金表现出最佳的耐蚀性。

Effects of Solution Treatment on Corrosion Properties of Mg-3Gd-1Zn Alloy in Simulated Body Fluid

The work aims to investigate the effect of solution treatment on the corrosion properties of Mg-3Gd-1Zn bio-magnesium alloy. The Mg-3Gd-1Zn alloy was performed by solution treatment at different temperature and then aged. The mi-crostructure of alloys was observed by scanning electron microscopy (SEM). The corrosion properties of Mg-3Gd-1Zn alloys in the simulated body fluid (SBF) were tested by mass loss and hydrogen evolution and the electrochemical behavior was evaluated by polarization curves and electrochemical impedance spectroscopy. The mass loss tests results showed that the corrosion rates of T6-460, T6-510, T6-520, and T6-530 alloys after immersed in SBF for 120 h were 2.48, 1.19, 0.86, and 1.17 mm/a, respectively. As the solution temperature increased, the corrosion rates of the alloys followed the order: T6-460 > T6-510 > T6-530 > T6-520. The hydrogen evolution results showed that the corrosion rates of T6-460 and T6-510 alloys increased with the increase of immersion time, while the corrosion rates of T6-520 and T6-530 alloys changed slightly. The corrosion rate trend obtained by hydrogen evolution after immersion for 120 h and mass loss were consistent. The electrochemical tests indicated that the current densities of the T6-460, T6-510, T6-520, and T6-530 alloys were 8.01×10?5, 3.85×10?5, 3.30×10?5 and 3.90× 10?5 A/cm2, respectively. As the solution temperature increased, the radius of the capacitive arc of the alloy increased first and then decreased and the pitting corrosion occurred during the corrosion process. T6-520 exhibited the best corrosion resistance based on all the four methods.