摘要
将镁合金置于浓度为10 mol/L的KOH溶液中,在1.0 V电压下电化学阳极氧化,然后在723 K温度下热处理1 h,在镁合金表面制备氧化镁(MgO)涂层,用扫描电镜(SEM)和X射线衍射(XRD)对涂层进行形貌表征和物相分析,研究有MgO涂层的镁合金在Hank模拟体液中的动态阳极极化曲线和浸泡3 d溶液pH值的变化,通过SEM观察腐蚀后样品的形貌并进行成分分析,探讨腐蚀机理。结果表明:与裸合金相比,有MgO涂层的镁合金的腐蚀电位正移130 mV,腐蚀电流减少2个数量级,腐蚀过程主要发生在氧化镁涂层并且没有明显的点蚀现象,表明有MgO涂层的镁合金具有优异的抗腐蚀性能。
MgO coating was prepared on Mg alloy by anodic electrodeposition at 1.0 V in KOH solution with concentration of 10 mol/L and subsequent heat treatment in air at 723 K for 1 h.SEM and XRD were used to characterize the morphology and composition of as-prepared MgO coating.Potentiodynamic polarization and pH value changes with time were studied for MgO coated Mg alloy in Hank’s SBF.The results show that the corrosion potential for MgO coated Mg alloy has positively shifted 130 mV and the corresponding corrosion current density decreases two orders compared with the bare Mg alloy.Meanwhile,the corrosion occurs mainly on MgO coating and no significant pitting corrosion is observed.As a result,the Mg alloy with MgO coating shows enhanced corrosion resistance.This is likely because the MgO coating on the Mg alloy surface may serve as a barrier,which could effectively block the direct contact of underlying Mg matrix and solution,and thus the corrosion rate is decreased.
出处
《粉末冶金材料科学与工程》
EI
2010年第3期271-276,共6页
Materials Science and Engineering of Powder Metallurgy
基金
国家杰出青年科学基金资助项目(50825102)
国家自然科学基金委员会创新研究群体基金资助项目(50721003)
中南大学粉末冶金国家重点实验室开放基金资助项目
