Mg-14Li-1Al-0.1Ce合金在NaCl溶液中的腐蚀行为

采用电化学方法研究了Mg-14Li-1Al-0.1Ce合金在NaCl溶液中的腐蚀行为,采用扫描电镜观察腐蚀后的表面形貌,用失重法测试腐蚀速率,用X射线衍射(XRD)分析了腐蚀层和溶液中腐蚀颗粒的组成。结果表明,Mg-Li-Al-Ce合金的腐蚀速率随溶液Cl-浓度增大而增大,由失重法所得到的腐蚀速率远大于由腐蚀电流密度(Jcorr)计算所得的腐蚀速率。扫描电镜(SEM)观察表明,合金表面随溶液Cl-浓度增加而破坏严重。腐蚀产物层没有保护作用,在腐蚀产物下有明显的蚀坑和裂纹。XRD表明腐蚀产物层和溶液中腐蚀颗粒由Mg(OH)2、Li0.92Mg4.08和Li3Mg7组成。

Corrosion Behaviors of Mg-14Li-1Al-0.1Ce Alloy in NaCl Solutions

The corrosion characteristics of Mg-14Li-1Al-0.1Ce alloy in NaCl solutions were investigated by electrochemical measurements.The morphology of corroded surface was observed by scanning electron microscopy(SEM),the corrosion rates were investigated by weight-loss method and XRD was used to analyze the composition of corrosion layer and corrosion products deposited in solution.The results showed that the corrosion resistance of Mg-Li-Al-Ce alloy gradually deteriorated with increasing the concentration of Cl-.The corrosion rate of Mg-Li-Al-Ce alloy evaluated by Tafel extrapolation from polarization curves was much lower than that evaluated by weight-loss method.SEM observation showed that the alloy surface was broken more severely in higher Cl-concentration solutions.The corrosion layer formed on the surface of alloy could not inhibit corrosion,after removing the corrosion products attached on the alloy surface,deep pits and cracks were observed.Both corrosion layer and corrosion products deposited in solution consisted of Mg(OH)2,Li0.92Mg4.08 and Li3Mg7.