Mg-11Li-3Al-0.5RE合金在酸性NaCl溶液中腐蚀特性研究

Study on Corrosion Characteristic of Mg-11Li-3Al-0.5RE Alloy in Acidic Solution of NaCl

为研究Mg-11Li-3Al-0.5RE合金在酸性NaCl溶液中的腐蚀特点,采用静态失重法和电化学方法对合金的腐蚀行为进行测试,并用SEM、XRD分别分析了腐蚀形貌和腐蚀产物。结果表明:在酸性NaCl溶液中,随着Cl-含量的升高,合金的平均腐蚀速率增大,腐蚀电位负移,体系中Rsol、Rt、Rf减小,腐蚀越严重;pH值减小时,合金的腐蚀电流增大,线性极化电阻减小,加快了腐蚀的进行。在酸性环境中,Mg-11Li-3Al-0.5RE合金腐蚀后形成较大、较深的蚀坑,腐蚀产物主要为Mg(OH)2和Al2O3。

Corrosion behavior of Mg-11Li-3Al-0.5RE alloy in acidic solution of NaCl was investigated by means of weight loss and electrochemical means. The corrosion appearance and corroded surface were analyzed by using SEM and XRD. The results showed that the average corrosion velocity of Mg-11Li-3Al-0.5RE alloy increased, nevertheless the pitting corrosion potential, Rsol, Rt, and Rf decreased when the concentration of Cl- increased in acidic solution of NaCl. This means that corrosion developed more seriously with the increase of Cl- concentration. The corrosion current gradually increased while linear resistance decreased with the decrease of pH value, so that the corrosion reaction was picked up. In acidic solution of NaCl, the deep corrosion pits were formed after corrosion experiments, and the corrosion products on alloys surface were mainly consisted of Mg（ OH）2 and Al2O3.