表面缺陷形貌对AZ31镁合金腐蚀行为的影响研究

Effect of Surface Defect Morphology on Corrosion Behavior of AZ31 Magnesium Alloy

为了研究带有犁沟类表面缺陷的轧态AZ31镁合金在典型海水服役环境中的腐蚀行为规律,通过预制可模拟量化的划痕缺陷,采用浸泡失重法和电化学测试分析法,并基于正交分析法,以腐蚀时间为比照,分析其腐蚀行为对此类缺陷宽度的敏感程度。结果表明,当犁沟宽度为4μm时,镁合金的初期腐蚀速率显著升高,稳定腐蚀阶段(5h)随划痕宽度增加,镁合金腐蚀倾向和腐蚀速率变大,耐腐蚀性降低,腐蚀产物主要为白色片状的Mg(OH)2;缺陷宽度与腐蚀时间的显著性相当,为使用AZ31镁合金提供了缺陷宽度理论数值。

In order to study the corrosion behavior of rolled AZ31 magnesium alloy with furrow surface defects in the typical seawater service environment,the immersion weight loss method and electrochemical test analysis method are used to analyze the sensitivity of corrosion behavior to the width of such defects through the prefabrication of quantifiable scratch defects and based on the orthogonal analysis method and corrosion time.The results show that when the width of furrow is 4μm,the initial corrosion rate of magnesium alloy increases significantly.With the increase of scratch width in the stable corrosion stage(5 h),the corrosion tendency and corrosion rate of magnesium alloy increase,and the corrosion resistance decreases.The corrosion products are mainly white flake mg(OH)2.The defect width is similar to the corrosion time.