Cl-和H+对2024-T3铝合金初期腐蚀的协同效应

摘要

The present work aims to explore the dual-factor synergistic effect of Cl-and H+concentrations.We obtained the polarization curve,open circuit potential and micro morphology of 2024-T3 aluminum alloy in aqueous solution with different Cl-and H+concentrations by means of electrochemical workstation,optical microscopy and scanning electron microscopy.A mathematical model was established for the analysis of dual-factor synergistic effect,and the main effect,synergistic effect and simple effect of Cl-and H+concentrations on the alloy's corrosion rate in the initial stage were quantified.We observed a corrosion acceleration but an unchanged apparent corrosion morphology while increased Cl-and H+concentrations.It can be concluded that,the main effect and synergistic effect of Cl-and H+concentrations on the corrosion rate are significant with the confidence level of 0.005,and the order from main to subordinate is H+,Cl-and H+×Cl-,and also there are significant differences between the simple effects of the two factors.In the initial stage,Cl-and H+affect the corrosion behavior of aluminum alloy by changing the passive film properties.Un-der different concentration levels,the disintegration of the passive film is dominated by distinct reactions:the dissolution damage un-der high H+concentration and the synergistic destruction of Cl-and H+under low H+concentration.%利用电化学工作站、光学显微镜和扫描电镜等设备,测量并观察了2024-T3铝合金在不同 Cl-和 H+浓度水溶液中的极化曲线、开路电位及微观腐蚀形貌;建立了用于双因素协同效应分析的数学模型,量化了 Cl-浓度和 H+浓度对铝合金初期腐蚀速率的主效应、协同效应以及简单效应,探讨了二者的协同作用机制.结果表明:Cl-和 H+浓度增加,铝合金腐蚀加剧,但表观腐蚀形貌未改变;置信度为0.005时,Cl-和 H+浓度对腐蚀速率的主效应及协同效应显著,由主到次可排序为 H+、Cl-、H+×Cl-(协同效应),二者的简单效应亦有显著性差异;二者通过改变钝化膜性质来影响铝合金初期的腐蚀行为,在不同浓度水平下,主导钝化膜破坏的反应有所不同,当H+浓度较高时,钝化膜的溶解破坏占据主导地位,当H+浓度较低时,Cl-和H+对钝化膜的协同破坏占据主导地位.