摘要
采用电化学测试、共聚焦显微镜、扫描电子显微镜等手段,研究硝酸根和电偶对7075-T651高强铝合金缝隙腐蚀行为影响。结果表明,硝酸根作为氧化剂能促进铝合金表面形成保护性的氧化膜,有效抑制铝合金的腐蚀。然而,当存在缝隙结构时,在没有硝酸根的溶液中,缝隙内没有发生明显腐蚀现象。而在含有硝酸根溶液中,硝酸根还原产生的氨气将富集在缝隙内,并选择性溶解含铜颗粒,诱发缝隙内点蚀形核,促进缝隙腐蚀发展。与304不锈钢偶接后,使缝隙内外电极之间产生较大的电偶腐蚀驱动力,加速缝隙内金属溶解及溶液劣化过程,从而导致更严重的缝隙腐蚀。
The effect of the presence of nitrate and galvanic couple on the crevice corrosion behavior of 7075-T651 Al-alloy in 3.5%NaCl solution is investigated by the electrochemical tests and surface analysis techniques.The results indicate that the nitrate as an oxidizing agengt could promote the formation of passive film,so that inhibit the corrosion of the Al-alloy.However,when there is a formed crevice on the Al-alloy in a solution without nitrate,inside the crevice corrosion is hard to occur and develop,in the contrast,in a solution with the presence of nitrate,which could be reduced forming NH3,the later agent may accumulate inside the crevice and selectively dissolve the copper particles,thereby induced the nucleation of pitting corrosion,afterwards,further promoted the propagation of crevice corrosion.After coupling with 304 stainless steel,a large Galvano-corrosion driving force is generated between the electrodes inside and outside the crevice,which accelerates the metal dissolution and solution deterioration process in the crevice,resulting in much more serious crevice corrosion in the solution with nitrate.
作者
乔泽
李清泉
刘晓航
李燚周
QIAO Ze;LI Qingquan;LIU Xiaohang;LI Yizhou(Fujian Fuqing Nuclear Power Co.,Ltd.,Fuqing 350318,China;Jiangsu Nuclear Power Co.,Ltd.,Lianyungang 222042,China;School of Materials Science and Engineering,Ocean University of China,Qingdao 266100,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2024年第4期1047-1054,共8页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金(51901217)。
