6A01-T5铝合金/304不锈钢的缝隙腐蚀行为研究

Crevice Corrosion Behavior of 6A01-T5 Aluminum Alloy/304 Stainless Steel

目的 研究6A01-T5铝合金和304不锈钢异种金属间的缝隙腐蚀行为规律。方法 采用常温常压浸泡腐蚀方法,结合SEM、EDS、XRD和白光干涉检测,对6A01-T5铝合金/304不锈钢缝隙结构在碱性Na Cl溶液中的腐蚀行为进行研究。结果 6A01-T5铝合金/304不锈钢缝隙腐蚀表现为在缝口处产生沿缝口方向的凹陷渠,在缝内,以局部减薄和腐蚀坑为主,并随着腐蚀时间的延长,腐蚀程度逐渐加重。不同区域腐蚀产物的形貌和成分组成不尽相同,缝外暴露区的腐蚀产物表现为晶体颗粒状,主要成分为Ca CO3和Al(OH)3等铝的腐蚀产物。缝口附近沿缝口方向形成一层有明显界线的腐蚀产物覆盖层,缝隙内部的腐蚀产物相对较少,表现为尺寸相对较小的结块,主要成分为Al(OH)3等铝的腐蚀产物。结论 在6A01-T5铝合金与304不锈钢非电连接情况下,6A01-T5铝合金/304不锈钢缝隙内2种金属分别独立发生缝隙腐蚀,因2种金属在腐蚀过程中争夺O2,使得304不锈钢对6A01-T5铝合金的缝隙腐蚀起到抑制作用。

The work aims to study the crevice corrosion behavior of 6A01-T5 aluminum alloy and 304 stainless steel.The corrosion behavior of 6A01-T5 aluminum alloy/304 stainless steel crevice structure in alkaline NaCl solution was studied by immersion corrosion method at normal temperature and pressure combined with SEM,EDS,XRD and white light interference detection.The crevice corrosion of 6A01-T5 aluminum alloy/304 stainless steel was manifested as a concave channel along the crevice direction,which was dominated by local thinning and corrosion pits in the crevice,and the corrosion degree gradually increased with the extension of corrosion time.The morphology and composition of the corrosion products in different areas were different.The corrosion products in the exposed area were crystalline particles,and the main components were CaCO3 and Al(OH)3 aluminum corrosion products.A layer of corrosion product covered with obvious boundary was formed in the crevice direction.The corrosion products inside the crevice were relatively few,composed of a relatively small-sized blocks,and the main components were Al(OH)3 and other related products.In the case of non-electric connection between 6A01-T5 aluminum alloy and 304 stainless steel,the two kinds of metals in the 6A01-T5 aluminum alloy/304 stainless steel crevice corrosion occurs independently.Because the two kinds of metals compete for O2 in the corrosion process,the 304 stainless steel can inhibit the crevice corrosion of 6A01-T5 aluminum alloy.