Corrosion behavior of 2A12 and 5A02 aluminum alloy in typical marine atmosphere environment
Songze Wu, C.Y. Liu, Kun Zhou, Ying Li, Zequn Zhang, Bowei Zhang, Junsheng Wu
Abstract
The corrosion behavior of 2A12 and 5A02 aluminum alloys in Wenchang marine atmospheric environment was systematically investigated by means of macroscopic morphology observation, microscopic corrosion morphology analysis, pitting analysis, weight loss analysis and electrochemical measurements. Experimental results demonstrated that both alloys exhibited pronounced pitting corrosion, with corrosion products primarily consisting of Al 2 O 3 and AlO(OH). After 48 months of outdoor exposure, 5A02 developed a 25 μm-thick corrosion product layer, while 2A12 displayed a significantly thicker layer (70 μm) accompanied by greater average pitting depth and pit density. Corrosion rates for both alloys followed a similar trend of initially increasing, then decreasing and finally stabilizing, the maximum corrosion rate for 2A12 (32.57 g/m 2 •a) far exceeded that of 5A02 (2.04 g/m 2 •a). Electrochemical analysis revealed progressive enhancement of corrosion resistance over time for both alloys, evidenced by increasing polarization resistance (R p ) values. Throughout the exposure period, 5A02 consistently maintained higher R p values compared to 2A12, conclusively demonstrating its superior corrosion resistance in marine atmospheric environments.