Investigation of 7075 Aluminum Alloy Corrosion in Marine Environment
Huan Sheng Lai, Xiaowei Jiang, Huali Li, Hongyuan Cui, Zilong Zhao, Hui Guo, Liang Li
Abstract
Aluminum alloys have been widely used in the automotive, marine, and aerospace industries due to lightweight and satisfactory mechanical performance. However, their applications are greatly limited by corrosive-resistance performance. In this work, the corrosion mechanism of 7075 aluminum alloy is systematically investigated in two corrosive marine environments: simulated seawater and real seawater. Results show that the alloy had a faster corrosion rate by yielding much deeper corrosion holes in the real seawater than the simulated media. Moreover, there is a lower corrosion voltage and higher corrosion current in the real sea water, which accounts for the corrosion-resistance performance. In addition, the diverse corrosion products in the real seawater also provide an evidence of different corrosion mechanisms. From these phenomena, it is speculated that the presence of microorganisms in real seawater may lead to microbial corrosion and increase the active sites of the alloy surface, therefore accelerating the local corrosion of the alloy surface.