Effect of Solution pH on Exfoliation Corrosion of 2A12-T4 Aluminum Alloy under Full-Immersion Corrosion Condition

EXCO standard solution (pH 0.4) was used as the basic solution, and the influence of solution pH on the exfoliation corrosion behavior of 2A12-T4 aluminum alloy under full immersion corrosion conditions was studied by changing the solution pH to 1 and 2. The results showed that with the increase of solution pH, the mass reduction of samples at the initial stage of corrosion and the mass increment at the later stage of corrosion were significantly reduced, the degree of exfoliation corrosion was significantly weakened, and the overall exfoliation corrosion was transformed to localized exfoliation corrosion. The exfoliation corrosion propagation characteristics on the cross section of samples in the solutions with different pH were basically the same.In the test solution with pH=1, after 192 h of corrosion, the intergranular corrosion characteristics of the denuded extension zone of the sample were very similar to those in Hainan Wanning Natural Environment Test Station for 7 years, and they were all localized exfoliation corrosion.