摘要
The corrosion evolution of 2024-T351 and 7075-T651 aluminum alloys in the thin electrolyte layer(TEL)and wet-dry alternating cycle(WDAC)environment is studied in this work.The results show that in the TEL environment,the competitive effect between H+that accelerates corrosion reactions and deposition of aluminum sulfate that impedes corrosion attacks exists during the corrosion exposure.The difference is that with increasing HSO_(3)^(-),subsurface intergranular corrosion on 2024-T351 is promoted to form exfoliation corrosion eventually and the degree of exfoliation corrosion begins to decrease because the blocking effect of aluminum sulfate exceeds the expediting effect of H+.For 7075-T651,the corrosion area and the corrosion diameter decrease gradually,which is attributed to the HSO_(3)^(-)-enhanced deposition of corrosion products and their blocking effect.In the WDAC environment,the corrosion processes of 2024-T351 and 7075-T651 are the acidic dissolution of the matrix during the soaking phase.When the HSO_(3)^(-)concentration is high enough(0.1 M),the inhibiting effect of aluminum sulfate becomes the dominant factor.
基金
The authors wish to acknowledge the financial support of the Natural Science Foundation of China(No.51931008)
the Ministry of Industry and Information Technology Project(No.MJ-2017-J-99),and the Shandong Provincial Key R&D plan(No.2019GHY112050).
