Prediction model for atmospheric corrosion of 7005-T4 aluminum alloy in industrial and marine environments

Abstract

Accelerated corrosion tests of the 7005-T4 aluminum alloy were conducted to determine a suitable service life prediction method by using alternating wet–dry cycles in three kinds of solutions. The morphology and composition analysis of the corrosion product revealed that slight corrosion occurred on the surfaces of the samples immersed in a 0.25wt% Na₂S₂O₈ solution. However, pitting corrosion occurred on the surfaces of the samples immersed in a 3.5wt% NaCl solution, whereas exfoliation corrosion occurred on the surfaces of the samples immersed in a mixture of 0.25wt% Na₂S₂O₈ and 3.5wt% NaCl solutions. A power exponent relationship was observed between the mass loss and exposure time of the 7005-T4 aluminum alloy immersed in the three kinds of solutions. In the mixture of 0.25wt% Na₂S₂O₈ and 3.5wt% NaCl solutions, the mass loss of the aluminum alloy yielded the maximum value. Based on the calculation of the correlation coefficients, the alternating wet–dry procedure in a 3.5wt% NaCl solution could be used to predict the corrosion behavior of 7005-T4 aluminum alloy exposed in the atmosphere of Qingdao, China. The prediction model is as follows: T = 104.28·t ^0.91, where T is the equivalent time and t is the exposure time.

Keywords

aluminum alloy / atmospheric corrosion / accelerated test / correlation coefficient / relational model

References

[1] Zheng C. B., Yan B. H., Zhang K., Yi G. Electrochemical investigation on the hydrogen permeation behavior of 7075-T6 Al alloy and its influence on stress corrosion cracking. Int. J. Miner. Metall. Mater., 2015, 22(7): 729.

[2] Beccaria A. M., Mor E., Poggi G. Examination of aluminium corrosion products in marine or industrial marine atmosphere. Mater. Corros., 1983, 34(5): 236.

[3] Lyon S., Thompson G., Johnson J., Wood G., Ferguson J. Accelerated atmospheric corrosion testing using a cyclic wet/dry exposure test: aluminium. galvanized steel, and steel, Corrosion, 1987, 43(12): 719.

[4] Li D. L., Fu G. Q., Zhu M. Y., Li Q., Yin C. X. Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere. Int. J. Miner. Metall. Mater., 2018, 25(3): 325.

[5] Foley R. T., Nguyen T. H. The chemical nature of aluminium corrosion V. Energy transfer in aluminium dissolution. J. Electrochem. Soc., 1982, 13(27): 464.

[6] Graedel T. Corrosion mechanisms for aluminium exposed to the atmosphere. J. Electrochem. Soc., 1989, 136(4): 204.

[7] Li T., Li X. G., Dong C. F., Cheng Y. F. Characterization of atmospheric corrosion of 2A12 aluminium alloy in tropical marine environment. J. Mater. Eng. Perform., 2010, 19(4): 591.

[8] Yang X. K., Zhang L. W., Zhang S. Y., Liu M., Zhou K., Mu X. L. Properties degradation and atmospheric corrosion mechanism of 6061 aluminium alloy in industrial and marine atmosphere environments. Mater. Corros., 2017, 68(5): 529.

[9] Blücher D. B., Svensson J. E., Johansson L. G. Influence of ppb levels of SO₂ on the atmospheric corrosion of aluminium in the presence of NaCl. J. Electrochem. Soc., 2005, 152(10): B397.

[10] Sun S. Q., Zheng Q. F., Li D. F., Wen J. G. Long-term atmospheric corrosion behaviour of aluminium alloys 2024 and 7075 in urban, coastal and industrial environments. Corros. Sci., 2009, 51(4): 719.

[11] Kouřil M., Novák P., Bojko M. Threshold chloride concentration for stainless steels activation in concrete pore solutions. Cem. Concr. Res., 2010, 40(3): 431.

[12] Ebrahimi N., Moayed M. H., Davoodi A. Critical pitting temperature dependence of 2205 duplex stainless steel on dichromate ion concentration in chloride medium. Corros. Sci., 2011, 53(4): 1278.

[13] Hastuty S., Nishikata A., Tsuru T. Pitting corrosion of Type 430 stainless steel under chloride solution droplet. Corros. Sci., 2010, 52(6): 2035.

[14] Deng B., Jiang Y. M., Gong J., Zhong C., Gao J., Li J. Critical pitting and repassivation temperatures for duplex stainless steel in chloride solutions. Electrochim. Acta., 2008, 53(16): 5220.

[15] Souza E. C., Rossitti S. M., Rollo J. M. D. A. Influence of chloride ion concentration and temperature on the electrochemical properties of passive films formed on a superduplex stainless steel. Mater. Charact., 2010, 61(2): 240.

[16] Arshadi M. A., Johnson J. B., Wood G. C. The influence of an isobutane-SO2 pollutant system on the earlier stages of the atmospheric corrosion of metals. Corros. Sci., 1983, 23(7): 763.

[17] Syed S. Atmospheric corrosion of carbon steel at marine sites in Saudi Arabia. Mater. Corros., 2015, 61(3): 238.

[18] Corvo F., Perez T., Dzib L. R., Martin Y., Castañeda A., Gonzalez E., Perez J. Outdoor-indoor corrosion of metals in tropical coastal atmospheres. Corros. Sci., 2008, 50(1): 220.

[19] de la Fuente D., Otero-Huerta E., Morcillo M. Studies of long-term weathering of aluminium in the atmosphere. Corros. Sci., 2007, 49(7): 3134.