Effects of Anodizing Parameters in Tartaric-Sulphuric Acid on Coating Thickness and Corrosion Resistance of Al 2024 T3 Alloy

Mohammad Zaki Mubarok^1*,   Wahab²,   Sutarno³, Soleh Wahyudi⁴

¹Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung, Indonesia.
²Department of Chemistry, Faculty of Mathematic and Natural Sciences, Halu Oleo University, Kendari, Indonesia.
³Mineral and Metallurgical Engineering Specialization, Postgraduate Program of Mining Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung, Indonesia.
⁴PT. Rekayasa Plating, Cimahi, Jawa Barat, Indonesia.

DOI: 10.4236/jmmce.2015.33018                

Abstract

2024 T3 is one of aluminium alloys which are widely used in the aircraft structures. Anodizing of alluminium alloy in tartaric-sulphuric acid (TSA) electrolyte is developed to obtain more environmentally-friendly process and to produce anodize layer with better corrosion resistance. In this research work, the influences of anodizing parameters of Al 2024 T3 in TSA on the thickness, weight and corrosion resistance of the anodize layer are studied. Corrosion resistance test was carried out by conducting salt spray test for 336 hours and anodic polarization measurements using potentiostat. Results of three-factor analysis of variance (ANOVA) demonstrated that the most influencing factor that determines the thickness and weight of the anodize layer is temperature, followed by applied voltage, duration of anodizing, voltage-temperature interaction, interaction of temperature-duration of anodizing, interaction of voltage-temperature-duration of anodizing, and interaction of voltage and duration of anodizing. The pit density and corrosion current density (i_corr) were found to be dependent on the coating thickness. The anodize layer with a thickness of higher than 3 μm was not experienced to pitting corrosion during 336 hours of salt spray test.

Keywords

Aluminium Alloy, Anodizing, TSA, Corrosion, Polarisation, Pitting

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Rubio, M.G., et al. (2009) Influence of Molybdate Species on the Tartaric Acid/Sulphuric Acid Anodic Films Grown on AA2024 T3 Aerospace Alloy. Corrosion Science, 51, 2034-2042. http://dx.doi.org/10.1016/j.corsci.2009.05.034
[2]	Capelossi, V.R., Poelman, M., Hernandez, R.P.B., Melo, H.G.D. and Olivier, M.G. (2014) Corrosion Protection of Clad 2024 Aluminum Alloy Anodized in Tartaric-Sulfuric Acid Bath and Protected with Hybrid Sol-Gel Coating. Electrochimica Acta, 124, 60-79. http://dx.doi.org/10.1016/j.electacta.2013.09.004
[3]	Rubio, M.G., et al. (2009) Effect of Postreatment on the Corrosion Behaviour of Tartaric-Sulphuric Anodic Films. Electrochimica Acta, 54, 4789-4800. http://dx.doi.org/10.1016/j.electacta.2009.03.083
[4]	Harscoet, E. and Froelich, D. (2008) Use of LCA to Evaluate the Environmental Benefits of Substituting Chromic Acid Anodizing (CAA). Journal of Cleaner Production, 16, 1294-1305. http://dx.doi.org/10.1016/j.jclepro.2007.06.010
[5]	Zhang, J., Zhao, X., Zuo, Y. and Xiong, J. (2008) The Bonding Strength and Corrosion Resistance of Aluminum Alloy by Anodizing Treatment in a Phosphoric Acid Modified Boric Acid/Sulfuric Acid Bath. Surface & Coating Technology, 202, 3149-3156. http://dx.doi.org/10.1016/j.surfcoat.2007.10.041
[6]	Boisier, G., Pébère, N., Druez, C., Villatte, M. and Suel, S. (2008) FESEM and EIS Study of Sealed AA2024 T3 Anodized in Sulfuric Acid Electrolytes: Influence of Tartaric Acid. Journal of the Electrochemical Society (JES), 155, 521-529. http://dx.doi.org/10.1149/1.2969277
[7]	Curioni, M., Skeldon, P., Koroleva, E., Thompson, G.E. and Ferguson, J. (2009) Role of Tartaric Acid on the Anodizing and Corrosion Behavior of AA 2024 T3 Aluminum Alloy. Journal of the Electrochemical Society (JES), 156, 147-153. http://dx.doi.org/10.1149/1.3077602
[8]	Theohari, S. and Kontogeorgou, C. (2013) Effect of Temperature on the Anodizing Process of Aluminum Alloy AA 5052. Applied Surface Science, 284, 611-618. http://dx.doi.org/10.1016/j.apsusc.2013.07.141
[9]	Sabry, R.S. and Alobaid, R. (2012) Effect of Preparation Conditions on Anodic Aluminium Oxide (AAO) Shape’s and Size. International Journal of Science and Research (IJSR), 3, 866-872.
[10]	Aerts, T., Jorcin, J.B., Graeve, D.I. and Terryn, H. (2010) Comparison between the Influence of Applied Electrode and Electrolyte Temperatures on Porous Anodizing of Aluminium. Electrochimica Acta, 55, 3957-3965. http://dx.doi.org/10.1016/j.electacta.2010.02.044
[11]	Aerts, T., De Graeve, I. and Terryn, H. (2008) Study of Initiation and Development of Local Burning Phenomena during Anodizing of Aluminium under Controlled Convection. Electrochimica Acta, 54, 270-279. http://dx.doi.org/10.1016/j.electacta.2008.08.004