Corrosion-Resistance of MAO-Coatings on Al-Si Alloys

Abstract:

The results of the experimental study of the influence of micro-arc oxidation (MAO) on the corrosion resistance of aluminum alloy samples AK12D are presented in this paper. The description of the research methodology, including the formation of the hardened layer on the surface of laboratory samples by MAO under various process conditions and the study of their corrosion resistance are given. The studies were conducted in accordance with the experimental design theory for fractional factorial experiment 2^3-1. The MAO process was carried out using an alkaline electrolyte. MDO process factors were chosen according to an electrolyte concentration of the components (caustic potash - KOH and water glass - Na2SiO3) and electrical parameters of the process determined by the capacitors capacitance. In addition to corrosion resistance of the samples, the thickness, porosity, and microhardness of MAO layer were determined. Regression equations and conclusions about the degree of influence of modes of micro-arc oxidation on the corrosion resistance of the samples were compiled on the basis of the data obtained. The results showed that the MAO process regimes have a significant effect on the corrosion resistance of the samples. Regression equations describing the effect of the thickness and porosity of the surface on the corrosion rate are derived. It has been found that the greatest influence on the corrosion resistance renders the mean value of porosity. With an increase of this parameter there is an increase in the corrosion resistance of the coating. To account for this effect, it has been suggested that the corrosion resistance of the MAO layer should not correlate with the porosity but with the absolute volume occupied by the pores in the coating. The study was conducted to investigate the prospects for the use of the MAO method for improving the corrosion properties of parts and details made of Al-Si aluminum alloys.

• Periodical: Materials Science Forum (Volume 870)
• Pages: 83-89
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.870.83
• Online since: September 2016
• Authors: N.Yu. Dudareva*, Marina M. Abramova, R.V. Kalschikov
• Keywords: Aluminum Alloys, Corrosive Behavior, Micro Hardness, Microarc Oxidation

References

[1] R. Cobden, Alkan, Banbury, Aluminium: Physical Properties, Characteristics and Alloys, TALAT Lecture 1501, EAA - European Aluminium Association, (1994).

[2] K. Dudzik, Mechanical properties of 5083, 5059 and 7020 aluminium alloys and their joints welded by MIG, J. of KONES Powertrain and Transport. 18 (2011) 73-77.

DOI: 10.5604/12314005.1137318

[3] B.R. Spacht, The corrosion resistance of aluminum and its alloys, J. Chem. Educ. 23 (1946) 253.

[4] J.R. Davis, Corrosion of Aluminum and Aluminum Alloys, ASM International, (1999).

[5] B.E. Placzankis, General Corrosion Resistance Comparisons of Medium-and High-Strength Aluminum Alloys for DOD Systems Using Laboratory-Based Accelerated Corrosion Methods, Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5066, (2009).

DOI: 10.21236/ada516812

[6] Aliminium and Corrosion, UK Aluminium Industry, Fact Sheet 2, (2014).

[7] J. Yue, Y. Cao, Corrosion Prevention by Applied Coatings on Aluminum Alloys in Corrosive Environments, Int. J. Electrochem. Sci. 10 (2015) 5222-5237.

DOI: 10.1016/s1452-3981(23)17250-6

[8] A.Y. Musa, Corrosion Protection of Al Alloys: Organic Coatings and Inhibitors, Recent Researches in Corrosion Evaluation and Protection, Materials Science: Biomaterials. (2012) 51-66.

DOI: 10.5772/31983

[9] S.V. Oleinik, Yu. I. Kuznetsov, Corrosion Inhibitors in Conversion Coatings, IV, J. Protection of Metals. 43 (2007) 391-397.

DOI: 10.1134/s0033173207040133

[10] A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews, S.J. Dowey, Plasma electrolysis for surface engineering, J. Surface and Coatings Technology. 122 (1999) 73-93.

DOI: 10.1016/s0257-8972(99)00441-7

[11] R.H.U. Khan, A. Yerokhin, A. Matthews, X. Li, H. Dong, Surface characterization of dc plasma electrolytic oxidation treated 6082 aluminium alloy effect of current density and electrolyte concentration, J. Surface and Coatings Technology. 205 (2010).

DOI: 10.1016/j.surfcoat.2010.04.052

[12] H.X. Li, V.S. Rudnev, X.H. Zheng, T.P. Yarovaya, R.G. Song, Characterization of Al2O3 ceramic coatings on 6063 aluminium alloy prepared in borate electrolytes by micro arc oxidation, J. Journal of Alloys and Compounds. 462 (2008) 99-102.

DOI: 10.1016/j.jallcom.2007.08.046

[13] O. Young-Jun, M. Jung-II, K. Jung-Hwan, Effects of alloying elements on microstructure and protective properties of Al2O3 coatings formed on aluminium alloy substrates by plasma electrolysis, J. Surf & Coat Technol. 204 (2009) 141-148.

DOI: 10.1016/j.surfcoat.2009.07.002

[14] K. Tillous, T. Toll-Douchanoy, E. Bauer-Grosse, L. Hericher, G. Geandier, Microstructure and phase composition of micro arc oxidation surface layers formed on aluminium and its alloys 2214-T6 and 7050-T74, J. Surf. & Coat. Technol. 203 (2009).

DOI: 10.1016/j.surfcoat.2009.03.021

[15] E.S. Atroshchenko, O. E. Chufistov, I. A. Kazantsev, S. I. Kamyshanskii, Formation of structure and properties of coatings deposited by microarc oxidizing on parts fabricated from aluminum alloys, J. Metal Science and Heat Treatment. 42 (2000).

DOI: 10.1007/bf02725327

[16] B. Rajasekaran, S. Ganesh Sundara Raman, L. Rama Krishna, S.V. Joshi, G. Sundararajan, Influence of micro arc oxidation and hard anodizing on plain fatigue and fretting fatigue behaviour of Al−Mg−Si alloy, J. Surf & Coat Technol. 202 (2008).

DOI: 10.1016/j.surfcoat.2007.06.058

[17] K. Prasad Rao, G.D. Janaki Ram, B.E. Stucker, Improvement in corrosion resistance of friction stir welded aluminium alloys with micro arc oxidation coatings, J. Scripta Materialia. 58 (2008) 998-1001.

DOI: 10.1016/j.scriptamat.2008.01.033

[18] X. Wen-bin, W. Chao, T. Hua, L. Yong-chun, Corrosion behaviours and galvanic studies of micro arc oxidation films on Al-Zn-Mg-Cu alloys, J. Surf & Coat Technol. 201 (2007) 8695-8701.

DOI: 10.1016/j.surfcoat.2006.10.029

[19] D.T. Asquith, A.L. Yerokhin, J.R. Yates, A. Matthews, The effect of combined shot-peening and PEO treatment on the corrosion performance of 2024 aluminium alloy, J. ThinSolid Films. 516 (2007) 417-421.

DOI: 10.1016/j.tsf.2007.06.166

[20] M.M. Krishtal, Effect of Structure of Aluminum-Silicon Alloys on the Process of Formation and Characteristics of Oxide Layer in Microarc Oxidizing, J. Metal Science and Heat Treatment. 46 (2004) 377-384.

DOI: 10.1023/b:msat.0000049810.75325.f9

[21] S.К. Kiselyeva, L.I. Zaynullina, М.М. Abramova, N.Y. Dudareva, I.V. Alexandrov, The Effect of Microarc Oxidation (MAO) Modes on Corrosion Behavior of High-Silicon Aluminum Alloy, Journal of Engineering Science and Technology Review. 7 (2014).

DOI: 10.25103/jestr.075.10

[22] Information on http: /www. splav-kharkov. com.

[23] Iu.P. Adler, Planning of Experiment with Finding the Optimal Conditions, Moscow, Nauka. (1976).

[24] T. Wei, Characterization and wear- and corrosion-resistance of microarc oxidation ceramic coatings on aluminum alloy, J. Journal of Alloys and Compounds. 389 (2005) 169-176.

DOI: 10.1016/j.jallcom.2004.05.084