Comparison of Electrochemical and Chemical Corrosion Behavior of MRI 230D Magnesium Alloy with and without Plasma Electrolytic Oxidation Treatment

Abstract:

Magnesium is one of the lightest metals and magnesium alloys have quite special properties, interest to which is continuously growing. In particular, their high strength-to-weight ratio makes magnesium alloys attractive for various applications, such as transportation, aerospace industry etc. However, magnesium alloys are still not as popular as aluminum alloys, and a major issue is their corrosion behavior.The present research investigated the influence of the PEO treatment on the corrosion behavior of MRI 230M magnesium alloy. Plasma electrolytic oxidation (PEO) of an MRI 230M alloy was accomplished in a silicate-base electrolyte with KF addition using an AC power source.The corrosion behavior of both treated and untreated samples was evaluated by open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear polarization tests, linear sweep voltammetry (Tafel extrapolation) and chemical methods, such as mass loss and hydrogen evolution, in neutral 3.0 wt% NaCl solution.According to the tests results, PEO process can affect the corrosion resistance of MRI 230M magnesium alloy, though its action is not always unambiguous. An attempt to explain the influence of the PEO treatment on the corrosion behavior of the alloy is presented.

• Periodical: Defect and Diffusion Forum (Volume 364)
• Pages: 27-34
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.364.27
• Online since: June 2015
• Authors: Barbara Kazanski*, Alex Lugovskoy, Ohad Gaon, Michael Zinigrad
• Keywords: Impedance Spectroscopy, Linear Polarization Resistance, Magnesium Alloys, Plasma Electrolytic Oxidation, Tafel Polarization, Weight Loss

References

[1] B.L. Mordike, T. Ebert, Magnesium: Properties, applications, potential, Mater. Sci. Eng., A302, 37–45, (2001).

[2] B. A. Shaw, Corrosion Resistanceof Magnesium Alloys, ASM Handbook, 13A, 692-695, (2003).

[3] A. L. Rudd, C. B. Breslin, F. Mansfeld, The corrosion protection afforded by rareearth conversion coatings applied tomagnesium, Corros. Sci., 42, 275-288, (2000).

DOI: 10.1016/s0010-938x(99)00076-1

[4] S. Shadanbaz, G. J. Dias, Calcium phosphate coatings on magnesium alloys for biomedical applications: A review, Acta Biomaterialia, 8, 20–30, (2012).

DOI: 10.1016/j.actbio.2011.10.016

[5] C.E. Barchiche, E. Rocca, C. Juers, J. Hazan, J. Steinmetz, Corrosion resistance of plasma-anodized AZ91D magnesiumalloy by electrochemical methods, Electrochim. Acta, 53, 417–425, (2007).

DOI: 10.1016/j.electacta.2007.04.030

[6] R.G. Hu, S. Zhang, J.F. Bu, Ch.J. Lin, G.L. Song, Recent progress in corrosion protection of magnesium alloys by organic coatings, Prog. Org. Coat., 73, 129– 141, (2012).

DOI: 10.1016/j.porgcoat.2011.10.011

[7] K. Murakami, M. Hino, K. Nakai, S. Kobayashi,A. Saijo, T. Kanadani, Mechanism of Corrosion Protection of Anodized Magnesium Alloys, Mater. Transact., 49 (5), 1057–1064, (2008).

DOI: 10.2320/matertrans.mc200718

[8] B. Kazanski, A. Kossenko, M. Zinigrad, A. Lugovskoy, Fluoride ions as modifiers of the oxide layer produced by plasma electrolytic oxidation on AZ91D magnesium alloy, App. Surf. Sci., 287, 461– 466, (2013).

DOI: 10.1016/j.apsusc.2013.09.180

[9] J. Li, Y. Tian, Z. Cui, Z. Huang, Effects of rare earths on the microarc oxidation of a magnesium alloy, Rare Metals, 27 (I), 50– 54, (2008).

DOI: 10.1016/s1001-0521(08)60029-7

[10] H. Duan, C. Yan, F. Wang, Effect of electrolyte additives on performance of plasma electrolyticoxidation films formed on magnesium alloy AZ91D, Electrochim. Acta, 52, 3785–3793, (2007).

DOI: 10.1016/j.electacta.2006.10.066

[11] R.F. Zhang, D.Y. Shan, R.S. Chen, E.H. Han, Effects of electric parameters on properties of anodic coatings formed on magnesium alloys, Mater. Chem. and Phys., 107, 356–363, (2008).

DOI: 10.1016/j.matchemphys.2007.07.027

[12] C. Blawert, V. Heitmann, W. Dietzel, H.M. Nykyforchyn, M.D. Klapkiv, Influence of process parameters on the corrosion properties of electrolyticconversion plasma coated magnesium alloys, Surf. Coat. Tech., 200, 68– 72, (2005).

DOI: 10.1016/j.surfcoat.2005.02.035

[13] E. Cakmak, K. C. Tekin, U. Malayoglu, S. Shrestha, The effect of substrate composition on the electrochemical and mechanicalproperties of PEO coatings on Mg alloys, Surf. Coat. Tech., 204, 1305–1313, (2010).

DOI: 10.1016/j.surfcoat.2009.10.012

[14] R. Arrabal, E. Matykina, F. Viejo, P. Skeldon, G.E. Thompson, Corrosion resistance of WE43 and AZ91D magnesium alloys with phosphate PEO coatings, Corros. Sci., 50, 1744–1752, (2008).

DOI: 10.1016/j.corsci.2008.03.002

[15] X. Zeng, Y. Wang, W. Ding, A. A. Luo,A. K. Sachdev, Effect of Strontium on the Microstructure, MechanicalProperties, and Fracture Behavior of AZ31 Magnesium Alloy, Metal. Mater. Trans., 37A, 1333–1341, (2006).

DOI: 10.1007/s11661-006-1085-8

[16] Z. Shi, M. Liu, A. Atrens, Measurement of the corrosion rate of magnesium alloys using Tafel extrapolation, Corros. Sci., 52, 579–588, (2010).

DOI: 10.1016/j.corsci.2009.10.016

[17] F. Cao, Z. Shi, J. Hofstetter, P. J. Uggowitzer, G. Song, M. Liu, A. Atrens, Corrosion of ultra-high-purity Mg in 3. 5% NaCl solution saturated with Mg(OH)2, Corros. Sci., 75, 78–99, (2013).

DOI: 10.1016/j.corsci.2013.05.018

[18] E. Aghion, B. Bronfin, F. von Buch, S. Schumann, H. Friedrich, The art of developing new magnesium alloys for high temperature applications, Mater. Sci. Forum, 419, 407-418, (2003).

DOI: 10.4028/www.scientific.net/msf.419-422.407