Corrosion Protection and Microstructure of Magnesium Alloys Anodized by Phosphate Solution

Abstract:

Corrosion protection by anodization and conversion treatment in phosphate solution was studied by microstructural and electrochemical analysis. Both the anodized and the conversion-treated layers showed sacrificial protection in a solution of sodium chloride. The corrosion current or the dissolving rate of the anodized layer was smaller than that of the conversion-treated surface. The modified layers had another mode of protection to form protective films on magnesium substrate where the original modified layers were mechanically lost. Since the state of magnesium in the anodized layer is close to magnesium oxide, phosphorus in the layer is considered to have an important role in these properties concerning the above corrosion protection.

• Periodical: Materials Science Forum (Volumes 638-642)
• Pages: 1464-1469
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.638-642.1464
• Online since: January 2010
• Authors: Koji Murakami, Makoto Hino, Atsushi Saijo, Teruto Kanadani
• Keywords: Anodization, Conversion Treatment, Magnesium Alloy, Microstructure, Phosphate Solution, Sacrificial Protection

References

[1] T.F. Barton: US-Patent 5792335 (1998).

[2] M. Hino, M. Hiramatsu, K. Murakami and T. Kanadani: J. Surf. Fin. Soc. Jpn., Vol. 54 (2003), p.542.

[3] A. Saijo, M. Hino, M. Hiramatsu, K. Murakami and T. Kanadani: J. Surf. Fin. Soc. Jpn., Vol. 56 (2005), p.63.

[4] M. Hino, M. Hiramatsu, K. Murakami, A Saijo and T. Kanadani: J. Jpn. Inst. Light Metals, Vol. 56 (2006), p.386.

[5] K. Murakami, M. Hino, M. Hiramatsu, K. Nakai, S. Kobayashi, A Saijo and T. Kanadani: Mater. Trans., Vol. 48 (2007), p.3101.

DOI: 10.2320/matertrans.l-mra2007881

[6] K. Murakami, M. Hiramatsu, M. Hino, K. Sueoka and R. Nakanishi: J. Surf. Fin. Soc. Jpn., Vol. 58 (2007), p.280.

[7] D. Hawke and D.L. Albright: Metal Fin., Vol. 93(10) (1995), p.34.