Effect of Negative Pulse Voltage on the Microstructure and Corrosion Resistance of Microarc Oxidation Film of A356 Aluminum Alloy

Abstract:

The effect of negative pulse voltage on the microstructure and corrosion resistance of microarc oxidation film of A356 aluminum alloy treated by microarc technique was investigated by SEM, coating thickness gauge and electrochemical workstation etc. The results show the negative pulse voltage greatly influences the microstructure and corrosion resistance of microarc oxidation film by its electrode reaction. The film thickness increases while the size of pore and roughness of the film surface decreases initially and then increases with negative pulse voltage increasing. The microarc oxidation treatment considerably improved corrosion resistance, and the highest corrosion potential was -1.16V, which was 0.38V higher than that of substrate, and the corrosion current was lower than that of substrate about three orders of magnitude.

• Periodical: Materials Science Forum (Volumes 675-677)
• Pages: 1193-1196
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.675-677.1193
• Online since: February 2011
• Authors: Guang Huai Peng, Bao Jun Han, Ling Fang, Xue Feng Guo, Xiao Lian Zhang
• Keywords: Corrosion Resistance, Micro-Arc Oxidation (MAO), Microstructure, Negative Pulse Voltage

References

[1] E. S. Atroshchenko, O. E. Chufistove, I. A. Kazantsev. Formation of structure and properties of coatings deposited by microarc oxidizing on parts fabricated from aluminum alloys[J]. Metal Science and Heat Treatment Vol. 42(10) (2000), pp.411-415.

DOI: 10.1007/bf02725327

[2] H.F. Guo, M.Z. An, S. Xu, et al. Microarc oxidation of corrosion resistant ceramic coating on a magnesium alloy [J]. Materials Letters Vol. 60(12) (2006), pp.1538-1541.

DOI: 10.1016/j.matlet.2005.11.066

[3] T.B. Wei, F.Y. Yan, J. Tian. Characterization and wear and corrosion resistance of microarc oxidation ceramic coatings on aluminum alloy [J]. Journal of Alloys and Compounds Vol. 389(1-2) (2005), pp.169-176.

DOI: 10.1016/j.jallcom.2004.05.084

[4] H.F. Guo, M.Z. An, S. Xu, et al. Microarc oxidation of corrosion resistant ceramic coating on a magnesium alloy[J]. Materials Letters Vol. 60(12) (2006), pp.1538-1541.

DOI: 10.1016/j.matlet.2005.11.066

[5] Y. Q. Wang, K. Wu, M. Y. Zheng. Effects of reinforcement phases in magnesium matrix composites on microarc discharge behavior and characteristics of microarc oxidation coatings[J]. Surface and Coatings Technology Vol. 201(1-2) (2006), pp.353-360.

DOI: 10.1016/j.surfcoat.2005.11.129

[6] H.H. Wu , X.Y. Lu , B.H. Long , et al. The effects of cathodic and anodic voltages on the characteristics of porous nanocrystalline titania coatings fabricated by microarc oxidation[J]. Materials Letters Vol. 59(2-3) (2005), pp.370-375.

DOI: 10.1016/j.matlet.2004.10.019

[7] R.M. Liu,　F. Guo, P.F. Li. Effect of voltage on formation of ceramic coating preparedby micro-arc oxidation on aluminum alloy (in chinese) [J]. Transactions of materials and heattreatment Vol. 29(1) (2008), pp.137-140.

[8] A. L. Yerokhin, V. V. Viktor, L. V. Ashitkov, et al. Phase formation in ceramic coatings during plasma electrolytic oxidation of aluminum alloys[J]. Ceramic International Vol. 24(1) (1998), pp.1-6.

DOI: 10.1016/s0272-8842(96)00067-3