Effect of Frequency and Duty Cycle on Growth, Structure and Corrosion Resistance of Micro Arc Oxidation Coating on RZ5 Magnesium Alloy

Abstract:

Magnesium alloys inherently possess poor corrosion resistance. One of the surface modification techniques to improve the corrosion resistance of magnesium alloys is Micro Arc Oxidation (MAO). Application of RZ5 magnesium alloy in aircraft industries demands assured corrosion resistance of RZ5. The quality of the ceramic oxide coating developed by MAO is influenced by various operating parameters. In this study, oxide coatings on RZ5 Magnesium alloy were developed by MAO at two different frequency levels (100Hz and 1000Hz) and at two duty cycles (10% and 90%) at a constant current density of 0.06A/cm² for 15 minutes in a silicate based electrolyte (10g/l Na₂SiO₃.9H₂O + 4g/l KOH). Results showed that the coating produced with the combination of higher frequency and lower duty cycle exhibits a better corrosion resistance than the coating produced with other combinations of parameters.

• Periodical: Key Engineering Materials (Volume 775)
• Pages: 291-297
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.775.291
• Online since: August 2018
• Authors: V. Ram Kumar, V. Muthupandi*, Katakam Sivaprasad, P. Bala Srinivasan
• Keywords: Corrosion, Magnesium Alloy, Micro Arc Oxidation

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