Influence of process parameters on growth behaviour and properties of coatings obtained by plasma electrolytic oxidation (PEO) on AA 6061
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Plasma electrolytic oxidation coating is obtained on AA6061 alloy using positive uni-polar pulsed DC in a sodium silicate-based electrolyte. The effect of process parameters such as solution concentration, process time, average current density, pulse frequency and positive on-time is investigated systematically and the corresponding voltage–time response is correlated with the coating growth rate. Surface morphology of the coatings is studied using scanning electron microscopy and the elemental distribution on the coating is investigated using energy dispersive X-ray spectroscopy. The concentration of sodium silicate in the solution is found to play a key role in determining the morphology and composition of the coating. X-ray diffraction studies indicate a transition from crystalline to amorphous nature of the coating with increase in silicate content of the electrolyte. Effect of pulse frequency on the voltage–time response and the corresponding coating growth rate is highly dependent on the solution concentration.
KeywordsPlasma electrolytic oxidation (PEO) Aluminium alloys Surface morphology Elemental distribution studies XRD
The authors wish to express their sincere gratitude to Prof. S. Sampath, Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore for his valuable guidance and technical assistance in conducting this research work.
- 4.Zhang Y, Fan W, Du HQ, Zhao YW (2017) Plasma electrolytic oxidation coatings for aluminum alloys. Mater Perform 56(9):38–41Google Scholar
- 12.Liu YJ, Xu JY, Lin W, Gao C, Zhang JC, Chen XH (2013) Effects of different electrolyte systems on the formation of micro-arc oxidation ceramic coatings of 6061 aluminum alloy. Rev Adv Mater Sci 33:126–130Google Scholar
- 25.Peters M, Leyens C (2009) Aerospace and space materials, materials science and engineering—vol. III. EOLSS PublicationsGoogle Scholar
- 26.Wernick S, Pinner R, Sheasby PG (1987) The surface treatment and finishing of aluminium and its alloys—vol 1, 5th edn. ASM InternationalGoogle Scholar
- 28.Zhang Y, Fan W, Du HQ, Zhao YW (2018) Formation of corrosion-resistant MAO-treated aluminum alloy. Mater Perform 57(2):36–39Google Scholar
- 30.Dehnavi V, Surface modification of aluminum alloys by plasma electrolytic oxidation, Thesis from The University of Western Ontario, Canada, September 2014Google Scholar