Mohsen saket bejandi - MSc Student, School of Metallurgy and Materials Engineering
Changiz Dehghanian - Full professor, School of Metallurgy and Materials Engineering,School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran.

ceramic coatings are fabricated on pure aluminum by plasma electrolytic oxidation (PEO)in four kinds of electrolyte systems[phosphate-phosphat/silicate(2g/l)-phosphate-silicate(8g/l)-silicate].Effect of silicate concentrations on nanostructure and corrosion performance of PEO coatings were examined by means of scanning electron microscopy , x-ray diffraction, potentiodynamic polarization in 3.5% NaCl solution. The results showed that PEO films obtained in solutions with 8g/l silicate had better corrosion resistance. Phosphate/silicate (8g/l) electrolyte in comparison to phosphate, silicate and phosphate/silicate (2g/l), had lower porosity and cracks. Corrosion resistance of phosphate/silicate (8 g/l) electrolyte was higher than other electrolytes

PEO, oxide coatings, corrosion resistance, potentiodynamic polarization