Effect of Urea on The Microstructure and Corrosion Resistance of Plasma Electrolyte Oxidation Coating Applied on Al 1050

In this study, plasma electrolyte oxidation (PEO) coating was applied on the aluminum sheets in an alkaline electrolyte solution with different amount of urea (10,100 g/l) and different time period (10,20 min) and in two level of current density (30,100 mA/cm2). SEM analysis was used to study surface structure and cross-section of prepared coatings. Also, anti-corrosion properties of coatings were investigated by electrochemical impedance spectroscopy (EIS). SEM analysis from top surfaces showed that the coatings formed in the electrolyte containing 100 g/l urea, are more uniform and have fine pores, while the coatings formed in the electrolyte containing 10 g/l urea have coarse structure with larger pores. EIS results showed that the impedance modulus of coatings containing 100 gr/l urea were almost 10 times higher than for coatings containing 10 g/l urea.