Development of anodic coating on aluminum by H3BO3/H2SO4 anodizing

In this study, anodic oxidation of aluminium was performed in aqueous solution containing both boric acid and sulphuric acid, on aluminium anode, by electrolysis. According to experimental datas, ideal anodizing potential value is 15 V chosen. At constant electrolysis potential , different anodizing times was performed (10, 15, 20, 25, 30, 60, 90, 120 minutes) on aluminium. A convenient anodizing time is 30 minute determined. Anodizing applied at room temperature (22 oC), 30, 40, 50oC. The appropriate corrosion performance seem in room temperature. After determinated convenient anodizing parameters the corrosion performance of Al / Al2O3 has been investigated in % 3.5 NaCl solution for 30 days. For this aim, electrochemical impedance spectroscopy was utilized. Also, the corrosion potentials (Ecor) and the inverse polarization resistance (Rp) are determined. These results proved that the oxide coating (Al2O3) obtained on aluminum surface exhibited important corrosion protection; the aluminium substrate could be successfully protected by this anodic protection. Key Words: Anodizing, aluminium, corrosion