Anodic oxide growths on commercially pure titanium in 1 M sulphuric and phosphoric acids have beeninvestigated in the present study. Ruptures and blisters of the oxide layers were found as result of ahuge pressure of oxygen bubbles developed within the film. The ruptures were more pronounced whenhigher anodic voltages are reached for both acid anodizations. The oxygen evolution was probablyinhibited more significantly for phosphoric acid anodization compared to sulphuric acid anodization.The anodic oxides also showed more ruptures after anodized titanium specimens were immersed for 60days in naturally aerated 3.5% NaCl electrolyte in higher anodic voltage compared to the immediately榡ustimmersed conditions in the NaCl electrolyte. The corrosion behaviours of the anodic oxides werestudied in the 3.5% NaCl by potentiodynamic polarization and electrochemical impedancespectroscopy. Increased corrosion resistance of the anodic oxides on titanium in NaCl were observedwith increase in anodic voltages. The anodic oxide produced in the phosphoric acid showed a highercorrosion resistance than that of the sulphuric acid at each anodizing condition; indicates that thecorrosion protection by anodizing for titanium in phosphoric acid should probably be considered inpriority compared with sulphuric acid.
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