Commercially pure titanium and the alloys studied exhibited active to passive transitions in . Increasing the acid concentration increased the critical current density for passivity and the dissolution current density in the passive range and shifted the critical potential for passivity in the noble direction. Increasing the temperature served only to increase the critical current density for passivity and the dissolution current density in the passive range. Activation energies for the anodic polarization process were the right order of magnitude for a reaction controlled by reactivity at the metal surface. For the α‐β alloy 6Al‐6V‐2Sn the critical current density for passivity increased as the ratio of amounts of beta to alpha phase decreased with increasing strength level. The dissolution is accelerated probably, by the galvanic effects and the unfavorable area ratio. Ti 75A, a commercially pure metal, had a smaller critical current density for passivity value than did the alloys, which was expected. Secondary current density increases were observed for all the alloys at potentials above + 1.0v. For the 13V‐11Cr‐3Al alloy such behavior was attributed to transpassivity. For the other alloys the phenomena was attributed to pitting or localized corrosion. The commercially pure metal remained passive in this potential range. The addition of Fe3+ and Cu2 + (0.03M) to the facilitated passivation of the metal and its alloys. Pitting of several of the alloys occurred in but not in .