Temperature dependence of the anodic oxidation of titanium below the oxygen evolution potential

The growth of thin anodic oxide films on Ti in the temperature range between 20 and 70° C can be expressed in purely coulometric terms. In diluted and aerated borate solutions the potential increases linearly with time; the slope of the curves increases with increasing current intensity; after 10 to 20 min all the curves show a transition to a flattened shape. Temperature changes have but an insignificant influence on the general character of the curves; the transition to the flatter portion occurs after about 20 min, too, but potentials are the lower, the higher the temperature. The values of the activation energy calculated from the results show, that the layer formation is not only controlled by the bound are face reactions, but also by certain factors coming from the bulk of the solution.