Breakdown and Efficiency of Anodic Oxide Growth on Titanium

The breakdown voltage, as defined by low coulombic efficiency of film formation, increases as the rate of anodic oxide growth on Ti increases. Ellipsometric determination of film thickness shows that the field across the oxide is not constant despite constant ionic flux. Changes in the ionic conductivity of the oxide are proposed to explain the nonlinear voltage/time behavior, and a range of high ionic conductivity is found at high growth rates preceding breakdown and crystallization.