“…The very low stripping rate of the composite oxide barrier film may be due to the presence of v-alumina, which, when produced by thermal oxidation, has been observed to be only very slowly dissolved, if at all, by the stripping solution (11). Jackson and Waddell (12) have reported that the surface of the barrier film of a composite oxide formed in a boric acid electrolyte is ~-AlsO3, with a small amount of amorphous oxide distributed in the crystalline oxide.…”