| Abstract: | A comprehensive presentation of the theory of galvanostatic anodization has been given in order to enable interpretation and prediction of the anodization behaviour of barrier layers during technical work on various value metals. The following parameters have been considered, and the relations between them have been established: - (i) oxide formation rate,
- (ii) reciprocal capacity,
- (iii) electric field strength,
- (iv) pre-polarization oxide thickness,
- (v) interfacial potentials,
- (vi) the height and width of energy barrier for ion transport in the oxide phase,
- (vi) the oxide growth rate as derived from the dependence of cd on time under constant potential, and
- (vii) capacity.
Furthermore, it has been demonstrated that potentiostatic curves can be derived from galvanostatic results, and the derived curves are similar to those directly measured by the potentiostatic technique. The theory has been satisfactorily applied to the experimental results based on the anodic charging curves and other complementary measurements on a large number of valve metals including Nb, Ta, Zr, Ti, Al, W, Te, Sb, and Bi. |
