Determination of the morphology factor of oxide layers

From the linear dependencies of the voltammetric capacitive current, i(c), with the potential sweep rates, nu, observed in the low and high domains, i t is possible to determine the inner and outer differential capacities of o xide coatings. The morphological factor,phi, defined as the ratio of the in ner and total differential capacities (C-d,C-i/Cd) shows a linear relations hip with the radius/ionic charge ratio of the anion of the supporting elect rolyte. The dependence of the capacitive voltammetric charge, q(c), on nu w as interpreted on the basis of a purely capacitive model for the oxide/solu tion interface. (C) 2001 Elsevier Science Ltd. All rights reserved.