FORMATION OF BARRIER OXIDE FILM ON LEAD IN BORATE SOLUTIONS

Galvanostatic anodization of lead in borate solutions reveals that lea d can form a barrier type oxide film. The rate of growth, R, fulfils t he empirical relation, R = ai(b) within the current density i range fr om 1.16 . 10(-4) to 3.19 . 10(-4) A cm-2. The magnitudes of the parame ters a and b are 6.9 . 10(3) and 1.6, respectively, it has been found that the high field approximation is applicable for the oxide growth o n lead. The coefficients of the dependence of R on solution temperatur e, T, pH and borate ion concentration, c, viz. (partial derivative R/p artial derivative T), (partial derivative R/partial derivative pH) and (partial derivative R/partial derivative log c) are -18 . 10(-4), -0. 13 and 0.41, respectively.