Kinetics of formation of complex anodic oxide films on aluminium

The kinetics of formation of “complex” anodic films on aluminium obtained by an electrochemical filling the porous alumina films in an aqueous borate electrolytic solution has been investigated. Complex anodic oxide films with entirely or partially filled pores depending on the porous matrix thickness were obtained. The slopes of the kinetic curves (∂Uf/∂Qf) during a re-anodization as a function of the thickness of porous films formed in H2SO4 and (COOH)2 are presented. The electric field strength values through the filling porous films were calculated. Three types of equations were used to calculate the ionic current as a function of the electrical field strength. The values of two important kinetic characteristics of the filling process (the electrical charge passed for the whole filling the porous film, and the re-anodization voltage reached at the moment of an entire filling the film) were determined. The values of these characteristics are plotted vs. the thickness of porous alumina films.