Electrical breakdown during anodic film formation on bismuth

Abstract

Studies are reported of the electrical breakdowns during galvanostatic anodization of Bi in electrolytes which are known to dissolve negligibly the anodic Bi 2O 3. The breakdown voltage U B proved to vary over a wide range (from 30 V to 400 V approximately) and to be mainly determined by the electrolyte resistivity ρ and composition. The temperature T and the current density have a comparatively small effect on U B. The expressions found for the dependences U B(ρ) and U B( T) agree in form with the corresponding equations in the theory of electrical breakdown during formation of barrier anodic films. The constants in these equations are evaluated, which enables the selection of the electrolyte and the anodizing conditions for achieving a desired potential drop across the anodic film to be made.