Issue 3(53) 2009
Pages 53-59


For the first time it was shown that under underground corrosion conditions the kinetics of anodic process of carbon steel is completely determined by properties of ground electrolyte formed in the thin layer at a metal surface. Tafel plot of the anodic polarization curve is placed at the same potentials as in electrolyte solution and its slope is equal to 40 mV. The repassivation potential determined by potentiodinamic method in electrolyte identical to the ground one is a reliable criterion of differentiation of potential areas of pitting corrosion (more positive) and its absence (more negative). To get the reliable polarization curves in grounds is possible only under the conditions that their specific electrical resistance does not exceed 1 Ohm m and the reference electrode is built-in into working electrode. Even in grounds with low specific electrical resistance the application of any standard reference electrodes (including Ag/AgCl) for maintenance and registration of potential results in distortion of results owing to presence of a IR-error dependent on metal potential.