DETERMINATION OF PH DURING PERIODIC CATHODIC POLARIZATION OF ELECTRODES

The background to the investigation was the corrosion protection of rotating Fe cylinders by periodic cathodic polarization. To obtain a better understanding of the progress of the reaction, it was necessary to determine, in addition to the surface potential, the pH close to the metal surface during the cycle of the periodic polarization. Two methods of calculation of the changes in pH for idealized convection conditions are treated. A method to measure the changing pH close to a periodically polarized electrode is described, in which the disadvantage of the long reaction time of the pH measuring electrode has been overcome. There is good agreement between calculated and experimental results. © 1969.