抄録
The linear polarization method is useful for corrosion monitoring in the case of the application to the limited area of specimen in laboratories or in plants. It is, however, not used to monitor the localized corrosion in operating apparatus because of the indefiniteness of the area to be monitored. In order to determine the configuration and setting of the probe for monitoring corrosion, which has the counter electrode in it to polarize the objective, Laplace's equations which describe the electrostatic potential distribution in the system to measure the polarization resistance are solved. The stream lines of the applied current are also calculated. In case of general corrosion, five parameters such as conductivity of the solution, polarization resistance, radius of the probe, distance of the probe from the surface monitored, and the horizontal level of the soultion surface above the metal surface are introduced. In case there exists an anodic pit, parameters which describe the polarization resistances of the anodic site and cathodic area and the radius of the pit are also introduced. Relations between the experimentally obtained polarization resistance and the “true” polarization resistance, which reflects the corrosion rate, are graphically shown.
