Pitting corrosion meter

A pitting corrosion meter comprising:

• one or two test electrodes, a reference electrode and an auxiliary electrode, said electrodes being adapted for immersion in a corrodant fluid;
• circuit means for cathodically polarizing a said test electrode away from its rest potential to a predetermined negative potential with respect to said reference electrode and holding said test electrode at said predetermined potential for a predetermined period of time;
• circuit means for reading and storing the value of the resulting current between said test and auxiliary electrodes, said value corresponding to a point on a semilogarithmic cathodic polarization curve
• circuit means for generating said cathodic polarization curve and its extrapolation from one said reading and from stored information as to the slope of said curve or from two said readings at different predetermined negative potentials or from potentiodynamic cathodic polarization;
• circuit means for increasing the current or potential between a said test and auxiliary electrode at a fixed rate to a predetermined value in order to anodically polarize said test electrode with respect to said reference electrode, then decreasing the current or potential at a fixed rate;
• the values of the anodic current at their respective potentials corresponding to a forward anodic polarization curve and a reverse anodic polarization curve;
• circuit means for determining the intersection of said reverse anodic polarization curve with said cathodic polarization curve or its extrapolation by monitoring the individual values of the decreasing anodic current and their respective potentials, the value of the current at said intersection being that of the pitting current;
• and
• means for displaying and/or recording said pitting current, said pitting current being proportional to the pitting rate.