Abstract
It has already been advanced by various investigators and also by the authors that the potentiokinetic measuring techniques can lead to erroneous conclusions. This is also true for the determination of the pitting potential. To avoid the disadvantages of the potentiokinetic method, a new procedure has been worked out: the static potential band method. Using the electrical resistance of a tested metal specimen, a potential drop is realized over the specimen by means of an external direct current, chosen in such a way that the pitting potential lies within the potential drop along the specimen. The absolute value of the potential is controlled by means of a potentiostat. By applying this method, the limit at which pitting does or does not appear can be visually or microscopically determined. At the same time information can be obtained about the distribution of the pits as a function of the potential. From this, a distribution curve can be drawn by which the average number of pits per potential interval can be shown. This method can also be used for drawing experimental immunity-corrosion-passivation diagrams, for research on inhibitors and for the examination of stress corrosion. This principle can also rather easily be applied to high temperature experiments.
