INFLUENCE OF THE ELECTROCHEMICAL POTENTIA L DISTRIBUTION ON THE INTERPRETATION OF THE ANODIC CURRENT-VOLTAGE CURVE OF A ROTATING ELECTRODE OF A FE-31-PERCENT-NI ALLOY IN NORMAL SULFURIC-ACID-SOLUTION

The anodic steady-state polarization curve of a Fe-31 % Ni rotating-ri ng electrode in normal sulfuric acid was studied, and the dissolution profiles obtained ar different points of the curve were surveyed. We s howed chat the use of a rotating-ring elect-rode allowed to ob rain th e entire J(E) relationship between the current density J and the elect rochemical potential E, whereas this relationship cannot be obtained f rom the polarization curve of the classical rotating-disk electrode be cause of the non-uniform potential distribution over the disk surface. With the ring electrode, additional information on the transitions be tween three different states of the metal (homogeneous dissolution, in tergranular dissolution and passivity) could be obtained. (C) Academie des Sciences/Elsevier, Paris.