2007 Volume 56 Issue 3 Pages 106-111
The pitting behavior of SUS 304 stainless steel was investigated first in FeCl3 solutions of various concentrations to follow the variation of corrosion potential. Typical fluctuations of corrosion potential were observed in relatively dilute solutions because of large polarization of the cathodic reaction. Secondly, the internal current was evaluated by coupling the anode (SUS 304 stainless steel in a Fe3+ free chloride solution) and the cathode (SUS 316 stainless steel in a FeCl3 solution). Then cathodic polarization characteristic on SUS 316 stainless steel was evaluated in FeCl3 solutions. The data was inputted into a computer and a program was made to control a potentiostat in order that the measured anodic current be always same as the inputted cathodic one at each potential in magnitude. Finally, SUS 304 stainless steel in a Fe3+ free chloride solution was anodically polarized by the potentiostat. All three kinds of tests gave common potential fluctuation patterns indicating the validity of the idea of “artificial cathode”.
