Chronoamperometric Evaluation of Sensitization of SUS 316 Stainless Steel

The extent of sensitization of austenitic stainless steel, SUS316, was evaluated by both conventional cyclic voltammetry and potential step chronoamperometry (PSCA). The test solution used for the test was 0.511" 3 284 -0.0111" 3 potassium thiocyanate solution. First, the ratio of peak currents in cathodic and anodic scanning (reactivation ratio) using the Electrochemical Potentiokinetic Reactivation method (EPR) based on conventional cyclic voltammetry was measured. Second, the modification reactivation ratio by PSCA was measured and both data were compared and discussed to determine the extent of sensitization. The modified reactivation ratio had a better correlation with sensitization time than the conventional reactivation ratio. However, the correlation ratio was not so high as a whole for SUS316. The reason for this could be attributable to the complication involved in the anodic reaction.