Influence of test parameters of potentiodynamic current density measurements on the determination of the pitting corrosion resistance of austenitic stainless steels

Abstract

It is possible to determine the pitting corrosion resistance of a stainless steel in a given solution of a chemical process by electrochemical techniques. However, it is known that the result is influenced by the test parameters. The aim of this study was to determine the influence of the main test parameters, scan rate, imax; agitation/flow rate, and surface pretreatment on the electrochemical response of 316Ti/1.4571 stainless steel in an acidic (250 ppm Cl−, pH: 4, T: 30 °C) and an alkaline (4% Cl−, pH: 9, T: 80 °C) solution. The results were compared with classical immersion test results. The main result was that the agitation/flow rate had the greatest impact, with stagnant conditions giving very conservative results, followed by imax, which had an influence on the repassivation potential.