Abstract
Electrochemical polarization measurements have been made on 
Type 304 and USS 18‐18‐2 stainless steels in magnesium chloride boiling at 150°C. Little difference in the cathodic Tafel constant was noted; the observed values being equal to that expected from a charge transfer rate‐determining step. Steady‐state corrosion currents increased in the order Type 304 > USS 18‐18‐2 for the unstressed and the stressed condition. Analysis of corrosion potential vs. time and cyclic polarization data indicates the presence of a film on the corroding surface, which affects the corrosion kinetics. The presence of two mixed potentials during cyclic polarization does not support the noble metal enrichment concept of crack propagation, but rather, the film rupture model.