Understanding the Effect of Applied Current and Potential on Pitting in 316L Stainless Steels

Abstract

The pit morphologies of Type 316 L stainless steel were evaluated with “sandwiched” foil electrodes to identify pit growth characteristics under galvanostatic and potentiostatic polarization through ex-situ and in-situ tests. The applied current and potential values influenced the pit morphologies and lacy cover formation. A direct correlation was found between the type of lacy cover and the observed pit morphologies. The faster pit depth growth occurred with only one opening on the lacy cover due to “pit dissolution induced convection,” while the shorter mass transfer path led to faster lateral pit growth with a perforated lacy cover or open pit.