The effect of indenter shape on the transient current response and surface microstructures in Fe-16wt.% Cr-16wt.%Ni alloy

Abstract The effect of indenter shape on the transient current response of Fe-16 wt.%Cr-16 wt.%Ni alloy has been investigated in an 0.01 M H 2 SO 4 -0.01 M KCl electrolyte. Various Rockwell hardness indenters with C-Brale, Vickers, 1 16 in and 1 8 in balls at their tips have been used in this study to produce scratches of different shapes on the alloy when the specimen was being rotated at 1500 rev min −1 in the given electrolyte. The transient current increases linearly with increasing impact force of the stylus. The transient current response in itself indicates various stages corresponding to passivation, depassivation and repassivation kinetics of the samples. The details of the kinetics have been discussed in this paper. The scanning electron micrographs indicate that the area of the scratches increased with increasing applied load, and the morphologies of the scratches appear to be quite different in air and electrolyte. The scratches are usually more elongated in the electrolyte.