Anodic Polarization Behavior Of Cold Worked Austenitic Stainless Steel

摘要

The anodic polarization behavior of an Sanicro 28 austenitic stainless steel has been established in the cold worked (10 to 80% reduction in thickness) state in IN HCl, 1M H_2SO_4+ 1.5N HCl and3N HC1 solutions at room temperature. Current oscillations during the potentiodynamic scans appeared in 3N HCl implying the formation of metastable pits and this was more severe in this solution than in 1NHCl and 1M H_2SO_4+ 1.5N HCl. Two anodic peaks were observed in potentiodynamic polarization scanes of the as-received and cold worked samples in 3N HCl. In the as-received state, the first anodic peak appeared at -3.95 mV_(SCE) and the second at 116 mV_(SCE). Selective dissolution commenced from 18 mV_(SCE). The grains and grain boundaries were not attacked at the beginning of the first peak -168 mV_(SCE) and started to be revealed at 18 and 216 mV_(SCE) in the potentiodynamic polarization test. The fore-scatter detector (FSD) attached to FEI Quanta EBSD revealed the morphology of the pits. The pit dimensions, types, distribution and shape, in all deformation conditions, is hemispherical and number of pits did not depend strongly on the microstructural features, irrespective of the level of plastic deformation.