Crystallographic Dissolution of Potentiostatic Etching of Stainless Steel with Coarse Columnar Crystals

Abstract

The effects of surface orientation on dissolution rate of type 310S stainlesssteel with coarse columnar crystals were investigated by potensiostatic etchingin the active region in H₂SO₄-KSCN and H₂SO₄-NaCl solutions. {100} - {110} and {110} - {111} planes were prepared by cutting at 90° and 45° to <100>growth direction of the columnar crystals. Flat surfaces were formed on individualgrains after etching. The dissolution rate changed with the etchingpotentials and solutions. The ordersof the dissolution rate on the Ihk11surface, V_<hkl>, were as follows: V_<100><V_<111><V_<110> at -0.3V (vs.SCE) in 0.5kmol·m^-3-H₂SO₄+10mol·m^-3-KSCN solution and V_<110><V_<111><V_<100> at-0.26V in 2.5kmol·m-3-H₂SO₄+0.8kmol·m^-3-NaCI solution. Residual planesin each condition were determined from these dissolution rate ratios.