Crystallographic effects in corrosion of austenitic stainless steel 316L

Electron backscatter diffraction and confocal laser microscopy have been used to quantify the degree of crystallographic anisotropy during corrosion of AISI 316L in two test solutions. Corrosion in 30vol% H2SO4 sulphuric acid shows pronounced crystallographic anisotropy in which the corrosion rate increases in the order {111}<{110}less than or similar to{100}. The ratio between the slowest corroding {111} and the fasting corroding {100} surfaces is about 3. Pitting corrosion in a solution of FeCl3 and AlCl3 in ethanol/glycerol agrees with other reported observations that high-atomic density surfaces {111} and {100} are less prone to pit nucleation, however the effect was relative small.