High Resolution STEM and EDS FIB-SEM Study of Chromium Depletion in Stainless Steel

This application note describes a study of heat affected X2CrNi18-10 stainless steel. Small chromium carbide particles form at the grain boundaries of the material, causing chromium depletion of the surrounding matrix and thus promoting corrosion. A thin lamella was prepared at a grain boundary and analyzed with scanning transmission electron microscopy (STEM) and energy dispersive spectroscopy (EDS) by a ZEISS FIB-SEM instrument. The EDS results obtained on the lamella show a spatial resolution of the order of 10 nm and allow the extent of the chromium depletion to be qualitatively determined.