EELS on ordered chromium compounds formed on multicomponent Fe15%Cr-X(100) alloy surfaces

The segregation and the formation of stable surface compounds on a Fe15%Cr(100) surface have been studied with high-resolution electron energy loss spectroscopy (EELS), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). After cosegregation of Cr and N to the surface the EEL spectrum shows a loss at 520 cm−1, which corresponds to the frequency of the stretching vibration of N atoms on the Cr enriched surface. After cosegregation of Cr and C atoms the EEL spectrum exhibits a single loss at 480 cm−1, which is attributed to the stretching vibration of C atoms within the CrC surface compound. The loss at 275 cm−1, found in the EEL spectrum recorded after the cosegregation of Cr and S on the surface, is attributed to the stretching vibration of S atoms adsorbed in fourfold hollow sites.