XRD and AES/XPS Investigations of the Oxidation Behavior of High-Manganese Electrical Steel in Air

Alloying with Mn can significantly influence the magnetic behavior of soft-magnetic silicon steel. Therefore, the formation of high-temperature oxides on an Fe-Si-Al alloy for electrical steel with the addition of 1 wt.% Mn is investigated in this study. X-ray diffraction spectra of a high-manganese Fe-Si-Al alloy were measured at a series of increasing temperatures (from room temperature to 1200°C). Two main phases were identified (apart from Fe): cubic Fe3O4 and rhombohedral Fe2O3. With a temperature increase, their ratio changes, as observed from the diffraction-peak intensities. In spite of the complex chemistry of the initial material, no further phases were identified below 750°C. At higher temperatures, several new diffraction peaks were observed. Their possible attribution is discussed. The experimental part was supplemented by surface-sensitive x-ray photoelectron spectroscopy and Auger electron spectroscopy that were able to detect, of all the non-ferrous metals, only Cu on the sample’s surface.