XPS characterization of surface layers of stainless steel nitrided in electron beam plasma at low temperature.

The results of the influence of low-temperature plasma nitriding at 350 °C on the Cr N and Fe N bonds formation of Fe-Cr-Ni austenitic steel before and after nanostructure frictional treatment are presented. The measurements of high-energy resolved X-ray photoelectron Fe 2p, Cr 2p, Ni 2p and N 1s spectra and valence bands (VB) showed that chromium and iron form Cr N and Fe N bonds whereas the nickel is in metallic state. It is concluded that the expanded austenite formed directly on the surface of the steel after low temperature plasma nitriding can be classified as a nanocomposite medium consisting of Cr N and Fe N clusters dispersed in a Fe-Cr-Ni-N matrix. • Formation of Fe–N and Cr–N bonds at 350 °C is reported. • Ni atoms presented in metallic state • Nitrogen atoms show a strong heterogeneity in the form of nano-scale 'nitrogen clouds' surrounding Cr and Fe atom clusters. [ABSTRACT FROM AUTHOR]