Chromium Nitride by XPS

Chromium nitride (CrN) coatings have been deposited on polished steel substrates by a plasma-beam sputtering technique in a Sputron apparatus (Balzers A. G.) at 200 °C. A thin intermediate layer of Cr (0.08 μm) was deposited between the substrate and the 2.8 μm thick CrN coating. The average roughness, R_a, of the substrate was <0.04 μm, whereas after the deposition R_a values between 0.06 and 0.08 μm were measured for CrN coatings. Coatings exhibit a fine grain structure of the grain size <100 nm. The XPS measurements were performed in an Escalab 200-X spectrometer (VG Instruments) using non-monochromatized Al K_α radiation from a twin Mg/Al anode operating at 300 W. The hemispherical energy analyzer was operated in the CAE mode with a constant pass energy of 20 eV. In the present paper the following spectra are presented: survey spectrum, spectra of major elements chromium and nitrogen (Cr 2p and N 1s), spectra of minor elements oxygen and carbon (O 1s and C 1s), and valence band spectrum. Spectra were background subtracted using a Shirley method. Peak positions and widths were determined from a least squares fitting procedure.