NEXAFS N K-edge study of the bonding structure on Al/Si doped sputtered CrN coatings

Chromium nitride (CrN)-based materials display broad applications as protective coatings for automotive, power generation and aerospace industries, in which surfaces are often subjected to wear and corrosion. By using an appropriate choice of dopant, one can further increase the mechanical hardness, corrosion and oxidation resistance of these coatings. In order to identify the effect of dopants on the structural evolution and surface electronic properties of CrN coatings, Cr1-z(Al/Si)zN coatings were prepared by magnetron sputtering and then characterized via X-ray diffraction (XRD) and soft X-ray synchrotron radiation Near-edge X-ray Absorption Fine Structure (NEXAFS) studies around N K-edge. Higher degree of crystallinity of the coatings were identified through XRD studies. The bonding structure, of the doped CrN coating, was analyzed by Near-edge X-ray Absorption Fine Structure (NEXAFS) measurements performed around the N K-edge (390–450 eV) in the Auger electron yield (AEY) and total fluorescence yield (TFY) modes. NEXAFS analysis revealed Cr3d(Al3p/Si3p)N2p hybridizations in Cr1-z(Al/Si)zN compositions and complex structure splitting via spin–orbit interaction of the Cr3d levels.