The effect of heat treatment on structural and electronic properties of niobium nitride prepared by a thermal diffusion method

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Farha A. H. , Ozkendir O. M. , Elsayed-Ali H. E. , Myneni G., UFUKTEPE Y.

SURFACE & COATINGS TECHNOLOGY, vol.309, pp.54-58, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 309
  • Publication Date: 2017
  • Doi Number: 10.1016/j.surfcoat.2016.11.044
  • Page Numbers: pp.54-58


Niobium nitride (NbNX) coatings were prepared onto Nb substrate by thermal diffusion at high temperatures. The formation of NbNX coating by thermal diffusion was studied in the range of 1250-1500 degrees C at constant nitrogen background gas pressure (1.3 x 10(-3) Pa) and processing time (180 min). The electronic and crystal structures of the NbNX coatings were investigated. It was found that nitrogen diffuses into Nb forming the Nb-N solid solution (bcc) alpha-NbN phase that starts to appear above 1250 degrees C. Increasing the processing temperature gives richer alpha-phase concentration. Besides, X-ray absorption spectroscopy (XAS) was performed to study the electronic structure of the NbNX layer. The results of the electronic structural study corroborate the crystal structural analysis. The Nb M-3,M-2 edge X-ray absorption spectroscopy (XAS) spectrum shows strong temperature dependence. At the highest processing temperature (1500 degrees C), the number of d holes increased. Electrostatic interaction between d electron and core hole was increased due to nitrogen diffusion into the niobium. For the studied conditions, only the alpha-NbN was observed in the X-ray diffraction patterns. (C) 2016 Elsevier B.V. All rights reserved.