Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2707

Full Length Research Paper

Thermal treatment in air of direct current (DC) magnetron sputtered TiN coatings

Naim Syla*
  • Naim Syla*
  • Department of Physics, FMNS, University of Prishtina, Mother Theresa Str.5, KS-10000 Prishtina, Kosovo.
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Heinrich Oettel
  • Heinrich Oettel
  • Institute of Materials Science, TU Bergakademie Freiberg, Gustav-Zeuner Str.5, D-09559 Freiberg, Germany.
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Teuta Dilo
  • Teuta Dilo
  • Department of Physics, FNS, University of Tirana, Boulevard Zogu I, Tirana, Albania.
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Fisnik Aliaj
  • Fisnik Aliaj
  • Department of Physics, FMNS, University of Prishtina, Mother Theresa Str.5, KS-10000 Prishtina, Kosovo.
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  •  Received: 16 September 2016
  •  Accepted: 05 October 2016
  •  Published: 15 November 2016

Abstract

TiN coatings were deposited onto mirror polished stainless steel substrates by reactive DC magnetron sputtering using a pure Ti target and Ar+N2 atmosphere. The deposited TiN coatings were thermally treated in ambient air at temperatures ranging from 500 to 700°C for times between 1 and 16 h. The as-deposited and thermally treated coatings were characterized using glow discharge optical emission spectroscopy, x-ray diffraction and scanning electron microscopy. Titanium oxide layers were identified at the surface of thermally treated TiN coatings, which grow according to oxygen diffusion controlled parabolic time law. Phase composition of the oxide layers is found to depend strongly on temperature and exposure time. At low temperatures and shorter exposure times the oxide layers were found to be a mixture of anatase and rutile polymorphs of TiO2, while at high temperatures and longer exposure times the oxide layers consisted only of the rutile polymorph of TiO2. The results show that the microstructure of the oxide layers is porous and non-uniform across the oxide layer thickness. The porous microstructure is explained by the accumulation of nitrogen by short-range diffusion and transition into a gaseous state.

Key words: TiN, coating, magnetron sputtering, rutile, thermal treatment, X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GD-OES).