First-principles investigation of titanium doping into β-SiAlON crystal in TiN-SiAlON composites for EDM applications

Kandemir A., SEVİK C., Yurdakul H., TURAN S.

Materials Chemistry and Physics, vol.162, pp.781-786, 2015 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 162
  • Publication Date: 2015
  • Doi Number: 10.1016/j.matchemphys.2015.07.003
  • Journal Name: Materials Chemistry and Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.781-786
  • Keywords: Ceramics, Ab initio calculations, Electrical properties, LIGHT-EMITTING-DIODES, ELECTRONIC-STRUCTURES, LUMINESCENCE PROPERTIES, OPTICAL-PROPERTIES, SILICON-NITRIDE, PHOSPHORS, PHASE, SI6-ZALZOZN8-Z, OXYNITRIDE, CERAMICS
  • Anadolu University Affiliated: Yes

Abstract

© 2015 Published by Elsevier B.V.Abstract Following the experimental work on the incorporation of titanium into β-SiAlON crystal in TiN-SiAlON composites for electrical discharge machining (EDM) applications, Ti doping mechanisms in β-Si6-z AlzOzN8-z have been systematically investigated by means of density functional theory based formation energy calculations. A series of calculations, performed considering the random distributions of Ti-O/N, Al-O/N, and Si-O/N bonds in β-Si6-z TizOzN8-z crystal, showed that the structures with enriched Ti-O and Si-N bonds have lower formation energy than those of Ti-N and Si-O bonds. In addition, it was determined that there is a notable difference between the average bond lengths of Ti-X and Al-X (X=O, N). Electronic structure calculations demonstrated that there is no correlation between either the z values or the number of Ti-O bonds and the one-electron band gap. However, in the case of β-Si6-z AlzOzN8-z, there was a decreasing trend regarding the energy on one-electron band gap with respect to increasing z values.