Nitridation of silicon powder studied by XRD, 29Si MAS NMR and surface analysis techniques

K. J.D. MacKenzie, C. M. Sheppard, K. Okada, Y. Kameshima

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The nitridation of elemental silicon powder at 900-1475 °C was studied by X-ray photoelectron spectroscopy (XPS), X-ray excited Auger electron spectroscopy (XAES), XRD, thermal analysis and 29Si MAS NMR. An initial mass gain of about 12% at 1250-1300 °C corresponds to the formation of a product layer about 0·2 μm thick (assuming spherical particles). XPS and XAES show that in this temperature range, the surface atomic ratio of N/Si increases and the ratio O/Si decreases as the surface layer is converted to Si2N2O. XRD shows that above 1300 °C the Si is rapidly converted to a mixture of α- and β-Si3N4, the latter predominating >1400 °C. In this temperature range there are only slight changes in the composition of the surface material, which at the higher temperatures regains a small amount of an oxidised surface layer. By contrast, in the interval 1400-1475 °C, the 29Si MAS NMR chemical shift of the elemental Si changes progressively from about -80 ppm to -70 ppm, in tandem with the growth of the Si3N4 resonance at about -48 ppm. Possible reasons for this previously unreported change in the Si chemical shift are discussed.

Original languageEnglish
Pages (from-to)2731-2737
Number of pages7
JournalJournal of the European Ceramic Society
Volume19
Issue number16
DOIs
Publication statusPublished - Dec 1999
Externally publishedYes

Keywords

  • Nitridation
  • SiN
  • Silicon.
  • X-ray methods

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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