Thermal stability of yittrium-and-neodymium-doped alpha/beta-SiAlON ceramics

Kurama S., Herrmann M.

SILICATES INDUSTRIELS, vol.69, no.7-8, pp.241-248, 2004 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 69 Issue: 7-8
  • Publication Date: 2004
  • Journal Name: SILICATES INDUSTRIELS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.241-248
  • Keywords: alpha-SiAlON, stability region, Rietveld analysis, thermal stability, SUBSOLIDUS PHASE-RELATIONSHIPS, SYSTEM SI,AL,Y/N,O
  • Anadolu University Affiliated: No

Abstract

A series of samples of yttrium and neodymium containing alpha-SiAlON (Rx+vSi12-(m+n)Alm+nOnN16-n with R = Y, Nd) has been synthesised at different temperatures and isothermal sintering times. The Rietveld technique was used for the determination of the x value of the alpha-SiAlONs. This method offers the possibility to determine the boundaries of two phase field beta-SiAlON/alpha-SiAlON with a high accuracy. On the basis of these data, the stability regions of Y- and Nd-alpha-SiAlONs were established at different temperatures. At n-values less than 0.5 x-values as low as 0.24 +/- 0.02 for Y and 0.30 +/- 0.02 for Nd-alpha-SiAlON were observed. The m values at the boundary of the stability region are nearly independent on the temperature (1650 - 1900degreesC).