alpha-SiAlON ceramics densified with mixed oxide sintering additives

Mandal H., Oberacker R., Hoffmann M., Thompson D.

NITRIDES AND OXYNITRIDES, vol.325-3, pp.207-212, 2000 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 325-3
  • Publication Date: 2000
  • Doi Number: 10.4028/
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.207-212
  • Keywords: SiAlON, densification, phase transformation, new alpha-SiAlONs
  • Anadolu University Affiliated: No


Densification and stabilization of alpha-sialon ceramics were investigated by using oxides of large cations (Sr2+, La3+, Ce3+, Nd3+) and their equi-molar mixtures with CaO or Yo(2)O(3). All multi-cation and single cation (only Nd3+ and Ce3+) doped samples could be densified to nearly full density even by pressureless sintering. X-ray diffraction of the samples densified with single cations revealed that the ol-sialon structure could accomodate Nd3+ or Ce3+ cations. In Sr- and La- systems, however, S- (similar to SrO:1.3A1(2)O(3):0.7Si(2)N(2)O) and N- (La3Si8O4N11) phases were found to be stable rather than a-sialon. In case of multi-cations, alpha-sialon was observed only as a matrix phase. EDX measurements proved that Ce-, La- and Sr- cations could be accomodated into the alpha-sialon structure with the presence of calcium or ytterbium. SEM studies revealed that almost glass free grain boundaries could be obtained by careful design of starting compositions.