The crystallography of interphase boundaries between silicon carbide and silicon nitride in silicon nitride - Silicon carbide particulate composites

Turan S., Knowles K.

INTERFACE SCIENCE, vol.8, no.2-3, pp.279-294, 2000 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 8 Issue: 2-3
  • Publication Date: 2000
  • Doi Number: 10.1023/a:1008724002737
  • Journal Name: INTERFACE SCIENCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.279-294
  • Keywords: crystallography, engineering ceramics, interphase boundaries, silicon carbide, silicon nitride, IMPROVED FRACTURE-TOUGHNESS, WHISKER-REINFORCED SI3N4, MICROSTRUCTURAL DESIGN, CVD SI3N4, INTERFACE, NANOCOMPOSITES, THICKNESS, PHASE
  • Anadolu University Affiliated: No

Abstract

Interphase boundaries between 3C SiC grains and two different beta-Si3N4 morphologies in Si3N4-SiC composites have been studied by transmission electron microscopy. In general, boundaries between small beta-Si3N4 intragranular precipitates and surrounding SiC grains were relatively free of intergranular films, whereas boundaries between large beta-Si3N4 grains and adjacent SiC grains were invariably covered with thin intergranular films. Orientation relationships approximating to [110] 3C SiC parallel to [0001] beta-Si3N4 and (001) 3C SiC parallel to (10 (1) over bar 0) beta-Si3N4 were found to dominate between 3C SiC grains and the intragranular beta-Si3N4 precipitates, but there was no evidence of any favoured orientation relationship between the large beta-Si3N4 grains and adjacent SiC grains. The rationale for 'special' orientation relationships arising when there is no intergranular film present at 3C SiC-beta-Si3N4 interfaces is explored geometrically using the near-coincidence site lattice model, with the significant result that the dominant orientation relationships between 3C SiC grains and the intragranular beta-Si3N4 precipitates have low misfits relative to all other possible orientation relationships between 3C SiC and beta-Si3N4.