Grain growth of β-silicon nitride in RE (RE = Y, Gd, Nd and La) -Mg-Si-O-N melts

Daiji Nakata, Noritaka Saito, Ayumu Umemoto, Kunihiko Nakashima

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Isothermal growth of β-Si 3N 4 crystals dispersed in rare-earth (RE = Y, Gd, Nd and La) oxynitride melts (RE-Mg-Si-O-N) was studied during heat treatment at 1773 K under 0.9 MPa of nitrogen pressure for 64 to 512 min. The microstructure of β-Si 3N 4 crystals was characterized by electron microscopy. It is found that the rate of α-β transformation increases with decreasing ionic radius of the rare-earth element. Likewise, the radii of rare-earth elements make significant differences in the morphology and mean aspect ratio of β-Si 3N 4. Especially, the aspect ratio of β-Si 3N 4 crystals with the additive of La 2O 3 was found to be much larger than that in oxynitride melts with additives of others.

Original languageEnglish
Pages (from-to)719-722
Number of pages4
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Issue number8
Publication statusPublished - Aug 1 2005


All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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