Grain growth of β-silicon nitride in RE-Mg-Si-O-N liquid

Noritaka Saito, Daiji Nakata, Ayumu Umemoto, Kunihiko Nakashima

    研究成果: ジャーナルへの寄稿学術誌査読

    3 被引用数 (Scopus)


    Isothermal growth of β-Si3N4 crystals dispersed in a series of rare-earth (RE = Y, Gd, Nd and La) oxynitride liquids (RE-Mg-Si-O-N) was studied after heat treatment at 1773K for 1 to 8 h. The microstructural characterization of α- and β-Si3N 4 crystals was quantitatively analyzed by electron microscopy. The number of α-Si3N4 crystals in oxynitride glasses decreased and that of β-Si3N4 crystals gradually increased with heat treatment time. And the mean grain size of β-Si 3N4 crystals also increased. It is determined that the rate of α/β transformation in the oxynitride liquid with Y 2O3 additive can be faster than that in oxynitride liquids with other additives. Likewise, the radii of rare-earth elements make significant differences in the mean grain size and aspect ratio. In all cases mentioned above, a marked change was observed in the order of ionic radius from La to Y. The mean diameter of the needlelike β-Si3N4 crystals heat-treated with La2O3 additive was almost constant in the time range of heat treatment in this study. However, the aspect ratio of β-Si3N4 crystals with La2O 3 additive was found to be much larger than that in oxynitride liquids with other additives, indicating negligible growth of β-prism plane.

    ジャーナルKey Engineering Materials
    出版ステータス出版済み - 1月 1 2005

    !!!All Science Journal Classification (ASJC) codes

    • 材料科学(全般)
    • 材料力学
    • 機械工学


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