TY - GEN
T1 - Grain growth of β-silicon nitride in RE-Mg-Si-O-N liquid
AU - Saito, Noritaka
AU - Nakata, Daiji
AU - Nakashima, Kunihiko
AU - Umemoto, Ayumu
PY - 2006/7/26
Y1 - 2006/7/26
N2 - 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 1773 K for 64 to 512 min, The microstructural characterization of α- and β-Si3N 4 crystals was quantitatively analyzed by electron microscopy, The volume fraction of β-Si3N4 crystals in oxynitride glasses increased with heat treatment time, It is determined that the rate of α/β transformation in the oxynitride liquid with Y2O 3 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 of β-Si 3N4 crystals, In all cases mentioned above, a marked change was observed in the order of ionic radius from La to Y, The mean width 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-Si 3N4 crystals with La2O3 additive was found to be much larger than that in oxynitride liquids with other additives, indicating negligible growth of β-prism plane.
AB - 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 1773 K for 64 to 512 min, The microstructural characterization of α- and β-Si3N 4 crystals was quantitatively analyzed by electron microscopy, The volume fraction of β-Si3N4 crystals in oxynitride glasses increased with heat treatment time, It is determined that the rate of α/β transformation in the oxynitride liquid with Y2O 3 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 of β-Si 3N4 crystals, In all cases mentioned above, a marked change was observed in the order of ionic radius from La to Y, The mean width 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-Si 3N4 crystals with La2O3 additive was found to be much larger than that in oxynitride liquids with other additives, indicating negligible growth of β-prism plane.
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M3 - Conference contribution
AN - SCOPUS:33746267395
SN - 0470082909
SN - 9780470082904
T3 - Ceramic Transactions
SP - 73
EP - 80
BT - Developments and Applications of Advanced Engineering Ceramics and Composites - Proceedings of the 6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6
T2 - 6th Pacific Rim Conference on Ceramic and Glass Technology, PacRim6
Y2 - 11 September 2005 through 16 September 2005
ER -