日本金属学会誌

J. Japan Inst. Metals, Vol. 71, No. 11 (2007),
pp. 1050-1056

Viscosity of RE-Mg-Si-O-N(RE=Y, Gd, Nd and La) Melts

Sohei Sukenaga1, Daiji Nakata1, Tomoyasu Ichiki2, Noritaka Saito1 and Kunihiko Nakashima1

1Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395
2Sanitary Ware Division, TOTO Ltd. Kitakyuhu 802-8601

Abstract:

Viscosities of the molten RE-Mg-Si-O-N(RE=Y, Gd, Nd and La) glasses have been measured using a newly-developed rotational viscometer with gas tight furnace. Effects of nitrogen and rare-earth additives on the viscosities of RE-Mg-Si-O-N melts have been investigated systematically at elevated temperature (∼1873 K).
The viscosities of molten RE-Mg-Si-O-N glasses exponentially increased with nitrogen content, which indicates that the substitution of nitrogen for oxygen in the melts may lead to a high average coordination of nonmetal atoms, and that the increase of cross-linking produces a more rigid network structure. The viscosities of RE-Mg-Si-O-N melts were found to decrease in the order of cationic radius of rare-earth elements, which suggests that larger rare-earth elements behave as a stronger network modifier of complex silicate or silicon-oxynitride anions in elevated temperature melts. Additionally, the viscosity of the smaller rare earth containing oxynitride melt indicated more sensitive increase with nitrogen content.


(Received 2007/6/7)

Keywords:

molten oxynitride, rare-earth elements, viscosity, cationic radius of rare-earth


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