| Co-Investigator(Kenkyū-buntansha) |
KOZUKA Hiromitsu Kyoto University, Institute for Chemical Research, 化学研究所, 助手 (80178219)
MAKI Toshio Kyoto University, Institute for Chemical Research, 化学研究所, 助手 (30027031)
KOKUBO Tadashi Kyoto University, Institute for Chemical Research, 化学研究所, 教授 (30027049)
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| Research Abstract |
This study has been undertaken to find the structure of gallate, aluminate and titanate glasses which do not contain conventional network formers such as SiO_2, B_2O_3, GeO_2, P_2O_5 and As_2O_3. These glasses are characterized by infrared transmittance and ionic conduction and the study of the structure of the glasses is expected to contribute to materials design, that is, to exploring the relation between the composition and characteristic properties.
X-ray radial distribution analysis, Raman spectroscopy and measurement of chemical shift of X-ray fluorescence have been made on binary and ternary glasses of the compositions of alkali or alkaline earth gallates, aluminates and titanates to elucidate their structure. It has been found that in all those glasses most of the major cations, that is, Ga^<3+>, Al^<3+> and Ti<@14+<@D1 ions that may assumingly form glass networks are in four coordination relative to oxygens. This indicates that Zachariasen's theory on glass formation and glass networks is also valid for gallate, aluminate and titanate glasses. Zachariaxen's theory states that oxide glass formation occurs when metal cations have a small coordination number (3 Or 4) with oxygen and polyhedral structural units MO3 and MO4, Where M is a metallic atom, are connected at the corner of the polyhedron, sharing an oxygen. Besides the glass structrues, the composition dependences of density, thermal expansion and electrical ave also been investigated in gallate and aluminate glasses. As a result of the above mentioned studies, the materials design of gallate, aluminate and titanate glasses became possible.
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