| Project/Area Number |
03805058
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | Tohoku University |
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Principal Investigator |
WASEDA Yoshio Institute for Advanced Materials Processing, Tohoku University, Professor, 素材工学研究所, 教授 (00006058)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Kazumasa Institute for Advanced Materials Processing, Tohoku University, Research Associa, 素材工学研究所, 助手 (40196762)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1992: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | amorphous-ZrO_2 / sol-gel method / radial distribution function / stabilized ZrO_2 / crystallization / anomalous X-ray scattering / ゾルーゲル法 |
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| Research Abstract |
The sol-gel technique using metal alkoxides and other metal organic compounds as master materials has been developed for making various advanced materials and ZrO_2 is known to be included in this category. Thermal decomposition of amorphous-ZrO_2(a-ZrO_2) obtained by this sol-gel method produces a metastable tetragonal-ZrO_2(t-ZrO_2) in addition to monoclinic-ZrO_2(m-ZrO_2). In order to clarify this crystallization behavior, we analyzed the structure of a- ZrO_2 systematically. Two kinds of a-ZrO_2 were prepared by the hydrolytic condensation of Zr(OC_4H_9)_4 and the aqueous solution of ZrOCl_2+8H_2O. The anomalous X-ray scattering technique has been applied to obtain the environmental radial distribution function around a zirconium. Zirconium is quantitatively confirmed to be coordinated by six oxygens at a distance of 0.214nm and this Zr-octahedron is surrounded by other four octahedra at a distance of 0.341nm. This typical local ordering is suggested to be similar to that in the structure of m-ZrO_2 rather than that of t-ZrO_2. The structure of REE(Y or Er) substituted a-ZrO_2 have been analyzed in similar way. The typical local structure was not changed by the addition of REE elements to the a-ZrO_2, although cubic-ZrO_2 is produced by the crystallization of REE substituted a-ZrO_2. Therefore, it is rather suggested that the crystallization behavior is independent of the structural feature of a-ZrO_2 in this system. The research by using X-ray small-angle diffraction is strongly required for discussing the structural inhomogeneity in a-ZrO_2, which is one of the characteristic natures of the materials produced by sol-gel technique.
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