| Project/Area Number |
13450360
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
無機工業化学
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| Research Institution | Kanagawa Institute of Technology |
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Principal Investigator |
IKAWA Hiroyuki Kanagawa Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30016612)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEMOTO Minoru Kanagawa Institute of Technology, Faculty of Engineering, Research Associate, 工学部, 助手 (70288215)
SHIRAKAMI Tatsuya Ryukoku University, Faculty of Science and Technology, Research Associate, 理工学部, 助手 (50257416)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2002: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2001: ¥8,800,000 (Direct Cost: ¥8,800,000)
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| Keywords | barium titanate / ferroelectric twin / phase transformation / size effect / small particle / Raman spectrum / 強誘電体 / 微粉子 |
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| Research Abstract |
The following commercially available barium titanate powders were investigated with the intentions t find the size of the smallest tetragonal particle. Those were hydrothermal barium titanate made by Sakai Chemical Industry Co., Ltd ; BT-01 and BT-006 with respective nominal sizes of 100 nm and 6 nm, respectively. Another powder of KCM Corp., was made by a solid state reaction with a nominal size of 700 nm.
The latter powder was CIPed under 1GPa repeatedly at room temperature to characterize by powder X-ray diffraction, TEM and heat capacity measurements. The tet-cub transformation enthalpy of the CIPed once powder was 1/15 of that of the normal. However, it was tetragonal after CIPed for 60 times although the crystallite size was decreased to 47 nm. Further, tweedy and /or squeezed texture was revealed by TEM to comprise collapsed boundary zones and modulated lattice arrays.
Some papers have reported about cubic barium titanate of BT-01. However, this research made it clear that all the
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powders were tetragonal for as received BT-01 ad BT-006, and their heated specimens. This conclusion was derived from following results, however, even very careful electron diffraction examinations failed to detect any tetragonalty on as received powder of BT-01. The half height widths of 113 and 400 diffractions were monitored as functions of temperature to find their reversible changes. These results said that the half height widths of the two diffractions were wide at room temperature because of their tetragonal splittings, and those became smaller at higher temperature that Tc.
Systematic measurements of Raman spectrum as functions of temperature supported the tetragonal barium titanate of hydrothermal powders. We had detected on specimens the inhibited spectra for cubic barium titanate at 150℃. That is the inhibited spectra are no use to identify the point group of the crystals. However, we had monitored the sharp reversible changes in intensities of inhibited spectra at transformation temperatures to conclude the specimens were tetragonal barium titanate at a room temperature. Less
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