1999 Fiscal Year Final Research Report Summary
Development of a newly designed ultraviolet Raman scattering system for in-site observation of structure at very high temperature
| Project/Area Number |
10555215
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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 | 展開研究 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
KAKIHANA Masato Tokyo Institute of Technology, Materials and Structure Laboratory, Associate Professor, 応用セラミックス研究所, 助教授 (50233664)
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| Co-Investigator(Kenkyū-buntansha) |
SIMIDZU Ryosuke Photon Design, Director, 代表
SAKAKI Satoshi Tokyo Institute of Technology, Materials and Structure Laboratory, Associate Professor, 応用セラミックス研究所, 助教授 (10162364)
YOSHIMURA Masahiro Tokyo Institute of Technology, Materials and Structure Laboratory, Professor, 応用セラミックス研究所, 教授 (10016826)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Raman scattering / ultra-violet light / thermal emission / in-site observation at high temperature / zirconia / hafnia / perovskite |
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| Research Abstract |
It is of prime importance to observe change in structure of ceramics in-situ at high temperature for controlling materials properties and compositions. In the field of ceramics, since the X-ray diffraction method is most frequently used for phase identification, the technique has been extended to in-situ observation of ceramic structure at high temperature. However, X-ray diffraction techniques are not always suitable for systems like ceramics, where positions of oxygen atoms play a crucial role in determining properties and phase transformations, or for samples comprised of ultra fine powders. For this reason, it is required to develop an alternative to the X-ray diffraction technique, which enables us to carry out studies at high temperatures. To achieve this requirement, we have developed a newly designed Raman scattering system combined with an ultra-violet excitation light source. In ordinary Raman scattering experiments, conventional visible light Ar lasers have been used as excitation sources for Raman spectra. Wavelengths most frequently used for Raman scattering include the blue line at 488 nm and the green line at 515 nm. However, in case where these visible lights are used for Raman scattering experiments at high temperature, a very strong background coming from thermal emissions interfere quite severely with the observation of relatively weak Raman scattering. To overcome this serious problem, we have designed a new Raman scattering system combined with an excitation source having a wave length 363 nm, which made possible to measure Raman spectra at temperatures even higher than 1500℃. We have successfully measured Raman spectra of various high temperature materials (hafnia, zirconia, and perovskite) and clearly observed their phase transformations in situ at high temperatures. For instance, the monoclinic-to-tetragonal transformation of hafnia finished around 2080 K on heating, while the monoclinic phase appeared at 2018 K on cooling.
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