| Project/Area Number |
13555175
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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 | Nagasaki University |
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Principal Investigator |
EGASHIRA Makoto Nagasaki University, Faculty of Engineering, Professor, 工学部, 教授 (60037934)
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| Co-Investigator(Kenkyū-buntansha) |
USHIJIMA Hitoshi Yazaki Parts Co., Ltd., Advanced Material R&D Division, Team Leader, 部材開発事業部・材料開発部, リーダー
HYODO Takeo Nagasaki University, Faculty of Engineering, Research Associate, 工学部, 助手 (70295096)
SHIMIZU Yasuhiro Nagasaki University, Graduate School of Science and Technology, Associate Professor, 生産科学研究所, 助教授 (20150518)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2001: ¥11,200,000 (Direct Cost: ¥11,200,000)
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| Keywords | Alumina / PMMA / Silica / Mechanofusion / Hybridization / Thermal decomposition / Aluminum nitrate / Ultrasonic spraying / 中空粒子 |
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| Research Abstract |
Design and processing of hollow ceramic microspheres and hybrid ceramic/polymer microparticles were attempted as below.
1. Preparation of ceramic microspheres by utilizing a mechanofusion system Core/shell structure was prepared by a mechanofusion system by employing several kinds of spherical polymers as a core material and Al_2O_3 powder or a mixture of Al_2O_3 and SiO_2 powder as a shell material. A large fraction of hollow alumina microspheres reflecting the shape and the particle size distribution of the core polymer could be fabricated after sintering at 1600℃ for 3h, when highly cross-linked PMMA microspheres with a gel fraction of ca. 99% were used as a core polymer and abrupt firing at temperatures higher than 500℃ was adopted to remove the PMMA microspheres. Titania microspheres were also prepared by employing the similar technique.
2. Preparation of ceramic microspheres by utilizing a hybridization system Hybrid alumina/PMMA microparticles were prepared by utilizing a hybridiz
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ation system by employing PMMA microparticles and Al_2O_3 powder as a raw material. However, hollow microspheres were scarcely obtained even after calcination at 1600℃, because the Al_2O_3 powder could not be coated around the PMMA microparticles sufficiently.
3. Preparation of ceramic microspheres by ultra-spray pyrolysis Alumina microsphreres were successfully fabricated by ultrasonic spraying of 0.5 M Al(NO_3)_3 aqueous solution, followed by instantaneous thermal decomposition and calcination at 1300℃. The crystal phase of as-prepared microspheres was δ-Al_2O_3, but turned into α-Al_2O_3 after post-calcination at 1300℃ for 2h. In addition, some microspheres were changed from solid to hollow structure by the post-calcination. The fraction of hollow microspheres in the resultant products was less than 30% and the mean diameter of these microspheres was 0.7 μm under these preparation conditions. However, the fraction could be increased up to 80% by the addition of a small amount of a surfactant to the precursor solution.
4. Fabrication of aluminum/hollow alumina microspheres composites Aluminum/hollow alumina microspheres composites were fabricated by a liquid forging technique by employing aluminum ingot (ADC-12 ; Al>84.4%) and hollow alumina microspheres prepared by a mechanofusion system. The composites showed the highest flexural strength, compared with those prepared from commercially produced alumina bubbles, fly ash and silas balloons. Less
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