2000 Fiscal Year Final Research Report Summary
Development of sintering and joining processes of high performance ceramics for next generation by using high power millimeter-wave radiation
| Project/Area Number |
10555249
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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 |
Material processing/treatments
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| Research Institution | Osaka University |
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Principal Investigator |
MIYAKE Shoji Osaka University, Joining and Welding Research Institute, Prof., 接合科学研究所, 教授 (40029286)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Saburou National Industrial Research Institute of Nagoya, セラミックス応用部, 主任研究官
SETSUHARA Yuichi Osaka University, Joining and Welding Research Institute, Research Assoc., 接合科学研究所, 助手 (80236108)
MAKINO Yukio Osaka University, Joining and Welding Research Institute, Assoc.Prof., 接合科学研究所, 助教授 (20089890)
SAJI Tazaburou Gamo Laboratory, Director, 所長(研究職)
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| Project Period (FY) |
1998 – 2000
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| Keywords | millimeter-wave / sintering / nitride / silicon nitride / aluminum nitride / sintering aids / selective heating |
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| Research Abstract |
Sintering and joining processes based on millimeter-wave radiation were developed for fabricating high performance ceramics and fundamental properties of ceramics powders were investigated by using millimeter-wave spectroscopy. Following results were obtained.
In the research on clarifying the dielectric characteristics of ceramics powders in the millimeter-wave region, power absorption of silicon carbide powder was first measured by millimeter-wave spectroscopy and it was found that the absorption coefficient increased with increasing the powder size, temperature and the content of free carbon. Secondly, the dielectric constant of alumina-zirconia showed high values with decreasing powder density and increasing zirconia content.
New sintering aids containing Yb_2O_3 were developed for sintering silicon nitrides with 28GHz millimeter-wave radiation and a rapid sintering process was successfully established for fabricating bulk silicon nitrides which were sintered within only one hour lower a temperature which was lower by about 400℃ than those in conventional methods. The rapid millimeter-wave sintering process was also applied to the fabrication of aluminum nitride with high thermal conductivity of about 190 W/m・K was successfully produced at a temperature of 200℃ lower and at a sintering time of one-tenth shorter than those in conventional methods.
Subsequently, as an example of fabricating nanocrystalline bulk materials, consolidation of nano-powder anatase was investigated by millimeter-wave heating, resulting in obtaining porous bulk titania with 200 nm in the average diameter with 300 Hv in the hardness.
Further, focused millimeter-wave beam process enabled to crystallize amorphous SrTiO_3 films at a low temperature below 400℃ and well-crystallized SrTiO_3 films with high dielectric constant similar to polycrystalline bulk SrTiO_3 was synthesized successfully.
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