3 0 0 0 OA アルミナ粉体-窒化ケイ素ウイスカー系サスペンションのレオロジー的性質と固化
- 著者
- 平田 好洋 松下 晋一 中釜 晋 石原 義巳 堀 三郎
- 出版者
- 公益社団法人日本セラミックス協会
- 雑誌
- 日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi (ISSN:18821022)
- 巻号頁・発行日
- vol.97, no.1129, pp.881-887, 1989-09-01
- 被引用文献数
- 5 14
Dispersion, rheology and consolidation of the colloidal suspension in the alumna powder-silicon nitride whisker system were studied to control the microstructure and density of the green compact. Al_2O_3 particles with au average diameter of 0.15 μm and Si_3N_4 whiskers with an average size of 0.4 μmX3.7μm were electrostatically dispersed in water in the pH range 3 to 10 and consolidated by filtration. Well- dispersed stable suspensions were obtained at low pH. Decreasing the viscosity and at the same time increasing the solid content of the suspension is the hey step in making the green compact with high density and a narrow pore size distribution. Application of isostatic pressing to compacts consolidated by filtration increased green density and shifted the pore size distribution to smaller size. These green compacts by colloidal processing were densities to relative densities of 98.4-99.4% by hot-pressing at 1500℃ at a pressure of 39 MPa in N_2 atmosphere.
1 0 0 0 OA 希土類固溶セリアの熱膨張
- 著者
- 鮫島 宗一郎 河南 学 平田 好洋
- 出版者
- The Ceramic Society of Japan
- 雑誌
- Journal of the Ceramic Society of Japan (日本セラミックス協会学術論文誌) (ISSN:09145400)
- 巻号頁・発行日
- vol.110, no.1283, pp.597-600, 2002-07-01 (Released:2010-08-06)
- 参考文献数
- 20
- 被引用文献数
- 38 51
The thermal expansion of CeO2 and rare-earth-doped ceria (Ce0.8R0.2O1.9, R: Yb, Y, Gd, Sm, Nd and La) was measured in the temperature range from 298 to 1473 K. The coefficients of thermal expansion (CTE) were determined by differentiating the thermal expansion expressed by a polynominal equation of temperature with respect to temperature. The CTE (α1) for Ce0.8R0.2O1.9 was in the range from 10×10-6 to 14×10-6K-1 and increased nonlinearly with increasing temperature. This result was explained by the asymmetric curve of potential energy based on the lattice energy theory. The kinds of dopant gave small effect on the α1 of rare-earth-doped ceria. On the other hand, the average CTE for CeO2 and rare-earth-doped ceria (12.0-12.5×10-6K-1), determined from a linear approximation of thermal expansion with respect to temperature at 298-1273 K, was lower than the α1 and close to the previously reported values.