Entity

Time filter

Source Type


Obata S.,Gifu Prefectural Ceramics Research Institute | Kawai S.,Gifu University | Yoshida M.,Gifu University | Sakurada O.,Gifu University | Kido K.,Kawai Lime Industry Co.
Ceramic Transactions | Year: 2014

It was discussed that flaked shaped particle with nano sized ceria (CeO2) or zinc oxide (ZnO) synthesized by wetting process was possible to use as UV adsorption materials. Titanate aqueous solution (TNB-Lac) prepared by direct reaction of titanium tetra-n-butoxide (TNB) with lactic acid (Lac) in water shows characteristics of a polyanion and acts as a dispersant for preparing aqueous CeO2 slurries. The isoelectric point (IEP) of CeO2 particles shifted to lower pH with increasing concentration of TNB-Lac. Well-diesperesd CeO2 slurries were obtained by modification of the surface changes on CeO2 to adjust pH and addition of TNB-Lac concentration. On the other hand, the IEP of boehmite particles was at around pH 9.5. According to this result, the boehmite/CeO2 or boehmite/ZnO pomposities could be synthesized by the electrostatic attraction between positively charged boehmite substrate and negatively charged CeO2 or ZnO nanoparticles with 0.1 mmol/g TNB-Lac at around pH between 6 to 7. The synthesized particles were characterized by spectrophotometer and scanning electron microscopy. With boehmite/CeO2 or boehmite/ZnO volume ratio 80/20, the boehmite was covered with CeO2 or ZnO nanoparticles by microstructural observation. The silicon resin film including 5 mass% the synthesized composite with 20 vol% CeO2 gave the equivalent UV shield ability, compared with the property of the film including nano-sized CeO 2. Source


Hayashi A.,Gifu Prefectural Ceramics Research Institute | Hayashi A.,Nagoya Institute of Technology | Adachi N.,Nagoya Institute of Technology | Ota T.,Nagoya Institute of Technology | And 3 more authors.
Proceedings UNITECR 2011 Congress: 12th Biennial Worldwide Conference on Refractories - Refractories-Technology to Sustain the Global Environment | Year: 2011

The absorbed energy of aluminium titanate (Al2TiO5) refractory ceramics was measured with a pendulum-style impact test machine. Aluminium titanate ceramics are well-known as low thermal expansion materials and high thermal shock resistance materials. We prepared some aluminium titanate ceramics which had low elastic modulus of 0.1-11GPa and therefore showed a flexibility, the absorbed energy increased with increasing flexibility. Source


Ishizawa N.,Nagoya Institute of Technology | Tateishi K.,Gifu Prefectural Ceramics Research Institute | Oishi S.,Shinshu University | Kishimoto S.,High Energy Accelerator Research Organization
American Mineralogist | Year: 2014

Single-crystal synchrotron X-ray diffraction experiments are conducted on spinel-type LiMn2O4at 230 and 320 K to investigate the effect of charge disproportionation of Mn ions on phase transition near room temperature. The orthorhombic 3ac× 3ac× 1acsuperstructure of the low-temperature form, where "ac" is the ideal cubic cell edge, has a network of Mn4+ions at the vertices of a slightly distorted truncated square tessellation comprising one square and two octagonal prisms; the square prism and one type of octagonal prism house Mn3+ions with Jahn-Teller (JT) elongated Mn-O bonds almost parallel to the c and b axes, respectively, whereas the other octagonal prism houses Mn ions with JT-induced bond-length fluctuation for the Mn-O bonds lying almost parallel to the a axis. The Mn ions in the latter octagonal prism are assumed to exchange their oxidation states dynamically between 3+ and 4+ in a time ratio of-3:1, forming a polaron centered at a Mn4O4heterocubane cluster with orbital and spin orders. The high-temperature cubic form contains an inherent positional disordering of oxygen ions. The effect of the molecular polarons on the phase transition mechanism is discussed on the basis of a spin blockade in the form of truncated square tessellation. © 2014 by Walter de Gruyter Berlin/Boston. Source


Hayashi A.,Gifu Prefectural Ceramics Research Institute | Tsuge H.,Gifu Prefectural Government | Kurachi K.,Gifu Prefectural Ceramics Research Institute | Mizuno M.,Gifu Prefectural Ceramics Research Institute | Ota T.,Nagoya Institute of Technology
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2012

The impact strengths of strengthened porcelain bowls were evaluated using an impact examination machine based on JIS S 2402. A strain waveform developed upon impact was measured by a strain gauge adhered to the inside surface on the porcelain bowl. The deformation of the porcelain bowls was observed by high-speed camera. The strain waveforms showed two noteworthy peaks. The first peak was found to be caused by the initial impact, and the second peak was found to be caused by the restorative force generated by the deformation of bowl, which acted as a backstop. The high-speed camera also revealed that the bowl re-collided with the hammer or pushed the hammer again as the bowl returned to its original shape and position, resulting in the second peak. The variation of the strain waveform was found to be related to the size of bowl and the open angle of the backstop. © 2012 The Ceramic Society of Japan. All rights reserved. Source


Obata S.,Gifu Prefectural Ceramics Research Institute | Iwata Y.,Gifu Prefectural Ceramics Research Institute | Yokoyama H.,Gifu Prefectural Ceramics Research Institute | Sakurada O.,Gifu University | And 2 more authors.
Ceramic Transactions | Year: 2010

A water soluble titanate compound (TNB Lac) prepared by direct reaction of titanium tetra n butoxide (TNB) with lactic acid (Lac) in water showed characteristics of a polyanion and acted as a dispersant for preparing aqueous aluminum titanate (Al 2TiO 5) slurries. The isoelectric point of Al 2TiO 3 particles shifted to lower pH with increasing concentration of TNB Lac. The rheological behavior of aqueous Al 2TiO 5 slurries with TNB Lac was examined and evaluated. The dispersion and fluidity of aqueous Al 2TiO 5 slurry were enhanced by the addition of TNB Lac at pH 10, and the thickening limit of the well dispersed and fluidized slurry with 0.075 mmol g 1 TNB Lac was found at a solid content of 79 wt%. A high green density of 63% for the sintered powder was obtained through the slip casting process using slurries with 0.075 mmol g 1 TNB Lac. The maximum relative density value of the sintered bodies was 96.5% when the green body was fired at 1500°C. The sintered body had a homogeneous grain growth and dense microstructure without pores or abnormal grain growth. Source

Discover hidden collaborations