All issues
Volume 51, Issue 3
Special Issue of 49th Summer Symposium
Displaying 1-12 of 12 articles from this issue
- |<
- <
- 1
- >
- >|
Original Paper
-
Tatsumi Yamamoto, Hiroyuki Kawasaki, Mitsukuni Mizuno, Hidetoshi Mori2014 Volume 51 Issue 3 Pages 124-130
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSAn ultrasound (US) irradiation technique was applied to obtain the rod-like L-aspartic acid crystal in cooling crystallization process. In experiments, the 20 kHz horn-type transducer was installed vertically into the aqueous solution. Experimental results confirmed that arithmetic mean and ratio of breadth and length of a formed crystal can be reasonably controlled by US intensity and irradiation time. The high yield of rod-like crystals was obtained under the conditions of 46 W/cm2 US intensity and 1 min irradiation time. SEM and XRD analysis demonstrated that all crystals formed in this study were plate like α-form, and that rod-like crystals formed by US irradiation were revealed to be the polysynthetic twin composed of small size plate-like crystals.View full abstractDownload PDF (699K) -
Eri Nakamura, Akira Kondo, Takahiro Kozawa, Hiroya Abe, Makio Naito, J ...2014 Volume 51 Issue 3 Pages 131-135
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSBy using the one-pot mechanical method，the layered rock-salt LiCoO2 powder was synthesized from Li2O and Co3O4 starting powders without any extra heat assistance. Processing time was only 15 min. The synthesized powders had the granule structure composed of primary nanoparticles. The solid-state synthesis of LiCoO2 from the same starting materials was also performed for comparison of powder properties. The calcination temperature to obtain LiCoO2 in the single phase was over 500℃ for 2 h. The BET equivalent diameters of the mechanically synthesized LiCoO2 powders was about 120 nm，which was close to that of the particles synthesized by solid-state reaction at 500℃.View full abstractDownload PDF (952K) -
Shiho Suehiro, Hiromi Nakano2014 Volume 51 Issue 3 Pages 136-141
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSIn the ternary Li2O-M2O5-TiO2 （M＝Ta, Nb） system, a superstructure is formed in the chemical formula of Li1+x-yM1-x-3yTix+4yO3 (0.06<x<0.33, 0<y<0.175), which is the so-called M-phase. In the Ta-system, the superstructure was found to form with higher Ti content (0.06<x<0.2, 0.05<y<0.175). In this paper, we focus on the difference between Ta and Nb ions in the formation of a superstructure in the quaternary system Li1+x (Ta1-zNbz)1-xTixO3 (0.11<x<0.33, 0<z<1.0). The structural change is observed through the grain morphology, X-ray diffraction pattern, and transmission electron microscope image. The results show that the period of the intergrowth layer in the superstructure could be controlled with the Ti content and Ta/Nb ratio.View full abstractDownload PDF (771K) -
Mitsuru Tanahashi, Tatsuya Tomida, Akihide Nagasaka, Kazuki Asai2014 Volume 51 Issue 3 Pages 142-152
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSThe authors have investigated a pre-control of loosely agglomerated structure of silica nanoparticles as filler component used for the fabrication of organic/inorganic nanocomposites by a blending method. The packing structure and void fraction of the agglomerate of silica nanoparticles that affect a dispersibility of their particles in polymer matrix were controlled by destabilizing a nano-sized silica sol via pH control and salt addition. It was found that three dimensional networks of nano-silica are formed in the pH-controlled sol due to a silica-silica bridging through coordination with flocculating cations of added salt. As another role of the added salt, its crystal seemed to act as a template that enlarges void spaces inside the silica network as the solvent evaporation progresses. The silica agglomerate with the highest void fraction (～0.49) could be prepared by controlling pH of sol （≧4） and the ratio of volume of added salt to that of colloidal silica (≧1/9) under the present experimental conditions.View full abstractDownload PDF (1525K) -
Kouichi Yasuda, Satoshi Tanaka, Makio Naito2014 Volume 51 Issue 3 Pages 153-162
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSA multiple shell model was proposed to explain homogenization process in ceramic powder compact during repeated isostatic pressing. The multiple shell model was composed of n-concentric thin shells and each shell had its own relative density and Young's modulus. When a cold isostatic pressure was applied to the model from the outside, simultaneous equations for pressures in the shells were obtained so as to match the displacement between adjacent shells. The stress distribution in the model was obtained by solving these equations, and then the relative density and Youngs modulus of each shell was updated to correspond its own stress distribution. By repeating this calculation, the change in the relative density was obtained under repeated isostatic pressing. The calculation showed that repeated isostatic pressing was effective to homogenization of ceramic powder compact, compared with applying high isostatic pressure once.View full abstractDownload PDF (803K) -
Kimitoshi Sato, Hiroto Hirano, Tohru Suzuki, Takamasa Ishigaki, Yoshio ...2014 Volume 51 Issue 3 Pages 163-168
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSPlate-like Ti3SiC2 particles were prepared. Highly textured and dense Ti3SiC2 ceramics was successfully fabricated by slip casting plate-like particles in a strong magnetic field followed by pulsed electric current sintering at 1450℃under 80 MPa for 5min. 3 point bending strength and K1C of the textured Ti3SiC2 ceramics were 812 MPa, 7.3 MPa・m1/2, respectively. Compared to the Ti3SiC2 ceramics prepared by slip casting without magnetic field, the 3 point bending strength and K1C of the textured Ti3SiC2 ceramics have been increased by factors of 1.05 and 1.22, respectively.View full abstractDownload PDF (812K)
Short Communication
-
Kazuya Horiguchi, Kazuyoshi Sato,, Takayuki Takarada2014 Volume 51 Issue 3 Pages 169-173
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL FREE ACCESSTar reforming property was investigated for BaSnO3 catalysts with plate-like and spherical morphologies synthesized through heat treatment of co-precipitation derived BaSn(OH)6 and BaCO3/SnO2 nanocomposite precursors, respectively. The reforming test was performed at 750℃ for 3h using thermogravimetric analyzer with toluene as a model tar. Plate-like BaSnO3 showed higher catalytic activity than spherical one due to not only higher specific surface area but also exposed active crystal facets. The reforming property and coking resistance were significantly promoted under the presence of steam due to continuous release of active oxygen species from the lattice and recovery of them from the environmental steam.View full abstractDownload PDF (602K)
Review
-
Makio Naito, Hiroya Abe, Akira Kondo, Takahiro Kozawa2014 Volume 51 Issue 3 Pages 174-184
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL RESTRICTED ACCESSStructure control of particles and powders are key issues for developing advanced materials. In this paper, manufacturing process of advanced ceramics using raw powder materials is discussed to make clear the role of powder structure control for high quality materials. On the other hand, particle structure control is also very important to develop functional particles and the advanced materials by assembling them. In this paper, processing technology of composite particles is also introduced to explain their roles for developing advanced materials including lithium ion batteries, fuel cells and thermal insulation materials.View full abstractDownload PDF (1303K) -
Satoshi Tanaka, Keizo Uematsu2014 Volume 51 Issue 3 Pages 185-191
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL RESTRICTED ACCESSVariation of mechanical property for advanced ceramics is one of the serious problems. We have developed the various optical methods to examine the macro defects in ceramics before and after sintering. There are lots of crack-like macro-defects in ceramics. Their origins of macro defects were formed even after compaction of granules. The macro defects in ceramics successfully explained the strength variation by strength test simulation based on defects distribution. Micro x-ray computer tomography has been developed as a powerful tool for measurement of macro-defects, recently. Their image will show us 3 dimensional structures for various materials.View full abstractDownload PDF (1323K) -
Yuta Mochigi, Shigeki Aoyagi, Nahito Kawaguchi, Motohiro Kawai, Takayu ...2014 Volume 51 Issue 3 Pages 192-199
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL RESTRICTED ACCESSTerahertz time-domain spectroscopy (THz-TDS) is a technology which is expected as a new PAT tool in the pharmaceutical field. It is safe because energy is low, and it can be used to analyze the state of material inside without breaking. We conducted two experiments using THz-TDS. One was a component analysis by transmittance spectrum, and the other was coating thickness measurement. These experiments were qualitatively assessed which components of the mixed granules, and also estimated the thickness of the coating. These results showed the potentially can be used THz-TDS as PAT tool.View full abstractDownload PDF (845K)
Technical Note
-
Shuji Sasabe, Kenji Shimizu2014 Volume 51 Issue 3 Pages 200-205
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL RESTRICTED ACCESSPowder technology has relations to almost all industries. Recently, demands of materials/ intermediate products of ultra-fine powder increase, of which handling is difficult and on the other hand strict managements of the quality of powder materials are required. In order to confirm applications of these materials to performance of products, it is necessary to measure properties of materials reproducibly without personal errors. In this paper, instruments to evaluate powder characteristics are explained.View full abstractDownload PDF (693K) -
Yukiko Fujita, Kazunori Fukumoto, Hajime Agata, Takehisa Fukui2014 Volume 51 Issue 3 Pages 206-211
Published: March 10, 2014
Released on J-STAGE: April 05, 2014
JOURNAL RESTRICTED ACCESSThe continuous kneading process using the twin shaft kneader has had been development for future mass production. We studied condition for continuous kneading, and the paddle arrangement in the kneader and dosing pattern of binder solution were discussed.
Lithium cobaltite was chosen as a cathode active material. The slurries were prepared by the continuous kneading and these obtained slurries were evaluated viscosity characteristics and dispersion of the electrode materials. The battery performance of coin type cell using these obtained slurries was also evaluated.
The experiments showed that the paddle arrangement and dosing pattern of binder solution influenced viscosity and battery performance, and the continuous kneading process can produce preferable properties of electrode slurry.View full abstractDownload PDF (668K)
- |<
- <
- 1
- >
- >|