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Volume 48, Issue 3
Displaying 1-15 of 15 articles from this issue
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Yoshikazu Suzuki, Katsuyosi Shimokawa, Hideki Minagawa2001 Volume 48 Issue 3 Pages 209-213
Published: March 15, 2001
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSTo improve the property of Cu-SMA (shape memory alloy) system in a cold district, molten alloy was produced by means of SHS method. It was determined that the shape memory behavior of the Cu-Al-Ni alloy, which was added to other elements in the base of the alloy, showed a different behavior than the base alloy.
The following results were obtained.
(1) A uniform Cu based shape memory alloy was prepared by use of exothermic reaction of Cu-Al-Ni.
(2) By the elemental addition of B or the mixture of B and C to a Cu-Al-Ni-Ti alloys, the reversible curve of shape memory behavior was improved in the lower temperature than 0 °C.
(3) A molten Cu-Al-Ni alloy formed in the uniform structure improved in performance in terms of the fracture strength and the deformed ratio.View full abstractDownload PDF (5794K) -
[in Japanese]2001 Volume 48 Issue 3 Pages 216
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (72K) -
Yukio Higuchi, Hiroshi Tamura2001 Volume 48 Issue 3 Pages 217-221
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSSince the 1970's, dielectric resonator materials have been developed and put into practical use for filters and oscillators in microwave frequency, miniaturizing these components and saving costs. The concentrated effort has been undertaken to decrease the dielectric loss of these materials. In this paper, the recent progress on the dielectric properties of dielectric resonator materials is reported with their practical applications. The dielectric materials suitable for each application such as the antenna duplexer for.handymobile phone, the filter for cellular base station, millimeter-wave application and high temperature superconductor are introduced with their dielectric properties.View full abstractDownload PDF (1538K) -
Takeshi Nomura2001 Volume 48 Issue 3 Pages 222-232
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe aim of this paper is to focus on the development in the field of electronic ceramic materials, such as MnZn ferrites, multilayer ferrite chip components, and base metal electrode multilayer ceramic capacitors. There are many requirements for electronic ceramics, among which the reliability and low loss characteristics are of prime importance. New material technologies for ensuring high performance ferrites and highly reliable multilayer chip components are shown with special reference to the microstructure. For achieving high performance ferrite cores, adequate additives and control of nonstoichiometric oxygen content by firing conditions are quite important. Material technology for multilayer ferrite chip components are described with special reference to the behavior of silver during firing. Also, highly reliable multilayer ceramic capacitors with Ni electrodes have been developed by controlling chemical composition and grain boundary chemistry.View full abstractDownload PDF (6980K) -
Yukie Nakano, Tamami Kato, Takeshi Nomura2001 Volume 48 Issue 3 Pages 233-236
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effect of the producing process on the mechanical property of multilayer ceramic capacitors (MLCs) has been studied. It is shown that the barrel finishing before termination made mechanical deterioration on MLCs, and the heat treatment after barrel finishing made recovered that. The X-ray diffraction profiles of MLCs surface were broadened and shifted to lower angle side after barrel finishing, and that was recovered after heat treatment. Besides only one side of MLCs finishing made deterioration of mechanical property. Therefore these deteriorations were attributed to the internal stress at inner part of MLCs.View full abstractDownload PDF (3984K) -
Toshikazu Sugimura, Yoshiyuki Tanaka, Masahiko Mizukami, Masahiro Kato ...2001 Volume 48 Issue 3 Pages 237-243
Published: March 15, 2001
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSLow temperature operating cathodes produced by hot isostatic pressing (HIP) have been developed. This new cathode, which has the advantages of both oxide cathodes and dispenser cathodes, was achieved by HIP, although sintered cathodes have not been successful thus far. Nickel powder and Ba-Sr-Ca carbonate (emitter) powder are mixed, pressed and subsequently encapsulated into a glass capsule under vacuum. HIP was performed at 1373 K and 130 MPa. The carbonate emitter was converted into oxide by heat treatment in a cathode ray tube. The optimized operating temperature of the HIP cathode was 1053 K, which was almost the same as that of oxide cathodes and was 150 K lower than that of dispenser cathodes. The life test of the HIP cathodes revealed only less than 10% decay after 30000 h under a high current density of 3 A/cm2. In contrast, oxide cathodes showed about 50% decay after only 1000 h under the same current density.View full abstractDownload PDF (3760K) -
[in Japanese]2001 Volume 48 Issue 3 Pages 246
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
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Takashi Yamada, Kazunori Adachi, Tatsumi Ishihara, Yusaku Takita2001 Volume 48 Issue 3 Pages 247-250
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSWe have been developing a planar type Solid Oxide Fuel Cell (SOFC) using LaGaO3-based oxide as an electrolyte in order to lower the operating temperature. A large power density higher than 350 mW/cm2 at 650°C was achieved by adoption of 230μm thickness La0.8Sr0.2Ga0.8Mg0.15Co0.05O3-σ (LSGMC) for the electrolyte so far. In this study, Effects of oxide doping into LaGaO3-based solid electrolyte on the mechanical property has been investigated in detail. It was found that doping of several kind of oxides is effective for improving the mechanical strength. In particular, MgO doped LSGMC maintained power generation performance while the mechanical property was improved. The SEM observations of the sintered samples revealed that the matrix grains were significantry smaller than "plain" LSGMC and MgO particles dispersed alway matrix grains boundaries.View full abstractDownload PDF (2905K) -
Synthesis and Electrical Property of Novel Compound, KxCax/2Sn8-x/2O16(X≤2) with Hollandite StrutureMitsuru Honda, Jun Sakuma, Kyota Uheda, Hirotsugu Takizawa, Tadashi En ...2001 Volume 48 Issue 3 Pages 251-253
Published: March 15, 2001
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSA new tin oxide, KxCax/2Sn8-x/2O16 (x≤2) with the hollandite type structure was synthesized at 973 K-1473 K in air by a conventional ceramic process. Its structure was classified as monoclinic symmetry with the lattice parameters of a=1.5006(1)nm, b=0.32108(1)nm, c=1.0608(1)nmand, β=134.954(6)°. The well-grown fibrous aggregation was observed in the melted K2CO3. Its electrical conductivity and activation energy were estimated to be about 2.2 × 10-9 Ω-1·m-1 (room temperature) and 0.63 eV. Accordingly, the ionic conduction was substantially governed by the migration of ions from site to site in the tunnel.View full abstractDownload PDF (1543K) -
Keijiro Terashita, Hideya Asano, Kei Miyanami2001 Volume 48 Issue 3 Pages 254-259
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn the present study, the methods for evaluating the dispersion of positive electrode materials for Lithium ion secondary battery were examined and the operations of wet dispersion were conducted to prepare the plate which is superior in electrical resistance. First, particle size distribution and viscosity of pastes were measured. Subsequently, the coated film was prepared on the plate using the pastes and glossiness and electrical resistance of the plate were measured.
It was reconfirmed in the study that the dispersion of positive electrode materials could be evaluated by measuring glossiness and electrical resistance of coated film on the plate. It was also pointed out that glossiness and electrical resistance could be inferred by particle diameter, D10.
Glossiness and density of coated film showed large values by high-dispersing the paste of positive electrode materials for that to have small particle size. That meant that the plate could be prepared which is superior in electrical resistance.
The preparation of pastes is extremely important to pack tightly particles for positive electrode on the plate. It was implied that the wet dispersion of particles for positive electrode determined battery characteristics.View full abstractDownload PDF (563K) -
Highly Densed-MH Electrode Using Flaky Metal Powder and Gas-atomized Hydrogen Absorbing Alloy PowderHiroshi Yoshinaga, Yoshiro Arami, Osamu Kajita, Tetsuo Sakai2001 Volume 48 Issue 3 Pages 260-266
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSGas-atomizing method was used to fabricate sphere-shaped hydrogen storage alloy powder (AB5 type alloy). The alloy powder was intermixed with flake-shapes Ni powder, followed by pressure-molding to make electrode. Charge/ discharge cycle test was conducted at current density of 100A/kg. The spherical alloy powder was packed densely into the electrode, achieving a maximum capacity per volume of electrode of 1800 Ah/L. The shape effect of the nickel powder and hydrogen storage alloy powder was discussed.View full abstractDownload PDF (5802K) -
Ryo Tamori, Nobuya Machida, Toshihiko Shigematsu2001 Volume 48 Issue 3 Pages 267-273
Published: March 15, 2001
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSMeta-stable phase Li4.4Si was prepared by mechanical milling process. In order to investigate the electrochemical properties of the meta-stable Li4.4si, two types of electrochemical cells were used; one of them was three-electrode cell with usual liquid electrolyte LiPF6-EC/DMC, and the other was all solid state cell with solid electrolyte a-60Li2S⋅40SiS2, which was also prepared by mechanical milling process and showed high Li+ ion conductivity of 1.8×10-4 Scm-1 at room temperature. Electrochemical capacity of the meta-stable Li4.4Si was about 400 mAhg-1 for Li+ ion extraction in the liquid electrolyte. The capacity was decreased with an increase in the number of Li+ extraction-insertion cycles. The Li+ extraction and insertion from the meta-stable Li4.4Si brought about the reaction between the Li4.4Si sample and metallic Cu, which was used as a collector of electronic current. Electrochemical extraction of Li+ ions from the meta-stable phase showed the capacity exceeding 250mAhg-1 for the all-solid state cell using the solid electrolyte and TiS2 as counter electrode. In this solid state cell, the meta-stable phase showed almost no structural change during the extraction and insertion of Li+ ions.View full abstractDownload PDF (611K) -
Yoshinori Arachi, Takeshi Asai, Michinori Nagai, Yuichi Katoh, Mitsuha ...2001 Volume 48 Issue 3 Pages 274-277
Published: March 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe substitution of Li+ for Zn2+ and Ti4+ for Fe3+ in ZnFe2O4 with the spinel stype structure was adopted to obtain the fundamental understanding of the Li ion conduction in solids. The cation distribution of the compound was investigated at the starting research. The XRD patterns indicated the formation of the solid solution, Zn1-xLixFe2-xTixO4 and the lattice parameter decreased linearly with the increase of x in accordance with the ionic radius for each cation. Above x = 0.6 a slight curvature appeared in the composition dependence of the lattice parameter. The Rietveld analysis determined the cation distribution for the present system. It can be written as Zn1-xFex[8a][Lix/2Fe1-xTix/2][16d]2O4 (for x <0.5). It showed that Li+ occupies the octahedral (16d)site, whereas Fe3+ occurs on the tetrahedral (8a) site. Li+ had a preference for 16d sites up to x = 0.5. On the other hand, Li+ starts out going to the tetrahedral site above a concentration of 0.5. The cation distribution can be written as Zn1-xFe0.5Lix-0.5[8a][Li0.25Fe(1.5-x)2Tix/2][16d]224 (for x> 0.5). The observed change in the composition dependence of the lattice parameter is caused by the change of the cation distribution in the spinel structure. In addition, the iron distribution for the present system was confirmed by the Mossbauer spectroscopy. The electrochemical lithium insertion was also discussed.View full abstractDownload PDF (292K) -
Takeshi Sakurai, Takashi Kimura, Tadashi Sugihara2001 Volume 48 Issue 3 Pages 278-282
Published: March 15, 2001
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSThe orthorhombic LiMn0.95-xCr0.05MxO2 Compounds, (M=Al, Ga, In, Yb, Y; x= 0-0.07) were synthesized by a hydrothermal technique and their electrochemical capacity and capacity retention were measured. The nominal composition of LiMn0.92Cr0.05M0.03O2 showed the most improved cycle performance, which exhibited high capacity up to 150 mAh/g until 80 charge-discharge cycles. TEM observations using (110) diffraction spot revealed stacking fault existing in grains of the improved samples. No stacking fault was observed in other samples exhibiting poor cycle performance. The introduction of stacking faults into grains seems to be occurred in a certain range of average ionic radius at cation sites, which was realized in the element combinations of (Cr, In) and (Cr, Yb). The improved samples showed Li-poor composition comparing to nominal compositions. On the other hand, samples exhibiting poor cycle performances showed Li-rich compositions. X.R.D. measurements showed that phase transformation from orthorhombic structure to spinel type structure occurred even in the LiMn0.92Cr0.05M0.03O2 sample during the cycles. It can be concluded that the three factors, introducing stacking faults into grains, controlling stoichiometry of the sample and blocking the phase tranformation are key parameters for improving the cycle performance.View full abstractDownload PDF (2208K) -
Kiyoshi Kanamura, Wataru Hoshikawa, Takao Umegaki2001 Volume 48 Issue 3 Pages 283-287
Published: March 15, 2001
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSLiMe1/6Ni2/6Mn9/6O4(Me=Cr, Fe, Co, Ni, Cu, Zn) were prepared and tested as 5V cathode materials. When using Ti mesh current collector, these cathode materials did not exhibit a good performance, due to a corrosion of Ti mesh current collector. On the other hand, the LiMe1/6Ni2/6Mn9/6O4 materials showed the excellent rechargeability and relatively high discharge capacity when using Al current collector. The discharge capacity and rechargeability of LiMe1/6Ni2/6Mn9/6O4 strongly depended on the kind of the substituted ions. The best performance was obtained when a part of Mn ions in LiMn2O4 crystal was substituted by Ni ions (LiNi0.5Mn1.5O4). The discharge capacity was more than 130 mA h g-1 and the rechargeability was 100%. The coulombic efficiency was about 97 %. The average discharge potential was 4.75 V vs. Li/Li+.View full abstractDownload PDF (1987K)
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