巻号一覧
50 巻, 12 号
選択された号の論文の14件中1～14を表示しています
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新庄 輝也2003 年 50 巻 12 号 p. 1015-1021
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーStudies on artificially structured multilayers by the author's group for about 20 years are briefly surveyed. In many combinations of metallic elements, establishment of nanoscale superstructures has been confirmed, which suggests the potensial to create new materials. The novel phenomenon, giant magnetoresistance (GMR), was found first in Fe/Cr multilayers and the technical application of the GMR principle has been successfully realized as the spin-valve recording head. Perspectives for further studies on magnetic multilayers are also mentioned.抄録全体を表示PDF形式でダウンロード (684K) -
桜井 法昭, 武川 淳二郎2003 年 50 巻 12 号 p. 1025-1030
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーTitanium foams having higher porosity were fabricated by a powder metallurgical process using the slurry. Titanium powder was dipped to the solution of 7.5 mass% polyvinyl alcohol, and stirred to make the slurry. The slurry was lightly compacted and blown up under the diminished pressure. The foamed compacts were debound in vacuum at 723 K and sintered at 1373 K in vacuum. It was shown that the porosities and the pore sizes of the sintered titanium foams increased with decreasing the atmospheric pressure and the maximum porosity of 80% was obtained at the pressure of 80hPa. The plateau regions on the stress-strain curves were clearly observed for the titanium foams in compression test. The titanium foams having porosity of greater than 75% showed the similar properties with other metal foams. Because of their unique characteristics, these materials would be applicable to shock absorbers, filters and biomaterials.抄録全体を表示PDF形式でダウンロード (3599K) -
多田 吉宏, 山口 健次2003 年 50 巻 12 号 p. 1031-1035
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーIn the powder metallurgical process to produce foamed cellular aluminum, relative densities and foamabilities of hot pressed or powder forged preforms have been investigated to find out more suitable consolidation techniques compared with hot extrusion for small-and medium-sized productions. Coarser aluminum powder suited to achieve highly expanded foams for the present processes. Regardless of the examined two consolidation processes, the preforms with relative density over 0.97 were able to expand into foams with 60 to 70% porosity. However, it was important to apply a fixed consolidation condition in.order to obtain foams with stable porosity. Both hot pressed preforms and powder forged ones showed basically the same foamabilities as those of hot extruded preforms, except for the fact that 20 K and 50 K higher foaming temperatures were suitable for the hot pressed preforms and the powder forged ones, respectively.抄録全体を表示PDF形式でダウンロード (2177K) -
皆川 和己, 垣澤 英樹, 太田口 稔, 大澤 嘉昭, 高森 晋, 原田 幸明2003 年 50 巻 12 号 p. 1036-1040
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (5291K) -
田中 利一2003 年 50 巻 12 号 p. 1041-1044
発行日: 2003/12/15
公開日: 2009/12/04
ジャーナル フリーThe magnetization and Curie temperature of sputter-deposited MnZn ferrite thin films are examined. As-deposited films at room temperature and 300°C are crystalline and have a spinel structure. However, their saturation magnetization is smaller and their Curie temperatures are higher than those of heat-treated films at 800°C-900°C. The results are explained by assuming that the ion distribution in the as-deposited films is in nonequilibrium: Some of the Zn ions and Mn ions occupying the A sites in equilibrium occupy the B sites, and the same number of Fe ions transfer to the A sites. Moreover, in the films heat-treated at 800°C-900°C, the saturation magnetization decreases and the Curie temperature rises with a rise in the heat treatment temperature. These are also explained on the basis of a variation in the equilibrium ion distribution with the heat treatment temperature.抄録全体を表示PDF形式でダウンロード (294K) -
Tasaburo Saji, Yukio Makino, Shoji Miyake2003 年 50 巻 12 号 p. 1045-1051
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーA densification temperature of a ceramic material by microwave sintering is quite lower than the temperature by conventional sintering. However, the ceramic material is self-heated by electromagnetic energy during the microwave sintering processing, so that possibility of temperature measuring error is considerably high. Then it is difficult to prove that the densification temperature by microwave sintering is lower than the temperature by conventional sintering.
There is a problem of sintering Si3N4 that sintering temperature is higher than decomposition temperature in atmospheric pressure of N2 gas, and a specimen can not be high density if a powder bed is not used. The decomposition rate becomes fast at the densification temperature. Furthermore, sintering density is lowered with the rise of sintering temperature since the decomposition rate becomes faster. Because of that, Si3N4 is sintered in high pressure N2 gas, or in atmospheric pressure of N2 gas with powder bed.
When a Si3N4 specimen which included 5 w% Al2O3 and 5 w% Y2O3 as sintering aids, was sintered at 1700°C by conventional heating in atmospheric pressure of N2 gas without powder bed, sintering density reached 88%. And the density is lowered when the heating temperature was higher than 1700°C. The density more than 88% was not obtained even the sintering temperature was higher.
On the other hand, when the specimen was sintered by microwave treating in atmospheric pressure of N2 gas at 1600V without powder bed, the sintering density was 98.1% and 98.7% at 1650°C and reached 99.0% at 1700°C.
This shows clearly that the densification temperature by microwave sintering is lower than decomposition temperature. In other words, this shows that the densification temperature by microwave sintering is lower than the temperature by conventional sintering.抄録全体を表示PDF形式でダウンロード (561K) -
川村 悟史, 桑野 寿, 武田 裕基, 高橋 志郎, 加賀 寿2003 年 50 巻 12 号 p. 1052-1056
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーNanocrystalline iron powders with grain size of 13nm were prepared by ball-milling. The nano-structured iron powders were consolidated into discs with a diameter of 30 or 50 mm by Spark Plasma Sintering at 550°C under pressures between 80 to 220 MPa. The average grain size of the consolidated discs is about 80 nm. It does not depend on the sintering time at constant pressure. The Vickers hardness of the superfine grained iron sintered for 600 s with 220 MPa is 470 Hv. The value is plotted on the linearly extrapolated line of the Hall-Petch relationship obtained by Malow and Koch in the study on the grain size smaller than 40 nm.抄録全体を表示PDF形式でダウンロード (1513K) -
青銅系圧粉体の焼結緻密化におよぼすV添加の影響加藤 和夫, 森川 満隆, 田上 道弘, 山田 眞二, 武田 徹2003 年 50 巻 12 号 p. 1057-1061
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーIn the previous paper, we reported the densification of the bronze matrix was promoted by the diffusion of Cr under solid state sintering at 1030 K. In the present work, effects of V addition on sintering properties and microstructures of the bronze matrix were investigated, and compared with Cr. Mixed powders were prepared from pulverized V powders and atomized 90Cu-10Sn powders, of which particle sizes were 106-150μm and 1-38μm respectively. Compacts pressed at 390 MPa were sintered at 670-1030 K for 0.3-180 ks in H2. V diffuses preferentially into the surface and grain boundary of the bronze powder. With increasing sintering time at 1030 K, pores of matrix decrease rapidly. This indicates that the densification of the bronze is promoted by the diffusion of V as same as the case of Cr. However, some pores are observed on the matrix and the grain size is bigger than the case of Cr after 180ks sintering at 1030 K. From these results, it is assumed the effects of densification by V addition is slightly smaller than Cr.抄録全体を表示PDF形式でダウンロード (5526K) -
浅岡 裕史, 草野 圭弘, 中西 真, 藤井 達生, 高田 潤2003 年 50 巻 12 号 p. 1062-1067
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーHuman beings have been using "bengara" (α-Fe2O3) as red pigment ever since ancient times. As for Japan, the first artificial "bengara" was manufactured at Fukiya town in 1707, and it was mainly used for red painting of porcelain and other objects for about 300 years. However this "Fukiya bengara" cannot be manufactured anymore because of the environment pollution in spite of eagerness of potters to use it for producing bright yellowish red. At first step, we characterized traditional "Fukiya bengara" and found that α-Al2O3 existed. It is probably due to the formation of Al substituted α-Fe2O3. Then next step, we prepared red pigment of Fe2O3-Al2O3 system to investigate the Al substitution effect, by using both solid-state and polymerized complex methods. The red tone color depended on the particle size; the yellowish red pigment had the smallest size. Al substitution seemed to suppress the grain growth of hematite. The red tone color was controllable with the amount of Al substitution. α-(Fe0.9Al0.1)2O3 prepared at 1000°C for 2 hours presented as bright yellowish red color as that of "Fukiya Bengara".抄録全体を表示PDF形式でダウンロード (6923K) -
武田 保雄2003 年 50 巻 12 号 p. 1070
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (102K) -
雨澤 浩史, 西川 義人, 冨井 洋一, 山本 直一2003 年 50 巻 12 号 p. 1071-1078
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーThe spark plasma sintering (SPS) method was employed to prepare sintered specimens of proton conducting Sr-doped LaPO4 ceramics. The relative densities of the sintered Sr-doped LaPO4 were around 99% when higher sintering temperatures than 1050°C were applied for the SPS process, while only 93% of relative density was achieved with the conventional pressure-less sintering (PLS) method at 1200°C. Electrical conduction properties of the sintered samples with the SPS method at 1200°C were evaluated by using conductivity measurements at 500-930°C under 0.4-5kPa of p(H2O) or p(D2O) and 0.01-100kPa of p(O2). The specimen prepared with the SPS method showed similar conductivities and conduction properties as that prepared with the PLS method. These results suggested that the SPS method was a useful sintering technique to prepare proton conducting phosphate-based ceramics with a high density while keeping a feature of protonic conduction.抄録全体を表示PDF形式でダウンロード (6010K) -
Toru Hatae, Yohtaro Yamazaki2003 年 50 巻 12 号 p. 1079-1083
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーPreparation of the thin film La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) on a porous La0.7Sr0.3MnO3 (LSM) substrate using the sol-gel method was investigated. At first, a stable precursor solution was prepared. Then the thin films were prepared from the solution by spin coating on a porous LSM substrate filled with ethylene glycol. The phase of the obtained films was confirmed by X-ray diffraction. Main phase of the films was LSGM and a small amount of impurity phases was detected. The thickness of the prepared films was about 2μm, which is measured by Scanning Ion Microscopy (SIM). The good adherence of the thin films to the porous substrate was observed.抄録全体を表示PDF形式でダウンロード (3843K) -
和田 仁, 新 睦, 尹 景田, 吉田 征治, 石原 公司, 棚瀬 繁雄, 境 哲男2003 年 50 巻 12 号 p. 1084-1088
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーWe have prepared Si based composite alloy powders as anode material for lithium-ion batteries using mechanical alloying technique. Ag-Sn-Si powders with a size of several micrometers are composed of Si, Sn and Ag3Sn alloy phases. The electrochemical experiments reveal that the Ag36.4Sn48 Si15.6 electrode demonstrates better electrochemical performance than the others do in both reversible capacity and capacity retention. It can deliver an initial capacity of-800 Ah/kg and maintain a reversible capacity of approximately 180 Ah/kg even after 300 cycles. The structural changes of Ag36.4Sn48 Si15.6 electrode during cycling were examined by X-ray diffraction analyses. The results reveal that the composite alloy consisting of Si, β-Sn and Ag3Sn phases transforms mostly into that of ternary lithiated phase during Li insertion, and recovers to one involving Si, β-Sn, Ag3Sn and residual Ag2LiSn phases after Li extraction. In this type of lithiation/delithiation process, the alloy electrode suffers from a moderate volumetric variation, which is beneficial for the improvement of the cycle life. It has been found that this new Ag-Sn-Si composite material may be a promising candidate as anode material for Lithium Ion Batteries.抄録全体を表示PDF形式でダウンロード (3299K) -
荒地 良典, 田中 穣, 浅井 彪, 小林 弘典, 栄部 比夏里, 蔭山 博之, 江村 修一, 中田 芳幸2003 年 50 巻 12 号 p. 1089-1092
発行日: 2003/12/15
公開日: 2009/05/22
ジャーナル フリーThe cell performance of Li1-xNi0.5Mn0.5O2 Using Li exhibited a specific capacity of c.a. 150 mAh/g in the voltage range of 2.5 to 4.3 V. XRD and XAFS measurements using synchrotron radiation were carried out to observe the average and the local structural changes during a charging process. As the cell charged, Ni K-edge of XANES spectra showed the chemical shift towards higher energy in the voltage range of 2.5-4.1 V and then no remarkable shift up to 4.3 V. It was found that nickel of x=0 in Li1-xNi0.5Mn0.5O2 was located in divalent and manganese in tetravalent at the octahedral site. Lithium was removed by the oxidation of Ni, resulting in the ordering of cations in the layer, that is, appearance of the monoclinic phase at x=0.5.抄録全体を表示PDF形式でダウンロード (276K)
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