巻号一覧
43 巻, 6 号
選択された号の論文の20件中1～20を表示しています
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和久 芳春, 鈴木 道之1996 年 43 巻 6 号 p. 705-711
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーNew simultaneous toughening and strengthening method for Al2O3 composites has been reviewed. The flake-forming behavior of refractory metal powders such as Mo, Ta and Nb by MA process, and three-point flexural strength and fracture toughness of Al2O3 composites reinforced with flaky Mo particles have been investigated. The flake-forming behavior of Mo powders mixed with Al2O3 powders becomes prominent with increasing Mo particle size, while remaining almost independent of Mo volume percent. The fracture toughness increases with increasing Mo particle size which corresponds to an increase of the flake-forming tendency of these particles. Furthermore, the fracture toughness and flexural strength can be simultaneously improved by increasing the volume percent of flaky Mo particles. The microstructural observations indicate that the improvement in fracture toughness may be due to plastic deformation of Mo particles at a crack tip and crack-deflection or crack-bridging which are accelerated more by the flaky rather than the small. spherical shape.抄録全体を表示PDF形式でダウンロード (4951K) -
藤井 勲, 森井 賢二1996 年 43 巻 6 号 p. 712-716
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーIn this work, the effects of deposition and annealing conditions on the dielectric properties and dc conductivity were investigated on the thin amorphous SrTiO3 films prepared by a sputtering method using neutralized argon-ion beams. It was demonstrated that the dielectric constant and dc conductivity increased markedly by vacuum annealing and by increasing the target-substrate distance during deposition. The amorphous SrTiO3 films have the optical band gap of about 2.5eV, accompanying with rather wide band tails. This suggests the existence of structural defects which may be caused by oxygen deficiency in the amorphous structure. The amounts of the oxygen deficiency were considered to be dependent on the annealing atmosphere as well as the target-substrate spacing. It is supposed that the ionization of oxygen vacancies, Vo→Vo¨+2e', plays an important role for the dielectric properties and dc conductivity of the amorphous SrTiO3 thin flms. The relative dielectric constants obtained ranged from 20 to 550.抄録全体を表示PDF形式でダウンロード (292K) -
白 種甲, 五味 健二郎, 磯部 徹彦, 仙名 保1996 年 43 巻 6 号 p. 717-721
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe formation process of perovskite solid-solution 0.9Pb(Mg1/3Nb2/3)-0.1PbTiO3 (0.9PMN-0.1PT) from a stoichiometric mixture of PbO, Nb2O5, TiO2 and Mg(OH)2 by a soft-mechanochemical technique was studied. Single phase of perovskite 0.9PMN-0.1PT powder was obtained after heating at 850°C for 4 h of the mechanically activated precursor with a stoichiometric composition maintained. After milling a starting mixture for 60 min, Nb5+ was locally reduced to Nb2+ and the amount of -OH in Mg(OH)2 decreased, as confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR), respectively. Formation of precursors seems to be accomplished by preferential solid-state acid/base reactions between Nb2O5 and Mg(OH)2 under mechanical stress. All these observations consistently explain the enhanced rate of formation of perovskite solid-solution 0.9PMN-0.1 PT from the mechanically activated mixture on subsequent heating.抄録全体を表示PDF形式でダウンロード (253K) -
穂刈 勇司, 赤塚 久修, 福永 俊晴, 水谷 宇一郎1996 年 43 巻 6 号 p. 722-725
発行日: 1996/06/15
公開日: 2009/12/04
ジャーナル フリーA mixture of pure Se and S powders has been subjected to mechanical alloying(MA) at room temperature. Trigonal Se and rhombic S are built up of chain and ring molecules, respectively. Therefore, this process means the mixing of chain and ring molecules. X-ray diffraction patterns during the milling process indicate that the amorphization proceeds with increasing milling time. The amorphous Se-S powders sample shows endothermic and exothermic peaks in the DSC spectrum, which are a glass transition and crystallization respectively. The glass transition temperature decreases with increasing the S concentration. However, the crystallization temperature of the Se-7at%S amorphous sample becomes larger than that of the amorphous Se. This is related to the fact that the Se-7at%S amorphous sample is constructed by the tangled chain and ring molecules.抄録全体を表示PDF形式でダウンロード (205K) -
永野 啓, 金谷 利治, 福永 俊晴, 水谷 宇一郎1996 年 43 巻 6 号 p. 726-730
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe mechanical milling of PVA(polyviny l alcohol) under an Ar atmosphere was carried out at room temperature. So far, no complete amorphous PVA has been reported to be synthesized by any other methods. Bragg peaks of the crystal phase in the PVA, however, became broadened with increasing milling time. After 200 hours of milling a halo pattern dominated. The result, therefore, led us to conclude that the amorphization of the PVA was caused by the mechanical destruction of the crystal structure. The amorphization of the PVA was also confirmed through the observation of low energy excitation by inelastic neutron scattering. A drastic change within 5Å in the radial distribution function RDF(r)was not observed. On the contrary, the correlation distance of the atomic distribution became shorter with increasing milling time. The results suggest that the milling transforms straight long chain molecules into tangled ones in PVA.抄録全体を表示PDF形式でダウンロード (241K) -
増山 圭一, 梅本 実, Krishnamurthy Raviprasad, 稲垣 隆, 大井 宏志1996 年 43 巻 6 号 p. 731-737
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe characterization and consolidation of mechanically alloyed M99.7(C60, C70)0.3 mol% and M84.3C15.7 at% (M=Al, Cu, Fe) powders were carried out. The mechanical stability of carbon fullerene(C60, C70) was studied in a preliminary experiment prior to MA (metal fullerene). The result has shown that the fcc structure of fullerene (C60, C70) remAlns after long time milling. In addition, a new molecule probably a dimer of C60 is formed during milling. The phase changes of the processed powders with milling time were studied using x-ray diffraction and high performance liquid chromatography. The MA powders were subsequently sintered by plasma sintering machine. The phases present, microstructure, hardness of the sintered compacts were studied using TEM, X-ray diffraction and vickers hardness tester. In the Al- and Fe-fullerene system, Al4C3 and Fe3C formed during sintering of Al-(C60, C70) and Fe-(C60, C70) mechanically alloyed powders respectively. In TEM micrographs of Cu-fullerene MA powders very fine Cu particles were observed around MA powder. These fine particles were considerd to be produced by the evaporation of Cu from MA powder by electron beam irradiation. This indicates that the powder is heated by electron beam and separation of Cu and carbon takes place.抄録全体を表示PDF形式でダウンロード (5517K) -
永野 啓, 若山 博昭, 福嶋 喜章, 福永 俊晴, 水谷 宇一郎1996 年 43 巻 6 号 p. 738-741
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe crystal structure of graphite is characterized by layers, the large separation of which (3.35 Å) compared with the C-C bond length of 1.42Å in the layers indicates relatively feeble binding between the atoms of different layers. X-ray diffraction patterns indicate that the layer structure of the graphite was transformed into amorphous-like one by mechanical milling. TEM image also shows that the layer structure of graphite has disappeared after milling. This suggests that the milling conducts a large amount of strains in the layers. The atomic distribution within 3 Å in the radial distribution function RDF(r) observed by neutron diffraction indicates no drastic change in position. On the contrary, the coordination number of the 1st nearest neighbor gradually decreased with increasing milling time. The results allow us to conclude that the size of the graphite becomes smaller by milling and approaches to be about 30 Å in diameter in plane after 36 hours of milling.抄録全体を表示PDF形式でダウンロード (1280K) -
田中 武雄, 吉川 浩美, 兼吉 高宏, 元山 宗之, 石原 慶一, 新宮 秀夫1996 年 43 巻 6 号 p. 742-747
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーBall-milling of graphite powder was performed by the use of a stainless steel ball-mill and an agate ball-mill. The crystal structure of the ground graphite was studied by transmission electron microscopy and X-ray diffractometry. A spectrometric approach to the change of structure during the milling process was also carried out by the carbon Kα X-ray-emission band spectroscopy (XES). The carbon Kα XES spectra were compared with those of carbon materials such as ball-milled diamond powder, i-diamond film and amorphous carbon powder. In the case of the stainless steel ball-milling, microcrystalline and/or onion-like structure were formed. The XES spectrum suggested that sp3 hybrid orbital was formed after 2000 h of milling. While, in the case of an agate ball-milling, it was suggested that the 2p orbital became narrow as a result of further finely-ground pulverization of graphite crystallite after 1750 h of milling.抄録全体を表示PDF形式でダウンロード (3115K) -
中塚 勝人1996 年 43 巻 6 号 p. 750
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (74K) -
神山 新一1996 年 43 巻 6 号 p. 751-756
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーA recent development in magnetic fluids research is reviewed. The research activities in this field are increasing accompanied with the success of the synthesis of magnetic fluids with excellent magnetic properties. Apparent viscosity and rheological properties are discussed in connection with the particle aggregates in the applied magnetic field. As the thermo-fluid dynamics of magnetic fluids, recent investigations on the pipe flow problems and heat transfer control are taken up. Finally, as the representative examples of recent studies on the applications of magnetic fluids, various sensors, actuators, grinding device and heat pipe are explained.抄録全体を表示PDF形式でダウンロード (349K) -
藤田 豊久, 伊藤 亮治, 葛野 栄一, 河野 研治1996 年 43 巻 6 号 p. 757-760
発行日: 1996/06/15
公開日: 2009/12/04
ジャーナル フリーThe coprecipitated magnetite particles were coated by anionic surfactant, that is, polyoxyethylene alkyl ether acetates whose hydrophile-lipophile balance was about 6. The surfactant coated magnetite was washed by ethanol to remove excess amount of surfactant on magnetite surface. The washed magnetite particles were well dispersed in methyl phenyl polysiloxane. The saturation magnetization of concentrated silicone oil based magnetic fluid was approximately 0.05T. When the magnetic fluid was used in a cylindrical damper, the magnification factor at resonance point decreased and the frequency at resonance point depended on amplitude of damper.抄録全体を表示PDF形式でダウンロード (196K) -
藤田 豊久, 伊藤 亮治, 和田 泰久, 赤上 陽一1996 年 43 巻 6 号 p. 761-765
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe coprecipitated magnetite particles were coated by polyoxyethylene alkyl ether acetates. After the surfactant coated magnetite was washed by ethanol, they were well dispersed in nematic liquid crystal, that is, cyanobiphenyl type and phenylcyclohexane type liquid crystals. The saturation magnetization of prepared liquid crystal based magnetic fluid was 0.1 to 0.2 T. However, as decreasing the temperature of magnetic fluid, the phase separation appeared. Also this magnetic fluid showed the electrorheological effect, therefore, this fluid was considered as ER magnetic fluid. When the magnetic fluid was used in a cylindrical damper, the magnification factor at resonance point slightly decreased.抄録全体を表示PDF形式でダウンロード (215K) -
島田 邦雄, 藤田 豊久, 岩渕 牧男, 奥井 健一1996 年 43 巻 6 号 p. 766-770
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーExperimental study was conduted on rheological characteristics of an electrorheological fluid (ER fluid) with elastic particles which is made of smectite as one of new typed colloidal ER fluid in the rotaing flow in an applying electic field. The rotating flows of the viscometer which was operated within electric field were made by two types of concentric rotating cylinder and a rotating disk. The experimental data were estimated with the theory with taking into account the elatisity of the particles. The difference of the effect of electric field strength and shear rate in the two types of rotating flow was clarified.抄録全体を表示PDF形式でダウンロード (281K) -
島田 邦雄, 藤田 豊久, 岩渕 牧男, 奥井 健一1996 年 43 巻 6 号 p. 771-776
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーTheoretical investigation was made on the hydrodynamic characteristics taking into account the effect of the particles of electrorheological fluid (ER fluid) which is a type of colloidal dispersion. First of all, the numerical calculation supposing the uniform dispersion of each sphere particles were made and the results were compared with the experimental data at the case of rotating flow in concentric cylinder as one of the cases of fluid flow. Secondly, the quantitative or qualitative difference between them was investigated under the assumption that the cause of the difference is aggregation of the particles, and the difference was estimated with using the equation of the increment of viscosity by applying an electric field taking into account the aggregation.抄録全体を表示PDF形式でダウンロード (321K) -
岡 英夫1996 年 43 巻 6 号 p. 777-781
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThis paper shows the experimental results for the measurements of complex magnetic permea-bility of ring-shaped magnetic woods as a function of frequency between 1 MHz and 1.8 GHz. Comparison of complex permeabilities between magnetic fluid and magnetic powder are also shown. The results show that the complex permeability of magnetic wooden materials using magnetic powder is higher than that of the wood impregnated with a magnetic fluid at high frequency. In both cases, the imaginary components of complex permeability increase with frequency.抄録全体を表示PDF形式でダウンロード (267K) -
岡 英夫1996 年 43 巻 6 号 p. 782-786
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe purpose of this paper is to propose a method for measuring the permeability of a magnetic fluid with a ferrite core, with a gap, where the core is excited and placed within the magnetic fluid. Several different materials and sizes are examined. Comparative experiments with the ring core method show that the proposed method is more effective for measuring ac permeability.抄録全体を表示PDF形式でダウンロード (217K) -
研削加工損傷への応用西 誠, 杉田 忠彰, 舟田 義則1996 年 43 巻 6 号 p. 789-794
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe strength reliability of the PSZ ceramics with grinding damages under cyclic loading is evaluated by the crack growth parameters of grinding damage model, which is estimated from the result of fatigue testing. The result of cyclic four point bending test of ceramics specimens with grinding surface shows that the fatigue characteristics depends on the initial crack length and density of cracks caused by grinding. In order to estimate the model of cracks on grinding surface, the initial crack length and the length of crack growth during cyclic bending is measured from the fatigue fractured surface. Also the density of cracks is assumed from an approximated life curve at the fatigue characteristics. And then the crack growth parameters m, C and fatigue fracture toughness value Kfc are calculated using the estimated model of cracks. Further, statistical characteristics of the crack growth parameters for the ceramics with multiple cracks are expressed by Weibull distribution function in the ceramics with single cracks. The evaluated strength reliability agrees with a fatigue characteristics of ceramics with grinding surface under cyclic four point bending. Therefore, it is found that the proposed method in this study is sufficiently effective for the strength reliability evaluation of ceramics with grinding damages.抄録全体を表示PDF形式でダウンロード (2946K) -
李 吉根, 大平 俊之, 星野 孝二, 河野 通, 山岸 宣行1996 年 43 巻 6 号 p. 795-800
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーTo prepare a SnO2 particle dispersed nano structured silver alloy by mechanical alloying process, the mixtures of SnO2 and silver powder were tumbler-ball milled in the air atmosphere, using ethanol as a milling surfactant. The milling process and phase formation were monitored by X-ray diffraction analysis(XRD), optical microscopy, SEM, EPMA and TEM of the milled powder. The milled powders were consolidated by conventional sintering process and extrusion process. The microstructure of the consolidated compacts was observed by optical microscopy and TEM. Fine SnO2/silver composite powder particle with a microstructure of nano size SnO2 particles were homogeneously dispersed throughout the silver matrix, was formed after 100h milling, in spite of milled in the air atmosphere. It was difficult to obtain densed and homogeneous nano structured SnO2/silver consolidated compact by conventional sintering pro-cess, because phase separation between dispersion phase, SnO2, and matrix phase, silver, during sintering of the composite powder particles milled over 50h milling time. It was possible to obtain densed and homogeneous ultra-fine microstructured SnO2/silver alloy by combination of mechanical alloying and extrusion process which occurs severe mass transfer during consolidation.抄録全体を表示PDF形式でダウンロード (6517K) -
李 吉根, 大平 俊之, 野星 孝二, 河野 通, 山岸 宣行1996 年 43 巻 6 号 p. 801-806
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーPowder pre mixture of SnO2 and silver was tumbler-ball milled to investigate the influence of milling effect on the phase separation between oxide phase and matrix phase during heat treatment of mechanical alloyed oxide dispersided metal matrix composite particles. The milled powder for period milling time was heat treated in the air atmosphere, and the microstructure and phase formation during heat treatment were monitored by X-ray diffraction analysis(XRD), optical microscopy, SEM, EPMA and DTA. The cross section area ratio of the pure silver to total particle of the heat treated composite particles was measured with heat treatment temperature as function of milling time and volume fraction of SnO2, using image analysis system. The separation between dispersion phase, SnO2, and matrix phase, silver, was occurred when heat treated over the critical temperature of the composite particle milled over the period milling time. It considered that the separation phenomenon between dispersion phase and matrix phase during heat treatment was caused by mass transfer started by the release of internal energy which stored in the composite particle during mechanical alloying.抄録全体を表示PDF形式でダウンロード (3571K) -
勝山 茂, 田中 芳幸, 真島 一彦, 永井 宏1996 年 43 巻 6 号 p. 807-812
発行日: 1996/06/15
公開日: 2009/05/22
ジャーナル フリーThe effectiveness of substitution for La by Ba or Ca on the physical properties of rare earth chalcogenide La3S4 was examined. Cubic γ -phase (Th3P4-type) was obtained in the range of 0≤x≤1 in La3-xAxS4 (A=Ba, Ca). The lattice parameter in La3-xBaxS4 system increased, while that in La3-xCaxS4 system decreased with an increase of x, which is ascribed to the difference of the radius among the ions. The thermoelectric power (α) and the electrical resistivity (ρ) of La3-xAxS4, which are functions of the electron concentration, increased with an increase of the temperature and the alkaline earth metal content x. A maximum value of the power factor (p=α2/ρ) at high temperature above 750K was obtained at x=0, i.e., La3S4. On the other hand, the thermal conductivity (κ) decreased with an increases of x. In result, a maximum value of the figure of merit (Z=α2/(ρκ)) was obtained at large value of x (x≈0.6 in La3-x, BaxS4 and x≈0.8 in La3-xCaxS4).抄録全体を表示PDF形式でダウンロード (342K)
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