巻号一覧
47 巻, 3 号
選択された号の論文の19件中1～19を表示しています
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君塚 隆行, 石橋 新一郎, 羽田 絋一, 山内 五郎, 大志万 浩一, 佐藤 寿彦2000 年 47 巻 3 号 p. 233-238
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーThis study has been done to clarify some characteristics of ultrafine spinel ferrite particles prepared by a chemical coprecipitation method and to investigate their suppressive effect on mycelial growth of turfgrass pathogen, Sclerotinia homoeocarpa. Average particle sizes of these ferrites ranged from 5 to 30nm as determined by X-ray diffraction and TEM observation. Values of saturation magnetization os of these ferrites were 20 to 80emu/g. The optimum growth temperature for the pathogen was 25°C. The suppression rate of MnFe2O4, Fe3O4 and ZnFe2O4 on the mycelial growth was 20 to 50% at 10°C as compared with the control, though the suppression was not clear at 25°C. CoFe2O4 and Ni0.5Zn0.5Fe2O4 showed stronger suppression rate of 40 to 70% at both temperatures. Optical microscopic observation has revealed that additional CoFe2O4 suppresses the 70% of the mycelial growth rate. The origin of the suppression effect of these ultrafine ferrites has been pursued from the viewpoints of electromagnetic field existing on the surface of the ferrite particles and/or extremely small amount of chemical free-ions dissolved from the surface of particles. The suppressive effect becomes higher with the higher σs of many ferrites, except MnFe2O4, Fe3O4 and Ni0.8Zn0.2Fe2O4. Suppressive effects by free-ions of Ni2+, Co2+ increases dramatically at higher concentration than 100μM.抄録全体を表示PDF形式でダウンロード (3665K) -
桐原 聡秀, 宮本 欽生, 梶山 健二2000 年 47 巻 3 号 p. 239-243
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーThree-dimensional photonic crystals with periodic variations in dielectric constant were fabricated by a stereolithographic method of rapid prototyping. The structures were composed of millimeter-order epoxy lattices and designed to exhibit forbidden bands of GHz radio frequencies in millimeter-wave range. To increase dielectric constants of the lattices for wider forbidden bands, silica ceramic particles were dispersed into the epoxy. The attenuation of transmission amplitude through the photonic crystals, which was measured as a function of frequency by using network analyzer, showed the formation of forbidden gaps in millimeter-wave ranges. These photonic crystals are expected to apply for high performance directional antennas and barriers against electromagnetic interference.抄録全体を表示PDF形式でダウンロード (3697K) -
粂 正市, 鈴木 一孝, 金武 直幸2000 年 47 巻 3 号 p. 244-250
発行日: 2000/03/15
公開日: 2009/12/04
ジャーナル フリーDiamond/alumina composites were tried to sinter by both routes of hot pressing (HPing) and hot isostatic pressing (HIPing), in which both sintering conditions are thermodynamically unstable for diamond. When the composites were sintered by the HIPing under 150 MPa at 1423-1473 K for 10.8 ks and by the HPing under 36 MPa at 1673 K for 10.8 ks, the transformation of the diamond into graphite in the composites was not detected by an XRD analysis. Adding of a little magnesia and titania as sintering additives was very effective for the densification and hardening of the composites. Dispersing diamond was effective to restrain the alumina grain growth during the sintering. The Vickers hardness of the composites containing 10 vol.% diamond processed with the sintering additives was slightly increased as compared with that of the alumina with no diamond. It was revealed that the diamond/alumina composites could be successfully sintered by both hot isostatic pressing and hot pressing under thermodynamically unstable conditions for diamond.抄録全体を表示PDF形式でダウンロード (6019K) -
右京 良雄, 須田 明彦, 正木 英之, 小林 哲郎2000 年 47 巻 3 号 p. 251-256
発行日: 2000/03/15
公開日: 2009/12/04
ジャーナル フリーHigh temperature oxidation test of α'/β' Sialon composite containing small a amount of Y-α'-sialon was conducted between 1200 and 1400°C for up to 96 hours in static air. When the oxidation temperature was higher than 1300°C, many voids were formed on the surface and the strength after oxidation decreased drastically due to the formation of pit in the matrix near surface. It is thought that these pits are formed by the local destruction of the oxidized layer during oxidation. A large amount of Y and Al diffused from inside of matrix to the surface, and concentrated in the oxidized layer.抄録全体を表示PDF形式でダウンロード (8032K) -
右京 良雄, 須田 明彦, 正木 英之, 小林 哲郎2000 年 47 巻 3 号 p. 257-263
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーSialon composite composed of Y-α'-sialon and β'-sialon was obtained by hot-pressing the mixtures of Si3N4, Y2O3 and A1N powders. Ten kinds of Si3N4 powder were used as starting materials to investigate the effect of powder characteristics on the sintering behavior of this system. It is found that the oxygen content of Si3N4 powder has large effect on the sintering behavior and the amount of Y-α'-sialon after sintering. On the other hand, the lattice constant of Y-α'-sialon and β'-sialon after sintering were independent on the oxygen content of Si3N4 powder.抄録全体を表示PDF形式でダウンロード (4333K) -
奥田 裕之, 豊田 幸夫, 齊藤 格, 松原 兼2000 年 47 巻 3 号 p. 264-267
発行日: 2000/03/15
公開日: 2010/07/12
ジャーナル フリーWe have newly developed the high-speed response optical shutter composed of Al plane electrodes on a (Pb, La)(Zr, Ti)O3(PLZT) substrate. The surface-reduction-treatment for the PLZT substrate, which included sputtering Al film on the substrate, annealing them in N2 atmosphere, finally removing off the Al film, was found to improve the optical shutter performance under continuous driving. For the shutter using the surface-reduction-treated substrate, optical leakage in a shutter-off-state remained small after continuous driving. The surface resistance of the PLZT substrate decreased 5 orders of magnitude by the surface-reduction-treatment. The decreasing resistance of the surface can reduce concentration of electric field near the edges of electrodes, resulting in improving performance of the PLZT optical shutter.抄録全体を表示PDF形式でダウンロード (1518K) -
上平 一茂, 本多 均一, 藤井 忠行2000 年 47 巻 3 号 p. 268-272
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーEffects of rolling reduction and amount of La2O3 dopant on the development of annealing textures in dispersion strengthened molybdenum sheet were investigated by means of X-ray diffraction technique. The components of rolling and primary recrystallization textures in the dispersion strengthened molybdenum sheet were substantially similar to those obtained for other refractory b.c.c. metals, i.e. three principal components {100} <011>, {111} <hkl> and {112} <110>, regardless of whether rolling reduction of 85 to 95 % or amount of La2O3 dopant of 0.01 to 1.0 mass % was incorporated. At a high temperature anneal, however, different components were developed as a result of secondary recrystallization (abnormal grain growth), i.e. one component of near {100} <011> for the sheet rolled to a reduction of 95 % and doped with 0.01 mass % La2O3, and a strong component of near {112} <110> for the sheets doped with 1.0 mass% La2O3 and rolled to 85% and 95%.
Consequently, the main components of secondary grains developed from dispersion strengthened molybdenum sheets corresponded to weak components in the primary recrystallization textures and were related by a rotation of approximately 20°-30° about <110> axis relative to the strong primary {100} <001> and {111} <110> components.抄録全体を表示PDF形式でダウンロード (367K) -
Yoshihiro Kawaguchi, Yutaka Yanaba, Koji Hayashi2000 年 47 巻 3 号 p. 273-281
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーWe have already clarified that our derived equations of σm=ΨKICSmf1/2 as well as σd-1=σo-1+Ka1/2 are applicable to various hard or brittle sintered materials such as WC-Co hardmetal and Si3N4 ceramics (σm: flexural strength, Ψ: shape factor, KIC: fracture toughness, Smf: total macroscopic fracture surface area of fragments, σd: external stress which operated on the fracture origin, σo: intrinsic or attainable fracture strength, K: material factor, a: half length of fracture origin). In this study, we investigated whether these two equations are applicable to soda lime glass which is non-crystalline and has extremely low KIC. It was found that both equations are also applicable to soda lime glass, when Smf+Sc is used in the application of the former equation, instead of Smf (Sc: the total macroscopic fracture surface area of internally stopped cracks). The fracture started from a visible microstructural defect with sizes of 10-30μm even for polished test pieces with σm values of 180-78 MPa. A correction was made in the derivation process of the former equation: the equation itself, however, was not changed.抄録全体を表示PDF形式でダウンロード (6046K) -
高橋 清造, 中川 威雄2000 年 47 巻 3 号 p. 282-286
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーA long-thin cylider shaped compact was formed from MgO granule admixed with BINDCERAM, toluene and liquid paraffin by a single action tooling of flow compaction. The green density increased according to the liquid paraffin content and the sitered density of relative density 99% to MgO real density 3.58 g/cm3 was gotten by admixing 2 mass% BINDCERAM, 8 mass% toluene and 8 mass% liquid paraffin. This is caused by the reason that liquid paraffin affects a higher volume ratio of MgO powder in green compact. In the case of green compact formed from granule with sufficient flowability by admixing 8 mass% liquid paraffin, the powder flowed from higher densified upper portion to lower in a die cavity during a single action tooling and the difference in local density in green compact could be reduced. Therefore, the diameter of sintered compact was shrunk uniformity from green compact and the dimensional precision of sintered compact was improved if though the shrinkage of diameter was 17%.抄録全体を表示PDF形式でダウンロード (1664K) -
橋井 光弥, 徳満 和人2000 年 47 巻 3 号 p. 287-290
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーThe structure change for Fe50Al5O in mechanical alloying of elemental powders was studied by VSM and 57Fe Mössbauer spectroscopy. Their Mössbauer spectra changed from ferromagnetic sextet to paramagnetic doublet with milling time. Paramagnetic component increased with milling time while ferromagnetic component decreased. The paramagnetic component became to appear in initial stage, 36ks milling. Single doublet spectrum was obtained after 1800ks milling, which was fitted with 2 paramagnetic doublets. The first doublet had 0.224mm/s in isomer shift and 0.207mm/s in quadrupole splitting and the second one had 0.195mm/s and 0.448mm/s respectively.抄録全体を表示PDF形式でダウンロード (307K) -
永井 宏2000 年 47 巻 3 号 p. 292
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (117K) -
尾崎 公洋, 小林 慶三, 西尾 敏幸, 松本 章宏, 杉山 明2000 年 47 巻 3 号 p. 293-297
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーDischarge and sintering phenomena are investigated by measuring current and voltage in pulsed electric current sintering. Fine Al powders under 10μm in particle size and coarse Al powders over 100μm are used. A BN die and a graphite die are used and a graphite punch is used for each die. With BN die and fine Al powders, no current flows until voltage attains 24V. At this voltage a large current over 600A suddenly flows. Some large pores produced by melting and evaporating are observed in the specimen. Discharge occurs when a BN die is used. This discharge can occur in the range of resistivity 10kΩ-1MΩ. The coarse powders can be sintered without discharge. When fine Al powders are sintered using a graphite die, the current and voltage increase simultaneously at the starting stage of sintering. The current depends on the resistivity of powders. The powder compact is sintered from the surface, and then the center region is sintered later. A current almost flows through the graphite die except for fine Al powders. The coarse Al powders can be sintered homogeneously because of current flows through the powders. No discharge occurs with graphite die, and the temperature rises by joule heating.抄録全体を表示PDF形式でダウンロード (3515K) -
Toshinori Isobe, Mamoru Omori, Toshio Hirai2000 年 47 巻 3 号 p. 298-301
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーEutectic composites of Al2O3-Y3Al5O12(YAG) were prepared from solids melted by arc discharge and induction heating. Unidirectional solidification was carried out by the floating zone (FZ) method. The melt of the arc discharge was cooled rapidly and resulted in medium crystals. Coupled crystals (Al2O3 and Y3Al5O12) resulting from induction heating and the FZ method were 20-30, um in width. The eutectic powder, which was prepared by grinding eutectic solids melted by arc discharge and induction heating, was consolidated by the spark plasma system (SPS). The structure of the consolidated was similar to that of a eutectic composite, and was coarsened by the growth of coupled crystals around original particles.抄録全体を表示PDF形式でダウンロード (6867K) -
菊池 圭子, 康 燕生, 川崎 亮2000 年 47 巻 3 号 p. 302-307
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーThis paper describes powder metallurgical fabrication of an FGM compliant pad which is used as electrode as well as conductible coupling between thermoelectric (TE) module and heating or cooling duct. The compliant pad is designed to allow high heat flux with direct conduction path to heat source and heat sink, resulting in the increase of the efficiency of thermoelectric energy conversion. In addition, it offers the structural flexibility to protect the TE module from high thermal stress due to the mismatch of thermal expansion coefficient, electrical insulation between the electrode and the duct and in-plane electrical conductivity by the use of symmetric FGM structure. Nickel and alumina powders are used for raw materials. The optimization of compositional gradient for symmetric FGM has been performed by using thermal stress and thermal conduction analysis. Nickel/alumina symmetric FGMs have been successfully fabricated by spark plasma sintering process under the suited condition for the densification of nickel and alumina powder compacts.抄録全体を表示PDF形式でダウンロード (3359K) -
杉山 重彰, 浅利 孝一, 泰松 斉2000 年 47 巻 3 号 p. 308-314
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーDense TiB2-TiCxN1-x and TiB2-Ti(C0.5N0.5)y composites were synthesized from powder mixtures of B4C, BN and Ti by reactive spark plasma sintering. The reaction 2xB4C+2(1-x)BN+3(x+1)Ti→(3x+1)TiB2+2TiCxN1-x for TiB2-TiCxN1-x and the reaction B4C+BN+(5/2+2/y)Ti→5/2TiB2+2/yTi(C0.5N0.5)y for TiB2-Ti(C0.5N0.5)y, proceeded during their sintering. The relative density of the TiB2-TiCxN1-x composites increased as the nitrogen content decreased, and the composites had relative densities more than 99 % at higher x than 0.5. The Young's modulus, Vickers hardness and fracture toughness of the composites increased with increasing x. For TiB2-Ti(C0.5N0.5)y composites, the relative density became still higher than 99.1 % at smaller y than 1, i.e., increasing nonstoichiometry. However, the Young's modulus, Vickers hardness and fracture toughness decreased with decreasing y value.抄録全体を表示PDF形式でダウンロード (5067K) -
Wei Fang, Se-hyun Ko, Hitoshi Hashimoto, Toshihiko Abe, Yong-ho Park2000 年 47 巻 3 号 p. 315-321
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーPowder compacts for Ti3A1-xNb (x=0, 3, 7, 11, 13 at%) alloys were prepared by pulse discharge sintering at 1173-1573 K and their microstructures, oxidation resistance and mechanical properties were evaluated. The microstructure changed with sintering temperature and Nb content. At lower sintering temperatures, unreacted Ti and Nb were identified by X-ray diffraction and SEM-EDX, and Nb-rich phase primarily existed in the boundaries of Ti3M grains. Increasing sintering temperature obviously improved homogeneity of microstructure. Microhardness, oxidation resistance of compacts increased with sintering temperature and Nb content. For Ti3AI, only pillar-like TiO2 formed after oxidized at 1273 K in air. Adding Nb to Ti3AI, oxide scale was dense and composed of fine particles of TiO2 doped with Nb.抄録全体を表示PDF形式でダウンロード (6472K) -
玉利 信幸, 近藤 功, 田中 隆裕, 斎藤 雅弘, 川原 正和, 鴇田 正雄, 巻野 勇喜雄, 三宅 正司2000 年 47 巻 3 号 p. 322-326
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーOn fabrication of dense silicon carbide sintered bodies added with boron and carbon by spark plasma sintering, the use of silicon carbide raw material with smaller particle size and lower impurities was found to be important.抄録全体を表示PDF形式でダウンロード (2529K) -
杉山 明, 小林 慶三, 松本 章宏, 尾崎 公洋, 西尾 敏幸2000 年 47 巻 3 号 p. 327-331
発行日: 2000/03/15
公開日: 2009/05/22
ジャーナル フリーThe formation process of Mn-Si thermoelectric material made by mechanical alloying followed by pulsed current sintering was investigated. The MA was performed in a planetary ball mill using two elemental powders. The composition of milled powders was MnSi1.85. From the results of thermal analysis by DSC it can be stated that the thermoelectric phase, MnSi1.73, was formed at about 800K. The shrinkage of sintering sample using MA powder during SPS was stagnant at about 800K because of formation of MnSi1.73 phase. Then the shrinkage of sintering sample using MA powder shows a sharp rise at about 900K because the formation of MnSi1.73 was finished. XRD shows the sample sintered at 900K consisted of only MnSi1.73 phase.抄録全体を表示PDF形式でダウンロード (2040K) -
松井 則男, 山田 隆志, 小林 慶三, 杉山 明, 尾崎 公洋2000 年 47 巻 3 号 p. 332-336
発行日: 2000/03/15
公開日: 2010/11/19
ジャーナル フリーFe-xat%Cr(x=28, 38, 48, 58, 68) powders were synthesized by a mechanical alloying (MA) of elementary Fe powder and Cr powder. The MA was performed in a planetary ball mill for 360ks under 1.33kPa argon gas atomosphere. The MA powders were consolidated at 1123K for 0.3ks by a spark plasma sintering (SPS) apparatus. The shape of sample was 15mmφ× 3mmtor 5mmt. The properties of the sintered bodies, namely the coefficient of linear expansion(15mmφ×3mmt) from 303K to 773K and the polarization curve in a 0.1N H2SO4 solution were measured. As the increase of Cr content in the alloy, the coefficient of linear expansion decreased and corrosion resistance was improved. In spite of containing 32at%Fe, corrosion resistance of Fe-68at%Cr alloy was almost the same as that of pure Cr.抄録全体を表示PDF形式でダウンロード (384K)
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