巻号一覧
41 巻, 2 号
選択された号の論文の23件中1～23を表示しています
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中塚 勝人1994 年 41 巻 2 号 p. 104
発行日: 1994/02/15
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) -
島田 邦雄, 神山 新一, 佐藤 彰1994 年 41 巻 2 号 p. 105-108
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe measurement of volumetric change of magnetic fluid influenced by pressure is experimentally conducted. Positive or negative pressure is applied to the magnetic fluid in a nonuniform magnetic field. The experimental results are compared with the data in the case of water. It is clarified that the volume change of magnetic fluid is strongly influenced by the applied pressure and also the applied magnetic field.抄録全体を表示PDF形式でダウンロード (290K) -
Balachandran Jeyadevan, Kazuyuki Tohji, Katsuto Nakatsuka1994 年 41 巻 2 号 p. 109-112
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe unusually high magnetization of co-precipitated zinc ferrite has been interpreted as a consequence of magnetic clusters that are supposed to be formed by AB interaction of Fe ions in octahedral and tetrahedral sites. In this paper, the local structure around Fe and Zn atoms is discussed by measuring with the Extended X-ray Absorption Fine Structure (EXAFS). The structure around Zn atom was found to differ between zinc ferrite by ceramic and co-precipitation technique. The position of the peak referring to the second nearest neighbor of Zn atom was shorter in the case of co-precipitated zinc ferrite. This is believed due to the possible occupation of the Zn atoms in the octahedral sites. Further, the intensity of the peak is weak compared to the one produced by ceramic method. This has been thought to be due to the deformation induced by the occupation of zinc ions in the octahedral sites causing a decrease in the area of structural periodicity in the short range order.抄録全体を表示PDF形式でダウンロード (266K) -
Balachandran Jeyadevan, Kazuyuki Tohji, Katsuto Nakatsuka1994 年 41 巻 2 号 p. 113-116
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe particles in magnetic fluid relaxes in the field direction through either Neel or Brownian relaxation. The relaxation mechanism is very much influenced by the anisotropy constant of the particle. In this paper, the relaxation mechanism under various states and conditions for magnetite and cobalt ferrite magnetic fluid in the temperature range of 83-293K is discussed by measuring the initial susceptibility of the system. Our results suggest that the magnetite magnetic fluid contains a mixture of non-superparamagnetic and superparamagnetic particles, whereas, the cobalt ferrite magnetic fluid contains exclusively of nonsuperparamagnetic particles. The results of local structure analysis on coprecipitated magnetite was comparable to that of Kamaishi magnetite except the distance between Fe and 0 atoms which was shorter. This suggests the possible vacancies in the octahedral sites in co-precipitated magnetite. In the case of coprecipitated cobalt ferrite, the Co and Fe atoms are well dispersed in the structure. The distance of the second nearest neighbor peak at Fe K-edge shows a decrease and at the same time at Co K-edge shows an increase meaning a slight difference in the cation distribution compared to cobalt ferrite produced by ceramic method.抄録全体を表示PDF形式でダウンロード (266K) -
藤田 豊久, 吉野 健司, 山口 邦彦1994 年 41 巻 2 号 p. 117-120
発行日: 1994/02/15
公開日: 2009/12/04
ジャーナル フリーWe report the preparation of electrorheological magnetic fluid and its rheological property under electromagnetic field. The ultrafine magnetite (≈10nm) was partially coated with gold by nonelectrolytic plating using gold (III) trichloride acid and sodium citrate. The partially plated particles were coated with surfactant and then dispersed stably in insulated oil such as kerosene. This fluid showed electrorheological property by applying electric field. When both magnetic and electric fields were applied to the fluid, the increase in shear stress mainly depended on electric field of 2kV/mm, not on magnetic field. This fluid has the property of magnetic fluid, for example, being stably retained in the electrode gap under a magnetic field. By applying both electric and magentic fields on this fluid, the new applications in damper, actuators and so on will be expected.抄録全体を表示PDF形式でダウンロード (1655K) -
岡 英夫1994 年 41 巻 2 号 p. 121-124
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe author previously reported the magnetic characteristics of the magnetic wood which absorbs magnetic fluid. Four manufacturing processes were proposed namely dipping, vacuum pouring, coating and pressing. The sample made by pressing shows the largest apparent permeability, The experiments show that the diffuse-porous wood sample shows larger apparent permeability than the ring-porous wood sample.抄録全体を表示PDF形式でダウンロード (226K) -
岡 英夫1994 年 41 巻 2 号 p. 125-128
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe author previouly reported the magnetic agar which is manufactured by mixing agar and water based magnetic fluid. Magnetic agar has several interesting characteristics, such as water retentivity, viscosity change by temperature and softness. So as to widen the application of magnetic agar the authors measured the permeability to make the magnetic agar which has good dispersibility of ferrite particles. Experimental results of permeability by internal exciting method is also reported.抄録全体を表示PDF形式でダウンロード (234K) -
浅見 淳一1994 年 41 巻 2 号 p. 131-135
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe possibilities of the production of aluminum sintered products by two-step pressing method have been studied. Different from the conventional repressing-resintering approach, two types of dies were employed in the uniaxial compression of powder or green compacts at room temperature. All green compacts were pressed by diewall lubrication in a floating-die tool arrangement. It was noticeable that this method reduced the loads required for ejection of specimens from the die. Consequently, highly stable oxide on the surface of aluminum powder particles could be broken because the compacting pressure was increased, and the bond between particles would be facilitated during sintering.抄録全体を表示PDF形式でダウンロード (5707K) -
黄 鶴年, 李 勇, 中江 秀雄1994 年 41 巻 2 号 p. 136-140
発行日: 1994/02/15
公開日: 2010/07/12
ジャーナル フリーA model consists of a rectangular parallelopiped porous skeleton, which has a straight-cylindrical pores crossing at right angles on three dimensions, is set up, and the liquid was assumed to penetrate into the pores with laminar flow by the capillary and the gravitation forces. The general equation of infiltration introduced in a previous paper was made under the above conditions. In this paper, the general equation of penetration, where the elevating liquid speed from the bottom to the upper of the skeleton having a larger height, was newly produced by reconstruction of the above general equation. This new equation was confirmed by experiments on penetration of aqueous solutions into sintered glass powder porous compacts. The new general equation of penetration is shown as follows;
t=72ηL⋅h∞/R2⋅ρ⋅g⋅∞Σn=2 1/n (h/h∞)n
where, h:penetrating height of liquid(m), R: radius of pore(m), h∞: equilibrium penetrating height of liquid(m), which equals to 2 γLV⋅cos θ∞/R⋅ρ⋅g, γLV: surface tension of liquid (N/m), θ∞: equilibrium contact angle between skeleton and liquid(deg), η L: viscosity of liquid(Pa⋅S), t : penetrating time(s), ρ : density of liquid(kg/m3), and g: constant of gravitation(m/s2).抄録全体を表示PDF形式でダウンロード (306K) -
武川 淳二郎, 瀬戸 秀樹1994 年 41 巻 2 号 p. 141-145
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーEffects of sintering atomospheres on the sinterability of injection molded compacts were investigated. The results obtained were as follows.
1) The sintered density of the injection molded compacts increased with increasing reducing ability in the sintering atmospheres, however this increase was about one third of that of the conventional P/M compacts.
2) In the case of Fe-8Ni injection molded compact, preheating at 450°C for 1 hr. in H-atmosphere enabled to densify it to the relative density of 95% in the subsequent sintering even using the inert gas atomosphere such as pure N2. Whereas the compact without the preheating was not densified unless the ratio of H2 to the H2/N2 gas mixtures exceeded 40 vol %.
3) On the other hand, the sintered density for the case of SUS316L compact was almost same, e.g. the relative density of about 93-94%, with or without the preheating treatment.抄録全体を表示PDF形式でダウンロード (4356K) -
渋江 和久, 古山 努, 金 睦淳, 熊谷 正樹1994 年 41 巻 2 号 p. 146-151
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーFully consolidated mixtures of Ti and Al-7mass%Mn were prepared via powder extrusion. The extruded mixtures were synthesized into TiAI intermetallics by the reactive sintering method using HIP. Effect of extrusion ratio of the mixtures on microstructures and room temperature tensile properties was investigated. Tensile yield strength, ulitimate tensile strength and elongation were increased with increasing extrusion ratio up to extrusion ratio 295, owing to a refined microstructure and an enhanced diffusion at higher extrusion ratio.抄録全体を表示PDF形式でダウンロード (6070K) -
木下 聡, 植木 光生, 鈴木 寿1994 年 41 巻 2 号 p. 152-155
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーIt was reported by the present authors that TiC based cermet sintered after nitrification during raising temperature was superior in creep characteristics, in the similar way to commercially available cermet containing TiN. Then, the present work was undertaken to make clear the cutting performance and the grindability by diamond wheel of the nitrified cermet as above. It was found that the nitrified cermet was also superior in those properties to commercial cermet. The reason was in detail discussed.抄録全体を表示PDF形式でダウンロード (2386K) -
西山 勝廣, 小川 利治, 高木 研一, 大森 守, 梅川 荘吉1994 年 41 巻 2 号 p. 156-161
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーProduction conditions and mechanical properties of magnesium based composites reinforced with aluminum diboride (AlB2), magnesium diboride (MgB2) and amorphous boron of several contents up to 50 vol% were investigated. These composites were produced by hot-pressing at a temperature of 853K and under a pressure of 60MPa in argon. The added boride perticles dispersed fairly well in magnesium matrix. The addition of these borides improved the mechanical properties of the magnesium composites. Especially the bending strength of the Mg-AlB2 increased to a maximum value of 406MPa at 15vol%AIB2. The increase in strength was presumably attributed to a particle dispersion strengthening mechanism in the composites. Other mechanical properties of the composites, such as high temperature hardness, wear resistance and corrosion resistance, were also improved by the addition of the borides.抄録全体を表示PDF形式でダウンロード (3104K) -
西山 勝廣, 永田 尊礼, 高木 研一, 大森 守, 梅川 荘吉1994 年 41 巻 2 号 p. 162-165
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーProduction conditions and mechanical properties of aluminium based composites reinforced with aluminium dodecaboride (AIB12) and magnesium diboride (MgB2) with 0% to 50vol% and 30vol%, respectively, were investigated. These composites were produced by hot-pressing at temperatures of 863K and 923K and under a pressure of 60MPa in vacuum. The added boride particle dispersed fairly well in the alumunium matrix. The addition of AIB12 and MgB2 improved both of the bending strength and hardness of the composites. The bending strength of the Al-AIB12 composites reached a maxmum value of 460MPa at 8.6vol%AI12. The increase in strength was presumably attributed to a particle dispersion strengthening mechanism in the composites. Other mechanical properties of the composites, such as high temperature hardness and wear resistance, were also improved, by the addition of the borides.抄録全体を表示PDF形式でダウンロード (1842K) -
兼吉 高宏, 高橋 輝男, 林 行信, 元山 宗之1994 年 41 巻 2 号 p. 166-169
発行日: 1994/02/15
公開日: 2009/12/04
ジャーナル フリーElemental Al, Nb and B powders with the composition of Al3Nb-xvol%NbB2 (x=10-30) were mechanically alloyed (MA) in an Ar gas atmosphere. The results of X-ray diffraction indicated that an Al3Nb phase and a NbB2 phase, which was considered to be NbB2-x (with lesser stoichiometrical B content), were obtained in 72.0ks MA powders. The sintered compacts with high density were obtained by vacuum heating of the compacts of 72.0ks MA powders. Fine NbB2-x dispersed uniformly in the sintered compacts and its content increased according to the x value in A13Nb-xvol%NbB2. A part of NbB2-x obtained in the sinterd compacts was like a rod in shape. Many rod-like NbB2-x were formed in HIPed compacts which were processed at lower temperature than the sinterd compacts. TEM observation of the HIPed compacts revealed that rod-like NbB2-x, which was as small as nano-meter, precipitated on nano-sized Al3Nb matrix. The hardness of the HIPed compacts was about Hv1000 which was higher than that of Al3Nb.抄録全体を表示PDF形式でダウンロード (3551K) -
落合 鍾一, 土肥 義治, 小島 陽, 村上 雄, 宗宮 重行1994 年 41 巻 2 号 p. 170-175
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe production of TiAl (42 at%Al) based composite with TiC reinforcement (5 vol%) was attempted by a mechanical alloying (MA) method utilizing pure Ti, TiAl prealloyed and graphite powders. The development of MA, microstructure, mechanical properties and oxidation resistance of sintered alloys were investigated. Processed powders after MA for 804 h are characteristically fine and agglomerated with diam. of less than 1 μm. The formation of TiC phase during MA was confirmed. Sintered alloy produced by hot-pressing was found to be consisting of TiAl matrix phase, acicular or platelet TiC particles with 5-10 μm in diam. and a small amount of Al2O3. Higher hardness and flow stress than those of TiAl matrix were observed, suggesting a dispersion strengthening effect. Fracture tended to occur after plastic deformation above 800°C . The existence of the fracture strain, for example no less than 10% at 900°C, is demonstrating the ductility at high temperatures. Slight mass gain measured by oxidation test, compared with the case of arc-melt method, and no spalling of oxide scales were indicating good oxidation resistance of this composite intermetallic alloy.抄録全体を表示PDF形式でダウンロード (6230K) -
高橋 清造, 金井 金井, 中川 威雄1994 年 41 巻 2 号 p. 176-179
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーStepped cup compact were formed by a uniaxial hydraulic press from alumina granule with 3wt% PVA (Polyvinyl Alchohol) after admixing liquid paraffin, and density distribution in green compact was measured. The difference in local density of green compact could be reduced by press flow compaction, in spite of that the decreasing was impossible by dry compaction. It was confirmed that when green compact was formed from the granule with the sufficient flowability by admixed liquid paraffin, the densified powder flowed from the bottom to the cup wall during compaction.
The relative density of sintered compact was 92%, and diameter shrank by 15% in average. In dry compaction, the difference in diameter of the sintered compact is large, but in pressurized flow compaction with lOwt% liquid paraffin the shrinkage was almost uniform along the cup wall.抄録全体を表示PDF形式でダウンロード (1262K) -
田島 俊造, 橋本 重昭, 黒木 英憲1994 年 41 巻 2 号 p. 180-183
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーA slip has been prepared from an alumina powder with the average particle size of 0.22 μm and the purity of 99.99%. Compacts have been formed from the slip in the high speed centrifugal compaction process by a 8-12kG centrifugal force, and sintered in air at 1200-1250°C for 2hr.
The SEM observations on polished and thermally etched sections of the sintered compacts showed fine grain structures with no void. The sintering at 1220°C has given a 3-point bending strength of 1160MPa (Weibull modulus : 20.5), an average particle size of 0.64μm, a relative density of 99.3%, and a Vickers hardness of 2100.
An alumina having high levels of the purity and same characteristics as Hipped materials was obtained in the centrifugal process by only sintering a non-doped green compact in air. One of the reason for obtaining such an excellent property of sintered alumina may be due to complete removal of bubbles during compaction by the high centrifugal force.抄録全体を表示PDF形式でダウンロード (2006K) -
福田 雅秀, 土屋 一彦, 土屋 信次郎, 宮谷 和雄1994 年 41 巻 2 号 p. 184-187
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーSintered body of ZrO2-3.3mass%MgO was prepared, and the bulk density, pore size, transverse-rupture strength (TRS) and the fracture origin were studied in relation with the average particle size ranged from 1.1 to 0.6μm of the powder specimen, which was prepared by an attrition mill with 2-propanol solvent and zirconia ball. The test sample was obtained by sintering at 1680°C×2hr and aging at 1080°C×20hr. TRS was measured by the 3 point-bending and the fracture origin was extensively studied for the samples sintered with three different size particles: 1.1, 0.8 and 0.6μm.
As the particle size was lowered, the bulk density increased from 5.60 to 5.82g/cm3 and both the pore size and its number decreased. TRS of 661, 700 and 623MPa was obtained for 1.1, 0.8 and 0.6μm powders, respectively. Through the observation of transverse-ruptured surface by SEM, the pore was concluded to be responsible as the fracture origin, and the corresponding pore size was measured on each fracture. It was concluded that the 0.8μm sample, in comparison with the 1.1μm sample, increased in TRS by improved solidification and pore size, while the 0.6μm sample lowered in TRS by an over grown grain size in spite of its highly solidified body.抄録全体を表示PDF形式でダウンロード (3182K) -
β-サイアロン(Z=3)の生成過程山岸 千丈, 塚本 惠三, 塩貝 達也, 林 睦夫, 井関 孝善1994 年 41 巻 2 号 p. 188-192
発行日: 1994/02/15
公開日: 2009/12/04
ジャーナル フリーThe reaction processes of β-SiAlON(Z=3) powder using carbothermal reduction and nitridation, were investigated on basis of thermo-gravimetry, CO concentration and XRD analysis. The processes were influenced by the reactivity of Al compounds in raw materials. β-SiAlON was synthesized via mullite using high reactive Al compound (AMD or Al(OH)3), on the other hand, synthesized via α-A12O3 using low reactive Al compound (Al2O3).抄録全体を表示PDF形式でダウンロード (1347K) -
伊賀 篤志, 伊藤 昌宏, 沖中 秀行1994 年 41 巻 2 号 p. 193-195
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーThe exaggerated grain growth of ZnO in the low voltage ZnO varistor was investigated. At a temperature exceeds 1000°C in the sintering process, many thin films were formed in the sintered body which contained TiO2 and Bi2O3. The ZnO grain seemed to grow epitaxially with the thin film. XMA and powder X-ray diffraction analysis suggest that the thin films are Bi4Ti3O12. The growth of the thin films depended on the amount of Al2O3additive. Then the exaggerated grain growth of ZnO was under the control of small amount of Al2O3additive.抄録全体を表示PDF形式でダウンロード (3784K) -
堀野 賢治, 小関 健二, 山松 純子, 人見 篤志, 野村 武史1994 年 41 巻 2 号 p. 196-200
発行日: 1994/02/15
公開日: 2009/12/04
ジャーナル フリーKinetics of solid state reaction and grain growth behavior of BaTiO3-CaTiO3-SrTiO3 system ceramics has been studied. It is shown that the formations of both BaTiO3 and SrTiO3 are due to the phase boundary controlled reaction. On the other hand, that of CaTiO3 is diffusion controlled. Grain growth of this system could be expressed by the equation Gn=kt, where n=8.0 and Q=690kJ/mol (activation energy) were obtained under Po2=10-10Pa. It is possible to control the microstructure of this system by oxygen partial pressure(Po2) during firing. When Po2≤10-8Pa, the microstructure of this system becomes fine and uniform.抄録全体を表示PDF形式でダウンロード (2208K) -
三吉 康晴, 岡本 直之, 景山 恵介1994 年 41 巻 2 号 p. 201-204
発行日: 1994/02/15
公開日: 2009/05/22
ジャーナル フリーMagnetic properties of Mn-Zn ferrites having fine grain size have been studied. The sintered fcrrite(sample A) with grain size as small as 1μm and resistivity of 2Ωm was prepared from fine powder which was broken down with media agitation milling. From the results of the measurement of core loss, the hysteresis loss of sample A was higher as compared with that of the ferrite(sample B) with grain size of 3μm and with resistivity of 10Ωm. In the high frequency range the core loss of sample A was lower than that of sample B, because of its lower eddy current loss and redidual loss.抄録全体を表示PDF形式でダウンロード (1346K)
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