巻号一覧
45 巻, 10 号
選択された号の論文の20件中1～20を表示しています
- |<
- <
- 1
- >
- >|
-
Yoichi Okamoto, Hiroshi Inai, Jun Morimoto1998 年 45 巻 10 号 p. 905-908
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーThermoelectric properties of the Si doped SiC were measured. It is intended to reduce the thermal conductivity by addition of isoelectric element Si. Measurements of electrical resistivity, thermoelectric power and thermal conductivity were made on SiC thermoelectric semiconductor as a function of both Si doping concentration (over the range of 1.0 wt.%-40.0 wt.%) and temperature (from room temperature to 750°C). Measurements of Hall coefficient, X-ray crystallography and EPMA were also made on these samples. The thermal conductivity decreases with increase of Si concentration. At Si concentration of 40.0 wt.%, minimum thermal conductivity reached to 13 W/mK. The figure of merit Z was calculated from electrical resistivity, thermoelectric power and thermal conductivity. The maximum value of the figure of merit reaches 2×10-4K-1 at 750°C and Si concentration of 40.0 wt.%.抄録全体を表示PDF形式でダウンロード (329K) -
上ノ薗 聡, 宇波 繁, 小倉 邦明, 中野 善文1998 年 45 巻 10 号 p. 909-914
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーThe solute carbon content and the ratio of pearlite in the sintered steel increased and the free graphite content and the sulfur content in the sintered steel decreased with the increase in hydrogen content in the sintered atmosphere during the sintering of green compact made of the iron powder containing sulfur, copper powder and graphite powder, resulting in the deterioration of machinability of the sintered steel.
The amount of decrease in sulfur content during sintering was roughly the same as that calculated, on the assumption of hydrogen reduction of FeS in an equilibrium state.
The Auger spectrum of the iron powder containing sulfur indicated that FeS segregated on the surface of the iron powder. The dilatometry study indicated that the carbon diffusing rate during sintering green compact containing iron powder with sulfur was smaller than that during sintering green compact containing commercially pure iron powder.
These results showed that the free graphite was formed by incomplete carbon diffusion during sintering due to FeS on the surface of the iron powder with sulfur.抄録全体を表示PDF形式でダウンロード (2490K) -
鷲見 新一, 水谷 芳樹, 阿部 利彦1998 年 45 巻 10 号 p. 915-919
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーPlasma activated sintering (PAS) is a kind of hot pressing method. This sintering method is usually for powder sintering. But, it is very effective method for bonding of refractory metals to refractory metals such as tungsten, too. Purpose of this research is to make the ion gun parts (arc chamber) of ion implantation devices by bonding method. Usually, molybdenum is used for the parts. With increasingly high integration in IC memory, the problem of contamination of wafer due to molybdenum arose and therefore the parts made of tungsten are preferred by the industries. However, tungsten is too hard to be formed into the parts by conventional machining process.
The bonded joints of tungsten in the different bonding conditions (temperature, pressure, without interlayer, with interlayer of tungsten or tantalum powder) were evaluated by an optical microscope, an ultrasonic imaging and four point bending test. As a result, bending strength of the joints with interlayer of tantalum powder, tungsten powder and without any interlayer was measured to be about 400, 200 and 100MPa, respectively.抄録全体を表示PDF形式でダウンロード (3065K) -
廣瀬 徳豊, 浅見 淳一, 棚木 敏幸, 湯浅 真, 関根 功1998 年 45 巻 10 号 p. 920-925
発行日: 1998/10/15
公開日: 2010/07/12
ジャーナル フリーRelationships between Young's modulus, shear modulus, Poisson's ratio and porosity of sintered irons have been studied by an acoustic pulse method at varying of pore shapes, sizes and distributions. The pore shapes, sizes and distributions were changed by using reduced iron powder, atomized iron powder, sieved atomized iron powder, and mixed powder of carbonyl iron powder and atomized iron powder, or by the process of re-compacting and resintering.
In all case, the Young's modulus, the shear modulus and the Poisson's ratio decreased with increasing of porosity. At the same porosity, spherical and fine pores increased the Young's modulus and the shear modulus, decreased the Poisson's ratio by comparison with irregular and coarse pores. The Young's modulus, the shear modulus and the Poisson's ratio increased as pore surface becoming smooth.
In case that pore shapes are similar and pore sizes are different, the Young's modulus and the shear modulus having fine pores are higher than that having coarse pores. Although pore shapes, sizes or distributions of sintered irons were different, at the same sintering conditions the Poisson's ratios were nearly equal at the same porosity (<0.2).抄録全体を表示PDF形式でダウンロード (6598K) -
木村 修, 松本 雅史, 坂倉 光男1998 年 45 巻 10 号 p. 926-930
発行日: 1998/10/15
公開日: 2009/12/04
ジャーナル フリーThe Z type magnetoplumbite ferrite with the composition of 2CoO.3Ba0.5Sr0.5O.10.8Fe2O3 was reported to reveal enhanced dispersion frequency. This paper aims to prepare the highly crystal oriented ferrite, by using a hot-forging technique. The hot-forged samples revealed the orientation degree of more than 90 percent and their permeabilities ranged from 30 to 40. Especially, magnetic losses of the samples hot-forged in an oxygen atmosphere were highly low. The maximum μQ product at 300 MHz reached 600, which was three times of the value of the crystal-oriented sample prepared in the Philips Laboratory.抄録全体を表示PDF形式でダウンロード (3484K) -
藤原 幸男, 滝野 貢一1998 年 45 巻 10 号 p. 931-936
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーOn the preparation of the raw powder of the tantalum solid electrolytic capacitor, the effects for the propertiy of treated powder of particle size and composition of PMMA binder and spray treatment has been studied with the proposed frequency difference distribution method. This method is expresed as the difference in frequency of particle size distribution between raw and treated powder.
It was found that the mean particle diameter of the treated powder using the binary system of PMMA binder (8μm-1.25%, 1.5μm-0.75%) together with spray pre-treatment is the smallest.
The binary system of PMMA binder(8μm-1.25%, 1.5μm-0.75%) is suggested as optimam composition of PMMA binder for the grinding and homogeneity of raw powder. It was shown that the proposed frequency difference distribution method is useful for the analysis of preparation mechanism of the raw powder.抄録全体を表示PDF形式でダウンロード (1913K) -
草加 勝司, 鈴木 智也, 近藤 鉄也1998 年 45 巻 10 号 p. 937-943
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーA fundamental study was made on the AC magnetic properties and core loss of the two PM stainless steels with some residual pores. In this case, powder particle size and sintering conditions (1373-1573K×20-240min) were employed as parameters to the residual pore morphologies of sintered materials, as seen in the previous report.
The results were summarized as follows:
(1) The maximum flux density (Bm) and specific permeability (μa) wholly depend on the frequency (∝f-1/2), owing to the penetration depth of field.
(2) As for a given frequency, μa complicatedly varies with sintered density under the reciprocal influence of DC magnetic properties and electrical resistance.
(3) The DC relationship between the maximum permeability (μm) and sintered density is fairly held on the AC one in the low frequency region, as a function of powder particle size and sintering conditions.
(4) At higher frequency, μa and Bm (almost directly proportional to μa) show the maximum value in. the critical sintered density, as the case may be.
(5) The core loss behaves apparently as well as μa in the relation to sintered density and, consequently, is enhanced with the increase of Bm and reduced with the increase of electrical resistivity (ρ).抄録全体を表示PDF形式でダウンロード (451K) -
新宮 秀夫1998 年 45 巻 10 号 p. 946
発行日: 1998/10/15
公開日: 2009/12/04
ジャーナル フリーPDF形式でダウンロード (78K) -
橋井 光弥1998 年 45 巻 10 号 p. 947-951
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーA study was made on the identification of change in structure of the Fe50Al50 powders during mechanical alloying. The powders were produced by milling a mixture of pure Fe and pure Al powders with molar ratio 50:50. A dry tumbler ball milling was used.
In the X-ray diffractions, the peaks of the Fe and the Al phases became weak with milling time and the powders showed the same patterns as a case of supersaturated solid solution, α-Fe(Al), after 1800ks milling. Scanning electron microscope observations showed that the difference of each layer, the contrast of the back scattered electron micrograph, was diminished as milling time. The particles became large and lamellar in the initial milling stage. The powder became very fine (average particle size<5μm) and approximately spherical after 1800ks. A single phase of FeAl were formed by milling 1800ks and annealing at 1200K.抄録全体を表示PDF形式でダウンロード (3884K) -
杉山 明, 小林 慶三, 尾崎 公洋, 西尾 敏幸, 松本 章宏1998 年 45 巻 10 号 p. 952-957
発行日: 1998/10/15
公開日: 2009/12/04
ジャーナル フリーThe formation process of Mg2Si based thermoelectric composite made by mechanical alloying was investigated.
The MA was performed in a planetary ball mill using three elemental powders. The powders were prepared by the mixing of Mg2Si, Mg2Si-xmass%SiC(x=4, 8) and Mg2Si-xmass%FeSi2 (x=20, 40, 60, 80, 100). The structural evolution during milling was detected by X-ray diffraction(XRD). The heat treatment was monitored by differential scanning calorimetry(DSC). Microstructural changes were mainly investigated by means of scanning electron microscopy(SEM) and optical microscopy(OM).
The formation of the Mg2Si phase is observed after milling for 1080ks under At atmosphere. But the milling time to form Mg2Si became shorter by milling with including another element such as Fe, Si, N and SiC. The structure of Mg2Si milled under N2 atmosphere became most fine. For Mg2Si-xmass%FeSi2 including less than 60mass%FeSi2, the phase of Mg2Si, FeSi, Fe and Si were observed in the powder milled after 360ks. On the other hand, for Mg2Si-80mass%FeSi2, the phase of Mg2Si and FeSi was not observed but Fe and Si was only observed independent on milling time.抄録全体を表示PDF形式でダウンロード (1935K) -
祝迫 恭, 相澤 龍彦, 山本 淳, 太田 敏隆1998 年 45 巻 10 号 p. 958-961
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーBulk Mechanical Alloying (BMA) is proposed to produce p-type Bi2Te3-Sb2Te3 thermoelectric materials with large yield and without any contamination. Because of the solid-state alloyment through this process, no melting nor solidification process is necessary to yield the targeting composition of this type of thermoelectric materials.
Furthermore, hot pressing is applied for densification by varying both the pressure and the holding temperature. Process parameter dependency of thermoelectric properties is investigated for three different BMA samples.抄録全体を表示PDF形式でダウンロード (3299K) -
橋本 勝, 大槻 徴, 石原 慶一, 新宮 秀夫1998 年 45 巻 10 号 p. 962-964
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーStarting from the mixture of elemental powder mixtures, we produced bulk nanoscale Fe/Ag multilayers by the repeated press-rolling method. The average thikness of this sample was 5nm for Fe and 8nm for Ag. This sample exhibited the CIP-MR of 8.5 % at 77 K.抄録全体を表示PDF形式でダウンロード (1625K) -
小林 慶三, 尾崎 公洋, 杉山 明, 西尾 敏幸, 松本 章宏1998 年 45 巻 10 号 p. 965-968
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーMg-10at%B, Mg-20at%B, Mg-60at%B, Mg-75at%B and Mg-20at%B-5at%C were synthesized by mechanical alloying (MA) of Mg powder, boron powder and graphite powder using a vibrational ball milling in argon gas atmosphere for 720ks. Mg-10at%B, like Mg, was agglomerated into a mass by continuous rolling during MA process. Boron addition was effect to produce powder, but the contamination of Fe from the vessel and balls increased with increasing boron content in the MA powder. Since Mg-20at%B synthesized by MA was very fine powder, it was able to consolidate at 573K under a pressure of 195MPa by pulsed current sintering process. The sintered body of Mg-20at%B has a homogeneous microstructure, a density of 1.82g/cm3 and a hardness of 90Hv. In case of Mg-20at%B-5at%C, hard particles were obtained during the MA process and changed into other phase during the sintering process.抄録全体を表示PDF形式でダウンロード (287K) -
瀧田 朋広, 五十嵐 廉, 土肥 義治1998 年 45 巻 10 号 p. 969-973
発行日: 1998/10/15
公開日: 2009/12/04
ジャーナル フリーFine-grained sintered molybdenum alloy dispersed with 1.6mol% (1.0mass%) TiC was prepared by mechanical alloying and hot isostatic pressing. The mixture of fine molybdenum powder with grains measuring 20nm in diameter and TiC-particles, prepared by mechanical alloying, was sintered at 1570K for 10.8ks under 147MPa. Density of the sintered alloy was 10.1Mg/m3 (99.5% relative density); grain size of the molybdenum and the particle size of TiC in the sintered alloy were 0.4μm and below 0.2μm, respectively.
Grain growth of the alloy was measured to estimate stability of the fine-grained microstructure at high temperatures. Fine grains measuring 2μm in diameter were remained after heating at 207OK for 3.6ks. (Ti, Mo)C1-x was formed at the interface of the molybdenum and TiC-particles, and grains of molybdenum grew to 4μm in diameter after heating at 2270K for 3.6ks. After heating at 247OK, many voids and traces of liquid phase were observed at the grain boundary.抄録全体を表示PDF形式でダウンロード (4331K) -
瀧田 朋広, 五十嵐 廉, 土肥 義治, 平岡 裕1998 年 45 巻 10 号 p. 974-980
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーIn order to improve both fracture strength and resistance to embrittlement at low temperature, fine-grained sintered molybdenum alloys dispersed with fine TaC, TiC, ZrC or HfC particles of 0.4-1.6mol% were prepared by mechanical alloying (MA) and hot isostatic pressing (HIP). The mixtures of fine molybdenum powder with grains measuring 20nm in diameter and carbide particles prepared by MA, were sintered at 1570K for 10.8ks under 147MPa. The sintered alloys had relative densities of over 99% and grain sizes of 0.2-10μm. The low-temperature fracture strength and ductile-to-brittle transition temperature (DBTT) were evaluated by three-point bending test at 77K to 360K. The following results were obtained.
(1) The low-temperature fracture strength was increased and DBTT was decreased by dispersion of carbides in the sintered alloys prepared by MA and HIP.
(2) The sintered alloy dispersed with TaC has a high fracture strength of 1880MPa and a low DBTT of 156K.
(3) The sintered alloys were strengthened by carbide dispersion and grain refining, though the former effect is much effective.
(4) The intergranular fracture surface was predominant in the sintered alloy dispersed with TaC and pure-molybdenum, while the transgranular fracture surface was predominant in all other sintered alloys.抄録全体を表示PDF形式でダウンロード (5269K) -
新見 義朗, 岩津 修1998 年 45 巻 10 号 p. 981-985
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーA new oxide dispersion strengthened (ODS) alloy powders were developed by the application of a novel process which is the combination of dual stages such as (1) mechanical alloying of the metal powder with various metalalkoxides in the air atmosphere and heat (2) treatment in a hydrogen atmosphere which followed stage (3) operation. By this process very fine oxide particles were formed and dispersed in the metal matrix, and consequently the metal matrix was strengthened remarkably. Moreover, among various ODS alloy powders obtained by this process, only Al2O3-dispersion strengthened (DS) alloy powder showed very superior sinterability. This phenomenon was able to be interpreted by the thermal stability of the excess dislocations introduced in the metal matrix by mechanical alloying. It was also found that sintering of ODS alloy powders except for Al2O3-DS alloy powder which had poor sinterabilities was accelerated by undergoing pre-sintering treatment in the air atmosphere prior to ordinary sintering.
Especially, from Al2O3-DS alloy powder which showed superior sinterability the application to the porous gasdiffusional electrode in the usage at high temperature (Ni-Al2O3), or production of the large billet for the hevy electric parts (Cu-Al2O3) might be expected.抄録全体を表示PDF形式でダウンロード (5139K) -
橋本 等, 阿部 利彦1998 年 45 巻 10 号 p. 986-989
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーMechanical alloying process, especially conducted by ball milling of metal powders, shows poor reproducibility, since we have few indices adequate for the mathematical description of the process. Energy consumption by the plastic deformation of metal powder particles in the mechanical alloying process can be a good index for the mathematical description. However, it is much difficult to measure the energy consumption only by the plastic deformation of metal powder particles. In this study, the authors tried to trace the motion of individual milling balls in a tumbling ball mill during ball milling of a metal powder, by using a three-dimensional model simulation based on discrete element method. From the motion of individual balls calculated by the simulation, frequency of collision event as well as distribution of impact velocity were estimated as a function of ball filling ratio, J. As a result, the motion of balls and therefore the distribution of impact velocity were affected signifficantly by the ball filling ratio. Especially, the frequency of collision event having higher impact velocities shows an maximum at J=0.5. This means that the plastic deformation of the metal particles is most promoted at J=0.5 if the plastic deformation requires higher impact velocity.抄録全体を表示PDF形式でダウンロード (310K) -
湯浅 栄二, 河村 忠治, 田村 政臣1998 年 45 巻 10 号 p. 990-994
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーTitanium and boron powders were mixed with various contents of molar ratio Ti/B=1/2 to aluminum powder and then the mixture was mechanically alloyed for various milling times. Aluminum phase super-saturated with titanium and boron is formed by the mechanical alloying for belonged milling time and the crystalline size of α-Al phase in the powder particle with high Ti/B content becomes to nanometer order. Vickers hardness of the mechanically alloyed powder particles increases with milling time and of Ti/B contents. Al-5mass%Ti and Al-20mass% (Ti/B) powders mechanically alloyed for 108ks were heat-treated for various times at 723-873K in argon atmosphere. When the Al-20mass%(Ti/B) powder was heat-treated at temperature range of 723-823K, the age-hardening phenomenon occurs and Vickers hardness of the particles becomes to higher.抄録全体を表示PDF形式でダウンロード (1962K) -
湯浅 栄二, 河村 忠治, 杉山 公章1998 年 45 巻 10 号 p. 995-999
発行日: 1998/10/15
公開日: 2009/05/22
ジャーナル フリーA quasi-crystalline Al65Cu20Fe15 powder prepared from alloy cast rapidly solidified by metal-mold casting, and then it was mixed to aluminum powder with various volume fractions by mechanical milling. The powder milled for above 50ks made homogeneous dispersion of quasi-crystalline phase with particle size less than 1μm. The powder was hot-pressed under various conditions and then its features of consolidation were examined by the observation of microstructure and fracture strength in 3-point-bending of the compacts. When the milled powder was hot-pressed at higher compacting temperature than 673K for 3.6ks under pressure of 600MPa, the compact became to dense. Hardness of the obtained compact increases and its fracture strength decreases with increasing volume fraction of quasi-crystalline particles. Intermetallic compound Al7Cu2Fe forms in the interface of aluminum matrix and quasi-crystalline particle.抄録全体を表示PDF形式でダウンロード (3150K) -
磯西 和夫, 荻津 知也1998 年 45 巻 10 号 p. 1000-1006
発行日: 1998/10/15
公開日: 2009/12/04
ジャーナル フリーMechanical alloying (MA) of Ti-37.5mol%Si composition powder mixture (stoichiometric composition of Ti5Si3 intermetallic compound) and synthesis of Ti-silicides by milling and heat treatment of MAed powders were investigated. The formation of TiSi and TiSi2 phase were observed by milling over 540ks, but stoichiometric phase, Ti5Si3, was not formed only by milling. Fully MAed powder (more than 1800ks) changed to almost Ti5Si3 single phase after DTA runs up to 1173K. On the other hand, in the case of short period MAed powders, TiSi and TiSi2 were also formed during DTA runs in addition to the Ti5Si3.
We tried to make a dense compact using the vacuum hot pressing technique. Relative density of hot pressed compact was 99.7% of theoretical density. The hot pressed compact showed high micro-Vickers hardness more than HV 1300 and KIC value of 1.46MPa⋅m1/2. Fracture toughness of the compact exceeded the value of arc melted material, 1.19MPa.m1/2.抄録全体を表示PDF形式でダウンロード (5722K)
- |<
- <
- 1
- >
- >|