巻号一覧
46 巻, 1 号
選択された号の論文の17件中1～17を表示しています
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斎藤 次郎, 高橋 秀史, 関野 貴之, 西山 勝廣1999 年 46 巻 1 号 p. 3-8
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーSliding wear behavior of newly developed of magnesium base hard alloys containing magnesium borides carbon steel (SUJ2) wear studied by ring-on-block type Ogoshi wear resislance teste at sliding velocities of 3.55m/s, load of 20.6N and sliding distance of 66.6m to 600m. The new hard alloys exhibits better wear resistance and gives less than conventional magnesium alloys. The excellent wear performance of the new hard alloys are attributed to the improvement of hardness and the formation of oxides such as MgO and B2O3, which may act as lubricants during slides.抄録全体を表示PDF形式でダウンロード (3167K) -
海江田 義也1999 年 46 巻 1 号 p. 9-15
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーIn order to simulate the influence of microgravity on the reaction between gas and metallic powder, the experiments of heating the titanium wire specimens with 0.5 mm diameter by electric current in 0.5 absolute atmospheric pressure (0.5 kg/cm2) of pure nitrogen gas environment under normal gravity (g=9.8m/s2=1G) and microgravity (g=μG) using a drop shaft that enables 10 seconds duration of microgravitational condition is carried out. The influence of gravitational acceleration on the morphological changes in optical microscopic microstructures of the specimens is studied. The nitriding reaction becomes active under microgravity by temperature increase of the specimens with the heating time due to the suppression of thermal convection and the cooling effect of the nitrogen gas on the specimens is reduced. The results of the present study are explained by the gravitational acceleration effects.抄録全体を表示PDF形式でダウンロード (6146K) -
Takashi Itoh, Yoshimoto Wanibe1999 年 46 巻 1 号 p. 16-21
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーPowder morphology affects the compacting behavior as well as the packing and the fluidity of powder. A quantitative analysis was carried out by evaluating the correlation between the compacting behavior and the morphological properties of metallic powder. The compacting behavior was quantified with the equation proposed by Cooper and Eaton, which expresses the behavior with two mechanisms of rearrangement and plastic deformation of powders. The powder morphology was characterized with the particle size-shape dispersion diagram. The rearrangement behavior of powder was quantitatively related with four factors of the morphological properties by using two linear equations. The plastic deformation behavior was characterized with the packing density and the hardness of powder.抄録全体を表示PDF形式でダウンロード (401K) -
武川 淳二郎1999 年 46 巻 1 号 p. 22-27
発行日: 1999/01/15
公開日: 2009/12/04
ジャーナル フリーEnhanced sintering of molybdenum (Mo) powder through the addition of Ni and Zr was investigated. In order to obtain an uniform and fine dispertion of the additives on the surface of Mo particles, Ni and Zr were added using the nitrate solusions. The results obtained were as follows.
(1) The densification of Mo powder during sintering was markedly enhanced through the additions of Zr in conjunction with Ni, whereas through the additions of Zr alone no such enhancement occured.
(2) The sinterability of Mo powder increased with the increase of Ni.
(3) The additives composed of Ni and Zr in a mass ratio of about 4 to 1 indicated the most enhancing effect on sintering of Mo powder. For instance, Mo powder contained 0.8mass%Ni and 0.2mass%Zr was densified to near the theoretical density by sintering at 1573K for 24ks.
(4) In addition to sintering enhancement, Zr was very effective on the grain refinement of sintered Mo compacts.抄録全体を表示PDF形式でダウンロード (6026K) -
Hajime Haneda, Takamasa Ishigaki, Junzo Tanaka, Isao Sakaguchi, Noboru ...1999 年 46 巻 1 号 p. 28-35
発行日: 1999/01/15
公開日: 2009/12/04
ジャーナル フリーOxygen self-diffusion coefficients in a manganese zinc ferrous ferrite single crystals were determined at various oxygen partial pressures by means of a secondary ion mass spectrometer. Temperature dependence of diffusivity of oxide ions consisted of three parts. The characteristics at middle temperature range above 5 hPa oxygen partial pressure exhibited a behavior as an extrinsic one and was described as;
D=4.8×10-6⋅P0.35O2 exp(-137kJ/mol/RT)cm2⋅s-1
This activation energy corresponded to the barrier for the migration of oxide ions in spinel structure. The dependence of oxygen self-diffusion on oxygen partial pressure exhibited a positive sign (slope value: 0.35). This phenomenon suggests that the oxygen ions diffuse in Mn-Zn ferrite through interstitial sites above 5 hPa of the oxygen partial pressure.抄録全体を表示PDF形式でダウンロード (596K) -
羽田 肇, 磯部 光正, 石垣 隆正, 坂口 勲, 一ノ瀬 昇1999 年 46 巻 1 号 p. 36-47
発行日: 1999/01/15
公開日: 2009/12/04
ジャーナル フリーOxide ion diffusivities were evaluated in single crystals of Mg-Al-Fe-O spinel solid solutions. The single crystals were grown by a traveling solvent floating zone technique. The diffusion coefficients of oxide ions were obtained by means of a solid-gas exchange method, using 18O isotope as tracer. The secondary mass spectrometer was used to measured the oxygen diffusion profiles in solids. Some profiles was not able to be interpreted by a simple error function. These anomalies are considered to be due to oxidizing or reducing process in the single crystals during the oxygen diffusion annealing. Iron ions preferentially diffused to surface during oxygen diffusion annealing in Mg0.93Al1.24Fe0.83O4+δ-crystals, while Mg0.91Al0.72Fe1.37O4+δ-crystals have not these behaviors. The resultant diffusion coefficient of Mg0.91Al0.72Fe1.37O4+δ-crystals were divided two temperature dependence as follows;
D=2.0×10-1exp(-372(kJ/mol)/RT)cm2⋅s-1>1530K
D=1.0×10-7exp(-181(kJ/mol)/RT)cm2⋅s-1<1530K
This tendency agreed with the polycrystalline data. In these samples it is considered that the oxide ions diffuses through oxygen vacancies.抄録全体を表示PDF形式でダウンロード (2838K) -
杉本 光男1999 年 46 巻 1 号 p. 50
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (96K) -
森本 耕一郎, 石井 義成, 中山 亮治, 板倉 賢, 桑野 範之, 沖 憲典1999 年 46 巻 1 号 p. 51-56
発行日: 1999/01/15
公開日: 2010/07/12
ジャーナル フリーIt is well established that the hydrogenation-decomposition-desorption-recombination (HDDR) process can produce anisotropic Nd2Fe14B-based magnet powders having high coercivities. In this study, we investigated effects of the intermediate argon (IA) treatment, where alloys are annealed under argon atmosphere after hydrogenation in the HDDR process, on magnetic properties of Nd12.6Febal.Co17.4B6.5Zr0.1Ga0.3 magnet powders. It was found that magnetic anisotropy of magnet powders is improved with IA treatment time. On the other hand, their coercivities are decreased by the IA treatment longer than 10min. The magnetic properties of the magnet powders with diameters of 100-212μm produced through the IA treatment for 10min are as follows: Br=1.38T, HcJ=1000kA/m and (BH)max=334kJ/m3. Transmission electron microscope observation revealed that change in microstructures such as rapid growth of α-(Fe, Co) matrix, disappearance of (Fe, Co)2B and formation of a new phase (TE phase) occur in hydrogenated alloys during the IA treatment.抄録全体を表示PDF形式でダウンロード (4259K) -
橋正 好行, 大北 雅一, 三野 修嗣, 石垣 尚幸1999 年 46 巻 1 号 p. 57-61
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーA magnetically anisotropic powder behavior under compaction in magnetic field was studied in order to make a bonded magnet with high maximum energy product composed of magnetically anisotropic Nd-Fe-B powder and an epoxy resin binder. In this work, the influence of the strength and duration of magnetic field on the degree of magnetic orientation was investigated. The results show that the degree of magnetic orientation is dependent on the bulk density of magnetically anisotropic Nd-Fe-B powder in the mold during compaction in magnetic field. Magnetic field at low bulk density is necessary for high degree of magnetic orientation.抄録全体を表示PDF形式でダウンロード (4943K) -
松永 秀樹, 大北 雅一, 石垣 尚幸, 辻本 秀治1999 年 46 巻 1 号 p. 62-66
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーThermostable compression-molded bonded magnets, composed of anisotropic Nd-Fe-B powder, epoxy resin and thermosetting resin with volatile component, were developed. The influence of the thermosetting resin with volatile component on the thermostability and the mechanical strength of bonded magnets were investigated. The results show that thermal deterioration of bonded magnets is decreased by using the thermosetting resin with volatile component. Bonded magnets made by this method have a powder volume fraction and degreee of magenetic orientation of 77% and 96%, respectively. Bonded magnets with a high mechanical strength can be obtained by improvement in the compounding process.抄録全体を表示PDF形式でダウンロード (295K) -
沖本 邦郎, 和泉 克尚, 豊田 幸夫, 細川 誠一1999 年 46 巻 1 号 p. 67-71
発行日: 1999/01/15
公開日: 2009/12/04
ジャーナル フリーFor the purpose of producing ferrite part with a complicated shape which has different alignment of the ferrite crystallites, the feasibility of combined sinter joining method was studied. Disk was compacted under magnetic field of 915kA⋅m-1 and ring compacted under non-magnetic field, respectively. The two compacts was assembled into a unit and then sintered at 1150°C.
The oriented ferrite compacted under the magnetic field has dimensional anisotropy owing to sintering shrinkage. The anisotropic shrinkage, which will be capable of affecting the joining behavior, was investigated with respect to the effects of powder particle size, powder lubricant, compacting lubricant and compacting pressure before applying the magnetic field. It was found that the sintering shrinkage and degree of ferrite alignment in forming using a dry-type lubricant are largely affected by the compacting pressure before applying the magnetic field, even if the compacting pressure was several MPa or so, and that the alignment of the anisotropic compacts were similar to that of the compact consolidated under non-magnetic field. Effect of the magnetic field on joint strength of the sinter joined compact was also investigated.抄録全体を表示PDF形式でダウンロード (395K) -
細川 誠一, 豊田 幸夫, 沖本 邦郎, 和泉 克尚1999 年 46 巻 1 号 p. 72-76
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーThe influences of the molding pressure (30, 50MPa) and temperature (100-250°C) on magnetic properties of bonded magnets with Sr-ferrite powders are investigated. The coercivity of the bonded magnets is almost constant 240kAm-1 at the molding temperature of about 200°C or more and independent of molding pressure. The reason why the coercivity of bonded magnets scarcely reduced during molding is due to quasi-isostatic pressure applied for Sr-ferrite powders by resin among the powders, considered by experiments using CIP and powder epoxy resin. The reduction of coercivity of Sr-ferrite powders is caused by mixing the compound. And the reduction of coercivity corresponds with mixing torque, which relates to shapes of Sr-ferrite powders.抄録全体を表示PDF形式でダウンロード (1709K) -
増澤 清幸, 皆地 良彦, 飯田 和昌, 田口 仁1999 年 46 巻 1 号 p. 77-82
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーOrientation degree of strontium ferrite particles in a magnetic field at water-based wet-pressing stage was investigated from the viewpoint of calcining temperature and dispersant addition. In the case of no dispersant addition, the orientation degree was low especially at low calcining temperature (1150°C and 1200°C), at which the particle size was under micron. Increasing the calcining temperature, the orientation degree noticeably increased. On the other hand, we found that the orientation of the submicron sized particles was much improved by addition of calcium gluconate as a dispersant and then the orientation degree was almost independent of calcining temperature. It was predicted that calcium gluconate effectively deagglomerated submicron sized particles of strontium ferrite. Therefore addition of calcium gluconate enabled to produce high-performance ferrite magnets with both high coercivity and high remanence.抄録全体を表示PDF形式でダウンロード (5428K) -
沖本 邦郎, 和泉 克尚, 豊田 幸夫, 細川 誠一1999 年 46 巻 1 号 p. 83-87
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーFor the purpose of solving the limitations such as shape and dimension for magnetic compact fabricated by conventional anisotropic forming under magnetic orienting field, the feasibility of a new magnetic forming process was studied. Ferrite powder mixed with UV resin was compacted in the die mold and followed by alignment under the magnetic field. Effects of viscosity of UV resin and forming condition on magnetic characteristics of the compact was investigated. Maximum degree of alignment for the ferrite powder reached to 0.826. It was predicted that the proposed method had make it possible to fabricate a high performance magnet having the anisotropic alignment of the magnetic powder. The UV resin is desirable to have low viscosity, good properties such as formability and configuration stability for the compact and also parting-ability between the metal mold and the compact.抄録全体を表示PDF形式でダウンロード (345K) -
Y型フェライト電波吸収体への応用小田 喜一, 乾 哲司1999 年 46 巻 1 号 p. 88-91
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーThe electromagnetic properties of Y-type hexagonal ferrite were studied to apply it to the electromagnetic wave absorbers in the GHz band. The sintered bodies having various chemical compositions were prepared, and both the complex relative-permeability and complex relative-permittivity were measured in the frequency range of 45MHz to 20GHz. The return loss was simulated with those experimental values for the metal-backed single-layer model. Moreover, a ferrite-rubber composite absorber was fabricated with Ni2Y-type ferrite. The simulated return loss curve agreed closely with that observed experimentally. The absorber showed the matching frequency, matching thickness and -20dB absorber bandwidth being 6.7GHz, 3.71mm and 2.1GHz, respectively. It was found that Y-type ferrite was a promising material for the absorber in the GHz band.抄録全体を表示PDF形式でダウンロード (284K) -
村瀬 琢, 野村 武史1999 年 46 巻 1 号 p. 92-97
発行日: 1999/01/15
公開日: 2009/05/22
ジャーナル フリーThe excess of Fe2O3 in MgZn ferrite sintered in air easily results in a discontinuous grain growth. On the other hand, ferrites with a deficiency of Fe2O3 in the stoichiometry tend to produce a uniform microstructure irrespective of the sintering atmosphere. The firing at low Po2 is highly effective in suppressing the discontinuous grain growth, and it precipitates the magnesiowustite accompanying the inhibition of grain growth. Highly pure ferrites with excess Fe2O3 never stimulate any discontinuous grain growth and result in a uniform microstructure. The formation of precipitates and liquid phase is correlation to the extent of the grain growth behavior of MgZn ferrite.抄録全体を表示PDF形式でダウンロード (4907K) -
松谷 伸哉, 藤井 浩, 原田 真二1999 年 46 巻 1 号 p. 98-102
発行日: 1999/01/15
公開日: 2010/07/12
ジャーナル フリーWe have developed a Non-Shrinkage Ferrites “NSF” having near-net-shape by adding metallic Fe and sintered at high temperature (about 1200°C). In this work, we report low temperature (under the melting point of Ag, 960°C) sintered NSF. The control of the degree of NSF shrinkage is possible through utilizing both the expansion caused by the oxidation of metallic Fe and the complex chemical reaction allowed with NiO, ZnO, and CuO during sintering up to 920°C. In the case of low temperature sintering, high density NSF cannot be realized because non-uniform grain caused by the extreme oxidation of metallic Fe remains. It is found that addition of low-melting point oxides to the NSF permits effectively the NSF's microstructure to make uniform and compact. XRD and VSM show these NSF have the complete spinel crystal structure of ferrite. As a result, the shrinkage of low temperature sintered NSF is extremely small (-0.4%) and their magnetic characteristics are actually identical with those of conventional low temperature sintered ferrites.抄録全体を表示PDF形式でダウンロード (4401K)
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