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47 巻, 7 号
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阿部 正紀2000 年 47 巻 7 号 p. 704
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (66K) -
浅香 一夫, 石原 千生, 馬場 昇, 三谷 宏幸2000 年 47 巻 7 号 p. 705-710
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーAnode reactor powder cores are used to protect Thyristor Valves of HVDC (High-Voltage Direct Current)transmission systems. They must have a long life under special conditions of high frequency and high magnetic flux density. Thus, they should have the properties of low core loss, constant permeability, high saturated flux density, and excellent heat resistance.
To develop them, we studied on formation methods and compositions of uniform inorganic insulation films on each powder, and on selection and additive conditions of resin. As the results, we have developed the new anode reactor powder cores which shows specific resistivity of more than 1 Ωm, which is above twenty times of usual powder cores, and saturation flux density of more than 1T. They show scarcely increase of core loss after 4000 hours at 423 K, which means that they indicate excellent heat resistance.抄録全体を表示PDF形式でダウンロード (2965K) -
尾崎 由紀子, 植田 正輝, 藤長 政志2000 年 47 巻 7 号 p. 711-716
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーThe effect of compacting behavior of powders on the initial permeability was investigated for iron powder dust cores made from reduced iron powder and water atomized one. The initial permeability of the reduced iron powder dust core was higher than that of the water atomized one. The analysis of the compacting behavior revealed that the reduced iron powder particles were deformed more than the water atomized ones, and stretched paralell to the direction of the magnetic flux. It was indicated that the stretched shape of particles lowered an effective demagnetizing factor of the reduced iron powder dust cores, and as a result, the initial permeability was improved.抄録全体を表示PDF形式でダウンロード (5775K) -
松本 光功, 森迫 昭光, 武井 重人2000 年 47 巻 7 号 p. 717-722
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーBa and Sr ferrite thin films with M-type magnetoplumbite hexagonal structure have the great advantage available to incorporate the magnetic disk recording layer without surface protective coating due to their highly chemical stability and wear durability. This paper reports the design criteria of thin film disk media, methods of film formation of Ba and Sr ferrite, heating techniques requiredfor crystallization, the investigation of grain size control.抄録全体を表示PDF形式でダウンロード (3235K) -
五味 学, 清村 貴利2000 年 47 巻 7 号 p. 723-729
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーFerromagnetic iron oxides, typically ferrites, have attracted much interest as a promising material for next generation of electronic devices because of its broad range of electrical properties. Pulsed laser deposition (PLD) is an effective method to grow the thin films of these materials. In this review, studies on the PLD growth of the ferrite thin films were outlined. On the basis of thermodynamical consideration, criteria for low-temperature growth of good films were discussed. The PLD growth in high vacuum, so-called laser-molecular beam epitaxy, was shown to be effective to low-temperature growth of the ferrite thin films. The effectiveness was practically demonstrated through the film growth of Fe3O4, MnZn- and NiZn-ferrite with spinel structure. Room-temperature epitaxial growth of the MnZnand NiZn ferrite thin films with high quality were achieved by this technique for the first time.抄録全体を表示PDF形式でダウンロード (3204K) -
張 福春, 北本 仁孝, 阿部 正紀2000 年 47 巻 7 号 p. 730-732
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーCoNi ferrite thin films were prepared for perpendicular magnetic recording media by spin-spray ferrite-plating method. In this paper, solution conditions for CoNi ferrite plating were optimized to increase coercivity Hc⊥ and remanence ratio (Mr/Ms)⊥ in perpendicular direction to the film plane. By adjusting the deposition rate, the concentration of NaNO2 to optimize the ratio of Fe2+ to Fe3+ in the films and the concentration of CH3COONH4 to optimize pH in oxidizing solution, CoNi ferrite films with Hc⊥ of 3200 Oe and (Mr/Ms)⊥ of 0.6 were obtained without any heattreatment. Disk media prepared under the optimized solution conditions exhibited reproduced waveforms of dipluse shape and better frequency responses than that with lower Hc⊥ and (Mr/Ms)⊥.抄録全体を表示PDF形式でダウンロード (1369K) -
西村 一寛, 小原 義久, 北本 仁孝, 阿部 正紀2000 年 47 巻 7 号 p. 733-736
発行日: 2000/07/15
公開日: 2009/12/04
ジャーナル フリーMagnetite (Fe3O4) films were successfully grown at 24°C from an aqueous solutions of FeC12 into which an oxidizing solution of (1) NaNO2 + NH3 (pH-adjuster) +CH3COONH4 (pH-buffer), (2) NaNO2+NH3+NH4C1(pH-buffer), or (3) NaNO2+NH3, was added. Films of single phase Fe3O4, as revealed by X-ray diffractometry, were obtained at pH=8-9. The pH value is increased from pH=5-7 at which single phase Fe3O4 films were synthesized previously at 60°C, as predicted from theory. The deposition rates of the Fe3O4 films take maximum values of 2.3 nm/min., 11.4 nm/min., and 6.3 nm/min. when oxidizing solution of (1), (2) and (3) were used, respectively. The films grown using the oxidizing solution. (3) were smooth in surface but those grown using (1) and (2) had rough surfaces.抄録全体を表示PDF形式でダウンロード (1642K) -
杉山 明, 小林 慶三, 尾崎 公洋, 松本 章宏, 西尾 敏幸, 草加 勝司2000 年 47 巻 7 号 p. 737-741
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーPreparation of duplex phase magnetic materials, which consisted of giant magnetostrictive (Tb0.5Dy0.5)Fel.8 and zero magnetostrictive Fe-6.5mass%Si alloys was investigated. The giant magnetstrictive (Tb0.5Dy0.5)Fe1.8 powders were synthesized by the mechanical alloying (MA) method. The zero magnetostrictive Fe-6.5mass%Si alloy powders was produced by the water atomization method. The MA was performed in a planetary ball mill. These powders were consolidated at 1273 K. Each powder was filled and sintered in stratified formation in order to make the duplex phase magnetic material. However, the minimum thickness of sintered sample without breaking was 2 mm. To get thinner sintered duplex phases magnetic material, at first only the zero magnetostrictive Fe-6.5mass%Si alloy were sintered. Then the sintered compact was planed the surface to thickness of 0.2 mm. This thin plate was put on the punch in the die. The giant magnetstrictive (Tb0.5Dy0.5)Fe1.8 powders were filled up on this plate in the die to sinter at 1273 K. The thickness of this sintered sample was 0.6mm. The diffusion layer, which is expected as the buffer of the stress produced by bending, -was not observed at the interface.抄録全体を表示PDF形式でダウンロード (4125K) -
杉山 明, 小林 慶三, 尾崎 公洋, 松本 章宏, 西尾 敏幸, 草加 勝司2000 年 47 巻 7 号 p. 742-747
発行日: 2000/07/15
公開日: 2010/07/12
ジャーナル フリーAn experimental survey was carried out on the magnetostrictive properties of duplex phase magnetic materials, which consisted of giant magnetostrictive (GMS)(TbxDy1-x)Fey and mainly, zero magntostrictive alloy. In this case, duplex phase magnetic materials were produced by mechnical alloying (MA) method and subsequently, spark plasma sintering (SPS) in the state of no crack in the interface.
The results obtained were summarized as follows:
(1) As for giant magnetostrictor, (Tb0.5Dy0.5)Fe1.8 alloy induces the larger magnetostriction (λ=Δl/1) of more than 2.2×10-4 (at applied field-110kA/m)-employed as typical GMS composition hereafter.
(2) GMS/Fe-6.SSi materials show the deflective behavior in applied field under the influence of GMS's larger magnetostriction, though having a gradual change of ingredients in the interface.
(3) On the whole, the relationship between deflection (Δθ: longitudinal) and applied field (H: horizontal) is symmetrically Butterfly-type, excepting being anomalously in the initial magnetization to as-produced.
(4) In the first quadrant, the deflection (Δθ) of GMS/Fe-6.5Si materials increases linearly with the rise of applied field (H) together with less hysteresis, almost independently of Fe-6.5Si particle's morphologies.
(5) In this linear region, Δθ/ΔH is 1.1×10-4rad/kAm-1 for GMS/Fe-6.5Si, and further, may possibly be larger value for GMS combined with minus magnetostrictive (λ<0) one as Fe-14Si.抄録全体を表示PDF形式でダウンロード (1929K) -
鉄川 弘樹, 目黒 政志, 井上 誠2000 年 47 巻 7 号 p. 748-751
発行日: 2000/07/15
公開日: 2010/07/12
ジャーナル フリーThe oxidation stability of acicular Fe-Co particles in the high temperature range has been investigated using the thermogravimetry method. The rate of oxidation reaction decreases with the increase of Co content in metal particles. From the analysis of the oxidation process, the reaction mechanism of Fe-Co particles can be explained by an unreacted core model with a rate controlling process of diffusion in a continuous product layer. The oxide from the iron particle at 573 K is γ-Fe2O3, while the oxide from the Fe-Co particle is Fe3O4 or CoFe2O4 and the production of γ-Fe2O3 is suppressed. Therefore it is found that the oxidation stability in the high temperature range is improved by the addition of cobalt in metal particles.抄録全体を表示PDF形式でダウンロード (288K) -
寺澤 誠, 柿崎 浩一, 平塚 信之2000 年 47 巻 7 号 p. 752-756
発行日: 2000/07/15
公開日: 2009/12/04
ジャーナル フリーAcicular manganese zinc ferrite fine particles were made from small acicular α-FeOOH, Mn(C5H7O2)3, and Zn(C5H7O2)2. The long axis of these fine particles was oriented in parallel to the external magnetic field of 557kA/m, and then formed into multi-layered toroidal core. The green compact was sintered at 1200°C for 6 hours in air, and then cooled in a nitrogen atmosphere. The relative bulk density of the sintering body was improved from 87.0% to 90.2%. Crystallites consisted of the {110} plane were aligned along the upper plane of toroidal core of crystal-oriented manganese zinc ferrite. The initial permeability of crystal-oriented manganese zinc ferrite was 2240 at 0.1 MHz. The sample exhibited excellent high frequency magnetic properties.抄録全体を表示PDF形式でダウンロード (3699K) -
山本 節夫, 棚町 信次, 堀江 真司, 栗巣 普揮, 松浦 満, 石田 浩一2000 年 47 巻 7 号 p. 757-762
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーFerrite disk cores and laminated disk cores composed of Ferrite and Permalloy films were prepared by Spark-Plasma-Sintering (SPS) method. Soft magnetic ferrite disk core with small number of void was obtained when SPS was carried out for long time. Ferrite/Permalloy laminated disk core prepared by SPS shows high bonding strength, high saturation magnetic flux density and superior soft magnetic properties at high frequencies. This laminated disk core is one of the promising candidates for high performance new magnetic core used in inductors, transformers and magnetic heads of card reader.抄録全体を表示PDF形式でダウンロード (2955K) -
黒田 朋史, 齊田 仁, 佐藤 直義, 野村 武史2000 年 47 巻 7 号 p. 763-767
発行日: 2000/07/15
公開日: 2010/07/12
ジャーナル フリーThe effect of sintering condition, especially oxygen partial pressure in cooling step, on grain boundary chemistry in MnZn ferrite has been studied. It is found that lower partial pressures of oxgen at higher temperatures induce indistinct grain boundaries, which reduce initial permeability and electrical resistivity. The indistinct grain boundaries are caused by the dissolution of Ca2+ ion into spinet phase. Because of the dissolved Ca2+ ion, the secondary peak maximum of initial permeability appears at higher temperature, and seems to be dominated not only by Fe2+ ion but also by other dissolved cations.抄録全体を表示PDF形式でダウンロード (1995K) -
青木 卓也, 村瀬 琢, 野村 武史2000 年 47 巻 7 号 p. 768-773
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーThe effect of milling conditions on microstructures and magnetic properties of MgCuZn ferrites has been studied with reference to the effect of water. It is shown that the ferrites made by dry grinding process are lower in magnetic properties than those prepared by wet grinding or those treated by water after dry grinding. It was also found that calcium sulfate had been formed during calcination. The calcium sulfate in ferrite powders treated by water after dry grinding is hemihydrous calcium sulfate, while that without treated by water is anhydrous calcium sulfate. After sintering, calcium sulfate was segregated at the grain boundary in the case of ferrite powder treated by water after dry grinding. On the other hand, calcium sulfate was dispersed within grains in the case of that without treatment by water. This is because anhydrous calcium sulfate particles, which were hardened by hydration, are larger than hemihydrous calcium sulfate. The reasons for lower performance of dry ground powder without treatment by water are considered that much S remained in the sintered body and calcium sulfate was dispersed within grains.抄録全体を表示PDF形式でダウンロード (5832K) -
梅田 秀信, 金田 功, 村瀬 琢, 野村 武史2000 年 47 巻 7 号 p. 774-778
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーThe relaxation time of relaxation phenomenon and frequency dispersion of complex permeability have been investigated in system of MgCuZn ferrites. From the measurement of temperature dependence of imaginary part of complex permeability, the relaxation time at infinite temperature is calculated as about 10-12sec. From the analysis of frequency dispersion, the natural resonance frequency does not agree with the one calculated from Snoek's limit and initial permeability measured in the MgCuZn ferrite with relaxation phenomenon. From the consideration of the activation energy and the relaxation time, it is suggested that the relaxation phenomena by CuO substitutions in MgCuZn ferrites occur by the induced magnetic anisotropy with mutual interaction between electron movement and lattice vibration.抄録全体を表示PDF形式でダウンロード (370K) -
大井 明徳, 中野 敦之, 野村 武史2000 年 47 巻 7 号 p. 779-783
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーNiCuZn ferrites for multilayer ferrite chip components have to be sintered at a temperature lower than 930°C due to the internal Ag winding. This sintering temperature is required for higher density and larger grain growth of the ferrites which, in turn, improve its magnetic properties. Optimum composition, high purity Fe2O3, homogeneous composition of ferrite grains and addition of boron silicate glass were studied with reference to the microstructure and the magnetic properties. Therefore, significant increase of densification and improvement in magnetic properties of low temperature sintered NiCuZn ferrites were obtained.抄録全体を表示PDF形式でダウンロード (3478K) -
和田 龍一, 柿崎 浩一, 平塚 信之2000 年 47 巻 7 号 p. 784-788
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーA series of room-temperature ferromagnetic mixed oxides, Ba3Co2MnxFe24-xO41, with z-type structure, has been synthesized by high temperature solid-state reaction. Ba3Co2MnxFe24-xO41 was made from BaCO3, CoO, Mn2O3 and α-Fe2O3. The structure was determined by x-ray diffraction method; single phase with z-type structure was obtained for Ba3Co2MnxFe24-xO41(x=0, 1, 2). Frequency dependence of initial permeability of all samples was investigated. The initial permeability of Ba3Co2Mn1Fe23O41 was 13 (at 0.1 MHz), which was highest of all samples. One of the reasons is due to the change of magnetocrystalline anisotropy which caused by Mn ions and Fe ions. The other is decrease of the magnetostriction caused by Jahn-Teller effects which induced by Mn3+ ions.抄録全体を表示PDF形式でダウンロード (1774K) -
山元 洋, 前川 和也2000 年 47 巻 7 号 p. 789-795
発行日: 2000/07/15
公開日: 2010/07/12
ジャーナル フリーAn experiment was carried out to investigate the effects of Mg-organic-compound as a new reducing agent, and that of SiO2 and CaO additives, on the magnetic and physical properties of SrFe2-W type hexagonal ferrite. It was found that the magnetic properties of SrO·9.0Fe2O3 were considerably improved by adding 0.2 wt% Mg-organic-compound, 0.3 wt% SiO2, and 0.75 wt% CaO together. The optimum conditions for making magnets and some properties of typical specimens are as follows. Chemical analysis composition: Sr2+0.94Si4+0.093Ca2+0.188Mg2+0.001Fe2+1.368 Fe3+15.812O27; semisintering conditions: 1350°C×3.0h in nitrogen gas atmosphere; drying treatment condition: 200 °C×5.0 h in air; sintering condition: 1150°C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties are Jm=0.475 (1), Jr=0.437 (1), HcJ=203.88 (kA/m), HcB=177.46 (kA/m), (BH)max =34.22 (kJ/m3), Tc=503.8 (°C), HA= 1432.40(kA/m), KA=3.40×105J/m3, and nB=31.0μB, a=5.884(×10-10m), c=32.834 (×10-10m), and c/a=5.580.抄録全体を表示PDF形式でダウンロード (2821K) -
小原 学, 山元 洋2000 年 47 巻 7 号 p. 796-800
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーSr-La-Co M-type ferrite fine particles were prepared by mechanical compounding using the planetary ball-mill which was followed by heat treatment. This experiment was carried out to investigate the effect of CaO and SiO2 additives on the magnetic properties of anisotropic sintered magnets using Sr-La-Co ferrite fine particles by mechanical compounding method. The optimum conditions for making Sr-La-Co system anisotropic sintered magnets and some properties of typical specimens are as follows. Chemical composition: SrO·6.3Fe2O3 added with 2wt%La2O3 and 0.3wt%Co3O4; planetary ball-mill condition: 300 rpm × 1h; heat treatment condition: 1200°C × 4h in air, additives: 1.3wt%CaO and 0.5wt%SiO2; pressing condition: 98MPa in 800kA/m magnetic field; sintering conditions: 1170°C × 2 h; magnetic and physical properties are Jr = 0.42 T, HcJ=171 kA/m, HcB =169kA/m, (BH)max=33.7kJ/m3, Tc=453.2°C, and D=4.88 Mg/m3.抄録全体を表示PDF形式でダウンロード (2976K) -
伊藤 滋, 五十嵐 潤, 藤井 孝2000 年 47 巻 7 号 p. 801-806
発行日: 2000/07/15
公開日: 2009/05/22
ジャーナル フリーSm2Fe17Nx has been hipped to realize the excellent magnetic properties; high Curie temperature, strong uniaxial anisotropy and high saturation magnetization. Sm2Fe17Nx decomposes to SmN and α-Fe at above 600°C. Sintering of Sm2Fe17Nx is impossible under atmosphere pressure. In this study, HIP sintering and magnetic properties of Sm2Fe17N3 have been studied in terms of the possibility of practical use as a permanent magnetic material. Milled powder of Sm2Fe17N3 was charged into an aluminum capsule applying uniaxial pressure of 50MPa in nitrogen atmosphere. The hipped Sm2Fe17N3 having 92% of relative density was obtained at 450°C under 200 MPa without decomposition. The relative density obtained was larger than those of bonded magnets. Magnetic field of 4.14 MA/m (52 kOe) was applied to orientate the powder in the capsule. Giving an orientation to the specimen, the maximum magnetic properties were obtained as follows; remanent magnetization: 0.96T (9.6kG), and (BH)max: 118 kJ/m3 (14.8MGOe).抄録全体を表示PDF形式でダウンロード (2156K)
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