巻号一覧
52 巻, 9 号
September
選択された号の論文の11件中1～11を表示しています
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研究
研究
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藤原 啓郎, 三木 啓至, 佃 雅司, 団野 光春, 松下 功2005 年 52 巻 9 号 p. 651-657
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスA New cold isostatic press (CIP) was applied for complex shape forming of the green compact of a roller shape with an axis. The new CIP comprises rubber mold having an inside space for filling powder, bendable pressure rubber which the rubber mold is fitted into, a case which the bendable pressure rubber is fitted into, a guide surface for pressure oil between the bendable pressure rubber and the case, and a supply channel of pressure oil which opens on a part of the guide surface which is opposite to an initial region of pressure. By using the new CIP air in powder is squeezed out not to give a bad influence on the course of pressure compacting. Results obtained by the epoch-making method of the new CIP were as follows. (1) The compact of the roller with an axis was formed on the condition that the hardness of the rubber mold was smaller than that of the pressure rubber. (2) The green density of the compact was uniform.抄録全体を表示PDF形式でダウンロード (1471K) -
國次 真輔, 西田 典秀, 冨谷 隆夫, 長江 正寛, 高田 潤2005 年 52 巻 9 号 p. 658-663
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスA homogeneous layer of molybdenum alumininosilicide Mo(Si,Al)2 with C(40) structure was made on the sample surface of molybdenum thin plate with a thickness of 0.1 mm by dip-coating technique using Al-25 mass% Si liquid at 1073 K. The layer was formed parallel to the specimen surface. Three regions with different compositions were found to be formed in the compound layer. Region A near the Mo(Si,Al)2/Mo interface had a constant composition of Mo(Si0.83,Al0.17)2.33. In region B formed on the region A, Al concentration slightly increased. A remarkable increase in Al concentration was observed in region C near the specimen surface, whereas the concentration of Mo and Si decreased. The Mo(Si,Al)2 grains had two different shapes in the compound layer: needle-like grains near the Mo(Si,Al)2/Mo interface and granular grains near the specimen surface. The growth of the compound layer was found to exhibit three stages. In an early stage the thickness of the compound layer increased linearly as the dipping time increased, indicating that the growth was a reaction-controlled process. Its growth rate in the present study was much higher than that reported so far in the dip-coating using Al liquid with saturated Si content. In a long dipping-time stage an abnormal growth of the compound layer was observed. The compound region near the Mo(Si,Al)2/Mo interface had high hardness of 1400∼1800 HV. The hardness of the compound layer decreased as the distance from the interface increased. Such a change of hardness in the compound layer was discussed in terms of shape and dense of Mo(Si,Al)2 grains.抄録全体を表示PDF形式でダウンロード (1360K) -
Takahiro Ohkubo, Tetsuo Ono, Katsuhiro Nishiyama, Susumu Niwa, Hideki ...2005 年 52 巻 9 号 p. 664-669
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスZrB2 and HfB2 were prepared by metallothermic reduction (MTR) of ZrO2, ZrSiO4, and HfO2 with Mg or Mg and MgO mixtures. We understood that the theory of function-building fine particle preparation was able to be applied to synthesize nano-atomized fine particles of ZrB2. ZrB2 can also be obtained directly from mixture of ZrSiO4, B2O3, and Mg by MTR method. This sample has no borides such as silicon boride except for ZrB2. Therefore, this result shows the possibility to obtain ZrB2 easily from natural source. In addition, HfB2 can also be synthesized by MTR method using HfO2 which was calcined over 750°C.抄録全体を表示PDF形式でダウンロード (1390K) -
秋山 裕臣, 菅又 信, 金子 純一2005 年 52 巻 9 号 p. 670-675
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスWith a purpose of obtaining materials of high specific strength at room and high temperatures, Al-8mass% Mg alloy powder was mechanically alloyed with addition of metal oxide (B2O3, Sc2O3, TiO2, SrO, CeO2) and metal silicide (CrSi2, TiSi2, ZrSi2, WSi2, MoSi2) powders. Solid state reactions during mechanical alloying (MA) and subsequent heating were studied. The MA powders were consolidated to the P/M materials by vacuum hot pressing and hot extrusion, and their structures and mechanical properties were studied.
All added oxides but TiO2 were decomposed during heating of MA powders, and aluminide compounds and spinel (MgAl2O4) were formed. All added silicides were only partially decomposed and Mg2Si was formed during heating of MA powders. The P/M materials of Al-Mg-oxide systems are harder and less ductile than those of Al-Mg-silicide systems. The highest hardness of 237 HV was obtained on the Al-Mg-B2O3 P/M material. The P/M material of Al-Mg-CrSi2 showed the highest tensile strength of 578 MPa.抄録全体を表示PDF形式でダウンロード (1197K)
特集 磁性材料の新しい物質とプロセス技術の新展開
総報
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山崎 陽太郎2005 年 52 巻 9 号 p. 678
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスPDF形式でダウンロード (117K)
研究
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山元 洋, 眞鍋 健二, 大村 正志2005 年 52 巻 9 号 p. 679-684
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスAn experiment was carried out to investigate the effect of Ba-Stearate as a reducing agent on the magnetic and physical properties of SrFe2-W type hexagonal ferrite. It was found that the magnetic properties of SrO · 8.5Fe2O3 were improved by adding 0.3 wt% of Ba-Stearate, 0.3 wt% of SiO2, and 1.25 wt% of CaCO3 together. The optimum conditions for making magnets were as follows. Composition: SrO · 8.5Fe2O3 added with 0.3 wt% of Ba-Stearate, 0.3 wt% of SiO2, and 1.25 wt% of CaCO3. Semisintering condition: 1350°C×4.0 h in nitrogen gas atmosphere, Drying condition: 180°C×2.5 h in air, Sintering condition: 1160°C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties of a typical sample were Jm=0.48 (T), Jr=0.44 (T), HcJ=191.9 (kA/m), HcB=187.5 (kA/m), (BH)max=32.9 (kJ/m3), Tc=489 (°C), HA=1350 (kA/m), KA=3.10 (×105 J/m3). The lattice constants of this compound were a=5.896 (×10-10 m), c=32.77 (×10-10 m), and c/a=5.558.抄録全体を表示PDF形式でダウンロード (1045K) -
山元 洋, 磯野 正樹2005 年 52 巻 9 号 p. 685-690
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスSingle phase Sr-Pr-Co M-type ferrite fine particles were prepared by controlling the chemical coprecipitation method and subsequent heat treatment. The chemical reagents used for this experiment were SrCl2 · 6H2O, FeCl3 · 6H2O, PrCl3 · 7H2O and CoCl2 · 6H2O. The chemical coprecipitation composition were chosen according to the formula {(SrO) · n/2(Fe2O3)}100-x-y(Pr2O3)x(CoO)y, where n was fixed at 7.0, x was varied between 1.0 and 12.0, y between 2.0 and 10.0. A water solution containing Sr2+, Fe3+, Pr3+ and Co2+ was poured into a solution of NaOH (pH=13.0).
The precipitated products were boiled at 100°C for 2 h, and they were carefully washed with pure water for 24 h. The washing was repeated 5 times and the products were then filtered and dried at 80°C for 12 h. The obtained fine particles were heated at a temperature between 950 and 1100°C for 2 h in air to get single phase Sr-Pr-Co M-type ferrite fine particles. The most prominent magnetic properties have been observed for the sample with the preparation composition of {(SrO) · 3.5(Fe2O3)}89.0(Pr2O3)5.0(CoO)6.0; they are as follows: σs=84.0×10-6 Wb · m/kg (66.8 emu/g), σr=43.7×10-6 Wb · m/kg (34.7 emu/g), HcJ=528.8 kA/m (6.65 kOe), α (σr)=-0.18 %/°C, α (HcJ)=0.07 %/°C and Tc=459°C.抄録全体を表示PDF形式でダウンロード (725K) -
中川 貴, 高田 幸生, 祐谷 将人, 福田 泰成, 仁谷 浩明, 橘 武司, 島田 武司, 川野 眞治, 江村 修一, 山本 孝夫2005 年 52 巻 9 号 p. 691-699
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスX-ray absorption fine structure (XAFS), neutron diffraction and anomalous X-ray scattering at Fe-K edge experiments were performed to determine site distribution of iron and cobalt irons in Co2Z-type barium ferrite (Ba3Co2Fe24O41). The atomic coordinates and structure parameters of Ba3Co2Fe24O41 obtained from Rietveld analysis of neutron diffraction well agreed with those of anomalous X-ray scattering. The valences of iron and cobalt ions determined from the results of X-ray absorption near edge structure (XANES) were consistent with the magnitudes of magnetic moments of iron and cobalt ions estimated from the Rietvelt analysis of neutron diffraction. The site occupancy of cobalt ion evaluated from extended X-ray absorption fine structure (EXAFS) analysis at Co-K edge coincides that of the results of neutron diffraction analysis. These facts compensated for the certainty of the respective studies and showed that these experimental techniques were valid for the structural analysis of a material containing elements to which atomic number were adjacent.抄録全体を表示PDF形式でダウンロード (1018K) -
森 克彦, 中山 亮治, 森本 耕一郎2005 年 52 巻 9 号 p. 700-705
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスFully dense magnets were prepared by hot pressing of the hydrogenation-decomposition-desorption-recombination (HDDR)-processed powders, and they had very fine microstructures. The typical magnetic properties of the HDDR hot pressed magnet with the composition of Nd13.0Fe62.9Co17.4B6.2Zr0.1Ga0.4 were Br=1.26 T, HcJ=969 kA/m and (BH)max=279 kJ/m3. The magnetic properties and the surface morphology of the machined HDDR thin hot pressed magnets were investigated. The performance of the machined thin hot pressed magnets hardly depended on their thickness, and that of high coercivity magnets with the composition of Nd12.4Dy0.6Fe74.5Co5.8B6.2Zr0.1Ga0.4 is the same because of their fine microstructures. Furthermore, the thin hot pressed magnets hardly depended on damage by surface roughness. We investigated the long-term stabilities. As a result, the total irreversible flux loss of high coercivity hot pressed magnet with the composition of Nd12.6Dy0.6Fe58.8Co20B6.2Zr0.1Ga0.4Al1.5 at 423 K was -1.3% after 1000 hours. The HDDR hot pressed magnets make it possible to stabilize the magnetic properties of thin Nd-Fe-B magnets because of their very fine microstructure.抄録全体を表示PDF形式でダウンロード (1221K) -
沖本 邦郎, 黒田 智孝, 小路 和弘, 浦岡 秀隆, 木下 浩光2005 年 52 巻 9 号 p. 706-711
発行日: 2005年
公開日: 2006/04/28
ジャーナル オープンアクセスThe magnetic product with different alignment of the crystallites produced by conventional magnetic alignment pressing is restricted in shape and size. This paper presents two methods to solve this problem. Both methods used a compound of Sr-ferrite powder mixed with a MIM binder. One method was the combined sinter joining of a disk and ring. The inner disk was compacted under a magnetic field and the ring was compacted under a non-magnetic field. In this method, a different mixing ratio of the same kind of MIM binder was used for the disk and the ring. The two compacts were assembled into a unit and then sintered at 1225°C after debinding. The other method was a two-step integration forming process. The MIM binders used in this method were different than that used in the combined sinter joining. As the first step, the inner disk was compacted under a magnetic field using a compound of a high-melting-point MIM binder. As the second step, the compound was mixed with a low-melting-point MIM binder and then poured into the circumference of the inner disk compact under a non-magnetic field to complete the integration. The integrated compact was debinded and then sintered at 1225°C. The joint strength between the orientated and non-orientated parts and also the magnetic characteristics of the orientated part of the sintered Sr-ferrite were investigated for both methods. The joint strength of the sintered Sr-ferrite compact obtained by the two-step integration forming process was superior to that obtained by the sinter joining. The maximum joint strength obtained by the two-step integration forming process was 20.2 MPa.抄録全体を表示PDF形式でダウンロード (982K)
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9999 年 52 巻 9 号 p. 713
発行日: 9999年
公開日: 2006/07/28
ジャーナル オープンアクセスPDF形式でダウンロード (354K)
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