巻号一覧
58 巻, 4 号
April
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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鈴木 裕之, 門野 裕一, 黒木 英憲2011 年 58 巻 4 号 p. 201-206
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスA non-aqueous slip system for ultra fine WC powder (100 nm) is developed. Addition of non-ionic surfactant makes possible to disperse WC powders in alkane liquid (heptane), although the suspension is meta-stable, namely, the WC particles sediment gradually with time, because the density of WC is much higher than that of the medium. In such meta-stable slip systems, a lower ultimate sediment height in gravitational sedimentation corresponds to good dispersing state. A slip prepared by planetary ball milling and compacted by High-speed Centrifugal Compaction Process achieved packing density of 55 %.抄録全体を表示PDF形式でダウンロード (958K) -
Masahiro Katoh, Kenji Hayashi, Toshiharu Araki, Masayoshi Yoshida, Mas ...2011 年 58 巻 4 号 p. 207-213
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスAs the starting material of molybdenum manufactured by powder metallurgy, molybdenum powder is used. To investigate the elution in water of the molybdenum powder used as a raw material, the molybdenum elution was analyzed by ion chromatography and X-ray photoelectron spectroscopy (XPS). It was clarified that the elution based on MoO42- takes place as determined by ion chromatography. Results of the surface measurement by XPS revealed that, the molybdenum oxidized in air on the surface exists mainly as molybdenum (VI) oxide (MoO3), which is the most stable oxide. The molybdenum (VI) oxide elutes promptly in water compared with the metal powder. The oxide on the molybdenum metal surface, which was assumed to be eluted promptly, became thin, and the elution was repeated again by oxidation in water through molybdenum (IV) (MoO2), (V) (Mo2O5) and (VI) oxides, and the solution was clarified to elute through molybdenum (VI) oxide.抄録全体を表示PDF形式でダウンロード (680K) -
矢倉 孟, 高岡 勝哉, 加藤 将樹, 廣田 健, 藤井 利徳2011 年 58 巻 4 号 p. 214-219
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスSynthesis of dense composite materials with the compositions of Al2O3/TiN=100/0∼90/10 vol% has been attempted directly from Al2O3/Ti mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). Fine Ti powders (0.3 μm in diameter) with a small amount of TiN0.3 phase were prepared by thermal decomposition of fine TiH2 powders at 400°C for 3.6×103 s in a vacuum, followed by thermal treatment in N2. Then, Al2O3/Ti mixed powder compacts with homogeneously dispersed Ti particles were fabricated and then HIP-sintered. During the first stage of HIPing [1350°C/6 MPa/3.6×103 s], solid/gas reaction between Ti and N2, in which both were contained in the powder compacts, was introduced to form TiN. Then, after the successive second stage of HIPing [1350°C/196 MPa/7.2×103 s], the most of sintered composites consisting of Al2O3 and TiN phases reached to a higher relative density than 98.5 % with closed pores, nevertheless a capsule-free HIPing. Dispersion of TiN particles (0.30∼0.35 μm) just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (σb), Vickers hardness (HV), and fracture toughness (KIC) have been evaluated as a function of TiN content.抄録全体を表示PDF形式でダウンロード (1264K)
受賞記念講演
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藤川 隆男, 真鍋 康夫2011 年 58 巻 4 号 p. 220-224
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスHot Isostatic Pressing (HIP) of ceramics has been recognized as an ideal process to produce fully dense and highly reliable parts in the course of the application to ferrite magnetic recording heads, alumina cutting tool inserts, and automobile engine parts made of silicon nitride. Usually, these parts are processed by the so-called capsule-free method in which the processed parts are directly exposed to the pressure medium gas. In this case, some interactions between the processed material and the gas may occur and this phenomenon has to be carefully considered for some nitrides and oxides. Therefore, the influence of the surrounding gas as an atmosphere is discussed from the viewpoint of thermo-dynamics. Three practical methods to create the desired atmosphere are described and some examples in the application are given for silicon nitride, superconductive ceramics and calcium carbonates. In addition the development of the HIP equipment which can create desired atmosphere will be briefly reviewed.抄録全体を表示PDF形式でダウンロード (764K)
特集：メカニカルアロイングによる材料開発
総報
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石原 慶一2011 年 58 巻 4 号 p. 226
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスPDF形式でダウンロード (93K)
研究
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大野 卓哉, 久保田 正広2011 年 58 巻 4 号 p. 227-232
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスTi-x HAp (x=10, 20 and 30 mass%) composite powders were synthesised by mechanical alloying (MA) using a vibrational ball mill, and MAed composite powders were consolidated into bulk composite materials by spark plasma sintering (SPS). Effects of MA conditions on the hardness and constituent phase of the MAed powder and SPS materials were investigated by hardness measurements and X-ray diffraction (XRD), respectively. No decomposition of HAp in the Ti-HAp composite powders was observed, whereas formation of CaO was observed in all the SPSed materials. In addition, formation of TiC occurred in the Ti-10 and 20 HAp SPSed materials. On the other hand, both CaTiO3 and TiN was formed in the Ti-30 HAp SPSed materials. The hardness of the Ti-HAp SPSed materials fabricated from the 0.5, 1 and 2 h MAed powders were higher than that of the pure Ti SPSed materials fabricated from the none MAed powder. A maximum value of Vickers hardness was 1101 HV when the Ti-20 HAp SPSed material was fabricated from 1 h MAed powder.抄録全体を表示PDF形式でダウンロード (1636K) -
森下 翔, 中山 博行, 尾崎 公洋, 小林 慶三2011 年 58 巻 4 号 p. 233-236
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスFe-48at%Cr powder was synthesized by mechanical alloying (MA) of Fe powder and Cr powder using rapid-rotation type planetary ball mill. Homogeneous MA powder was obtained for only 600 s milling at 900 rpm of orbital speed while it had taken for over 360 ks to homogenize them at 200 rpm. The obtained powder had a crystal structure of bcc lattice and contained no brittle phase such as σ phase. The MA powder was sintered by a pulsed current sintering and completely condensed above 1000 K. The sintered Fe-48at%Cr alloy also has no σ phase. Hardness of the sintered body is Hv 380 and there was no crack around the indentation for Vickers hardness.抄録全体を表示PDF形式でダウンロード (753K) -
青木 翔, 久保田 正広2011 年 58 巻 4 号 p. 237-242
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスIn order to fabricate Mg-based composite powders with high hardness and hard magnetic properties, pure magnesium and barium ferrite powders were mechanically alloyed (MAed) using a vibrational ball mill.
Change in Vickers micro-hardness of the pure magnesium powders as a function of the mechanical milling (MM) times obeyed the crystallite size. Change in Vickers micro-hardness of the composite powders as a function of the amount of barium ferrite obeyed the rule of mixture when the MA time was 120 and 240 min.. On the other hands, change in Vickers micro-hardness of the composite powders as a function of the amount of barium ferrite wasn't obeyed the rule of mixture when the MA time was 20 and 60 min.. Magnetization of the composite powders obeyed the amount of the barium ferrite powder, whereas coercive force of the MAed powders decreased due to the refinement of the barium ferrite powder.
Mg-based composite powders with high hardness and hard magnetic properties were successfully produced by mechanical alloying.抄録全体を表示PDF形式でダウンロード (1099K)
本会記事
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2011 年 58 巻 4 号 p. Pref4_1
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスPDF形式でダウンロード (69K) -
2011 年 58 巻 4 号 p. MtgPr4_1-MtgPr4_21
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスPDF形式でダウンロード (644K)
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2011 年 58 巻 4 号 p. 243-258
発行日: 2011年
公開日: 2011/06/29
ジャーナル オープンアクセスPDF形式でダウンロード (2900K)
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