巻号一覧
58 巻, 2 号
February
選択された号の論文の13件中1～13を表示しています
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研究
研究
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尾崎 由紀子, 尾野 友重, 高宮 嗣幸, 上ノ薗 聡2011 年 58 巻 2 号 p. 83-90
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスApparent density (AD) has a close correlation with green density of a compacted body because AD is one of important scales indicating the filling structure of powder particles in a die. In this study, to clarify the effect of AD on green density, an annealed atomized iron powder of quite high AD (3.95 Mg/m3) was prepared, and its compacting behavior was investigated by comparing a low AD (3.05 Mg/m3) powder. The high AD powder was made by sieving commercial atomized powder into 5 sizes, and blending them to provide the particle size distribution of the lowest porosity, which was simulated by the calculation using "Multi-component randomly packed bed model". The green densities of the high AD powder compacted at 686 MPa/130°C was 7.55 Mg/m3, which was higher than that of the low AD powder.
The compacting processes were analyzed in accordance with Cooper-Eaton type formula. The analysis showed that particles deformation started at lower pressure in the low AD powder in comparison with the high AD powder. Micro-Vickers hardness of particles in the compacted green of the low AD powder was wholly higher than that of the high AD powder. Because, in the low AD powder, the powder particles could be packed roughly and inhomogeneously in a die, and compacting stress should concentrate in locally densed area, work hardening of particles could start at lower applied pressure and progress more. In compacting process, work hardened particles should suppress particle deformation, resulting in the lower green density. This result makes it clear that the increase in AD is effective on uniform and dense powder packing in a die, which results in high green density by delaying the start of work hardening.抄録全体を表示PDF形式でダウンロード (823K)
研究速報
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Apiluck Eiad-ua, Takashi Shirai, Hideo Watanabe, Masayoshi Fuji, Koji ...2011 年 58 巻 2 号 p. 91-96
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスThe influence of the mechano-chemical activation on the fabrication of porous ceramics from black paper sludge ash (BPSA, waste materials) was studied using planetary ball mill to obtain activated powder. Mechano-chemical process is used to modify properties of materials, enhance the reactivity of materials and produce advanced materials. After mixing activated powder with alkaline solution (KOH) and kept until completely solidification in steam oven, so that porous ceramics were formed by generation of gas. The physical properties of the porous ceramics were investigated using SEM, X-ray CT and mercury porosimeter. Based on the results, mean particle size and the visible pore size of solidified specimen were decreased with increasing of rotation speed and treatment time. The porous structure can be controlled by generation of gas. These were used to explain the formation of the graded porosity.抄録全体を表示PDF形式でダウンロード (1061K)
特集：粉末冶金プロセスの制御と製品の特性評価
総報
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伊藤 孝至2011 年 58 巻 2 号 p. 98
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスPDF形式でダウンロード (151K)
研究
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勝山 茂, 前澤 文宏, 田中 敏宏2011 年 58 巻 2 号 p. 99-104
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスThe mixture of half-Heusler ZrNiSn crystal and ZrNi amorphous particles was sintered by Spark Plasma Sintering (SPS) method. The sintered body was composed of ZrNiSn crystal and ZrNi amorphous phases. The absolute values of the Seebeck coefficient of the ZrNiSn-ZrNi composite were more decreased than those of the sintered ZrNiSn crystal, but there was almost no difference in the electrical resistivity. Thermal conductivity was also more decreased in the ZrNiSn-ZrNi composite, which was mainly attributed to the decrease in the lattice component of the thermal conductivity. The complex formation of crystal and amorphous phases was efficient for the reduction of the thermal conductivity of the thermoelectric materials. The dimensionless figure of merit was increased in about 10 % in the composite, but a considerable improvement was not produced by the complex formation.抄録全体を表示PDF形式でダウンロード (765K) -
佐々木 光, 藤間 卓也, 高木 研一2011 年 58 巻 2 号 p. 105-109
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスBoron-rich thermoelectric materials have been reported to have a large Seebeck coefficient and low heat conductivity and are advantageous for its power generation efficiency. However, achieving high electrical conductivity is necessary for boron-rich thermoelectric materials to be used practically in wide range of application. The materials with high thermoelectric performance are produced by pressure sintering methods like Spark Plasma Sintering (SPS). Therefore, low productivity is another issue to overcome.
We investigated microstructure and thermoelectric performance of MgAlB14-base sintered bodies prepared by SPS and atmosphere sintering. The samples contain a by-product, MgAl2O4, and a material prepared by atmosphere sintering exhibited a high Seebeck coefficient more than 350 μV/K at 400-600°C, that indicated the atmosphere sintering can produce MgAlB14-base thermoelectric materials of a high Seebeck coefficient with higher productivity.抄録全体を表示PDF形式でダウンロード (862K) -
山田 高広, 苅谷 英里, 森戸 春彦, 高橋 純一, 山根 久典2011 年 58 巻 2 号 p. 110-115
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスPolycrystalline bulk β-FeSi2 samples were prepared by heating a compact body of Fe powder in a Na-Si melt at various conditions, such as density of the Fe compact and the ratio of the source materials. Single-phase bulk β-FeSi2 samples were prepared by heating Fe compact with density below 3.9 g cm-3, Si powder with a Si/Fe molar ratio above 2.25, and Na with a Na/Si molar ratio above 0.33 at 800°C for 12 h. Fe powder reacts with Si dissolved in the Na-Si melt and forms ε-FeSi, followed by changing to β-FeSi2 due to the diffusion of Si while the Na-Si melt soaks into the compact via voids in the compact. Cobalt (Co)-doped β-FeSi2 bulk samples were prepared by heating compact bodies of powder mixtures of Fe powder with grain size of < 45 μm and Co powder with grain sizes of 1-2 μm or < 150 μm in a Na-Si melt. The Co-doped bulk sample prepared with Co powder of 1-2 μm grain size was homogeneous and showed thermoelectric properties better than those of the sample prepared with Co powder of < 150 μm in grain size. It is considered that Co-doped β-FeSi2 is formed by mutual diffusion between β-FeSi2 and Co silicides.抄録全体を表示PDF形式でダウンロード (1459K) -
佐藤 裕人, 山田 高広, 森戸 春彦, 山根 久典2011 年 58 巻 2 号 p. 116-120
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスNbSi2 powder was prepared by heating a mixture of Nb and Si powders with a molar ratio Nb:Si:Na=1:2:x (x=0.067-2.0) at 900-1100 K for 1-48 h under an Ar atmosphere. The powder sample prepared at x=2.0 and 1000 K for 12 h was single-phase of NbSi2. The grain size of NbSi2 powder (1-20 μm) was smaller than Nb powder (< 75 μm). The crystallinity and formation rate of NbSi2 were improved by increasing temperature. O and Na contents in the sample which was washed with CH3COOH and distilled water were 0.36 wt% and < 0.05 wt%, respectively.抄録全体を表示PDF形式でダウンロード (849K)
技術速報
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Francis Hanejko, Peter Sokolowski, Kalathur Narasimhan, Tony Nishida2011 年 58 巻 2 号 p. 121-124
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスSponge iron powder has been an important product for the powder metal industry globally. However increasing material prices and advancements in water atomized powder made sponge iron powder less attractive in some parts of the world. However sponge iron powder has some unique benefits. Advancements in atomizing technology allowed us to develop a sponge like iron powder by water atomized powder. We report the benefits of this new atomized sponge iron powder. The goal of this program was to provide a cost effective atomized powder with high green strength and similar apparent density to existing sponge iron grades.抄録全体を表示PDF形式でダウンロード (955K)
研究速報
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中谷 和通2011 年 58 巻 2 号 p. 125-127
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスThe effect of the history of powder movement on filling density was investigated with pre-mixed powder with a composition of Fe-2mass%Cu-0.9mass%C-0.8mass%Lubricant. The number of shaking and elapsed time after shaking were used as substitutes for the history of the powder movement. From these experiments it is clarified that filling density was greatly effected by the history of powder movement just before filling. The more shaking just before the filling made the filling density lower, and the longer elapsed time after shaking made the filling density higher. However, filling density of 100mass%-Fe powder was not effected by the history of movement.抄録全体を表示PDF形式でダウンロード (505K)
研究
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三宅 賢武, 松本 伸彦, 近藤 幹夫2011 年 58 巻 2 号 p. 128-133
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスIn this study, iron-lubricant mixed powders were made with the dry mixing device to give mechanical energy and plasma (NC method) and ball mill (BM method), and the effects of mixing method on adhesion state of lubricant, powder characteristics, ejection force, green density and green strength were investigated. As the result, in the NC method, the lubricant evenly bonded the surface of iron powder, and it was effective for lowering of ejection force and improvement of green density. In the BM method, the lubricant bonded on the craters of iron powder, and it was effective for improvement of powder characteristics and green density.抄録全体を表示PDF形式でダウンロード (1412K) -
福田 泰隆, 林 偉平, 小倉 邦明2011 年 58 巻 2 号 p. 134-138
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスIron hollow spheres were fabricated by reduction sintering process. The reduction of iron oxide completed in a range from 573 to 973 K, and the shrinkage (sintering) advanced rapidly in a range from 673 to 1073 K. In spite of the large shrinkage, the shape of sintered body showed only an at all small distortion from a sphere. The compression curve of the block which joined iron spheres showed the plateau load region where a load change is small, and the average plateau load strongly depends on the compression strength of unit spheres. By means of chemical reaction controlled un-reacted core model, activation energy of reduction process has been estimated to be 22 kJ/mol.抄録全体を表示PDF形式でダウンロード (1262K)
新技術・新製品
新技術・新製品
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高橋 真司, 久行 優梨恵, 河端 優, 蔵田 克彰, 伊藤 幸一2011 年 58 巻 2 号 p. 141-143
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスPDF形式でダウンロード (905K)
本会記事
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2011 年 58 巻 2 号 p. Pref2_1
発行日: 2011年
公開日: 2011/05/20
ジャーナル オープンアクセスPDF形式でダウンロード (89K)
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