著者

菅野 了次

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

pp.23-00044, (Released:2023-12-05)

参考文献数

106

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We have been conducting research to explore new materials and their use in batteries by pursuing the phenomenon of high ion diffusion in solids. Lithium ion conducting materials have been particularly explored because of their potential application to all-solid-state batteries with high energy density. In addition to an overview of lithium ionic conductors, we will review the material search process for Li10GeP2S12, which exhibits particularly high ionic conductivity. We will also review the research that clarified the formation region of this material, investigated the ionic conduction mechanism, and applied this material to all-solid-state batteries.

著者

石神 健太 橋詰 良樹 村上 勇夫 木村 貴広 中本 貴之

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.68, no.4, pp.129-132, 2021-04-15 (Released:2021-04-15)

参考文献数

8

被引用文献数

1

著者

合田 義弘

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.69, no.Supplement, pp.S109-S117, 2022-01-30 (Released:2022-01-30)

参考文献数

74

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Development of high-performance permanent magnets relies on both the main-phase compound with superior intrinsic magnetic properties and the microstructure effect for the prevention of magnetization reversal. In this article, the microstructure effect is discussed by focusing on the interface between the main phase and an intergranular phase and on the intergranular phase itself. First, surfaces of main-phase grains are considered, where a general trend in the surface termination and its origin are discussed. Next, microstructure interfaces in SmFe12-based magnets are discussed, where magnetic decoupling between SmFe12 grains is found for the SmCu subphase. Finally, general insights into finite-temperature magnetism are discussed with emphasis on the feedback effect from magnetism-dependent phonons on magnetism, which is followed by explanations on atomic arrangements and magnetism of intergranular phases in Nd-Fe-B magnets. Both amorphous and candidate crystalline structures of Nd-Fe alloys are considered. The addition of Cu and Ga to Nd-Fe alloys is demonstrated to be effective in decreasing the Curie temperature of the intergranular phase.

著者

宗藤 伸治 刑部 有紀 山外 啓太 岩永 純平 三浦 秀士 古君 修

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.64, no.8, pp.471-474, 2017-08-15 (Released:2017-08-31)

参考文献数

9

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Poly-crystalline Ba8AuxSi46−x clathrate with p-n junction was synthesized for electric power generation from heat under no temperature difference. The n-type Ba8Au4.5Si41.5 and the p-type Ba8Au5.5Si40.5 powder were stacked in the graphite die and sintered by a Spark Plasma Sintering (SPS) method at 1073 K for 5 min with pressure of 50 MPa. The Au composition of Ba8Au4.5Si41.5 and Ba8Au5.5Si40.5 side in the sintered sample were Ba7.8Au4.2Si41.8 and Ba7.8Au5.2Si40.8, respectively. It was found that the Au composition was gradually changed near the interface with thickness of around 500 micrometers. Electric power generation test under no temperature difference was performed by using the sample cut to contain the interface of two layers. The electric power increased by only heating and the maximum voltage can be observed around 2 mV at 773 K. These results suggested that electron excitation occurred near the n/p interface and generated electrons and holes diffuse to n-type and p-type semiconductor side, respectively.

著者

藤 正督 ラザヴィ ホソロシャヒ ハディ 高井 千加 佐藤 知広 尾畑 成造 立石 賢司

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.65, no.10, pp.609-615, 2018-10-15 (Released:2018-11-08)

参考文献数

12

被引用文献数

2 2

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Sintering of most ceramic and composite materials are only possible at temperatures over 1000°C due to their high melting point. Sintering is acknowledged as an expensive process, which takes several hours to several days. In addition, high temperature sintering affects the final product by causing undesired grain coarsening or changing the initial chemical stoichiometry. Our research group has proposed a “non-firing sintering”, where no firing process is required for achieving high densities. The underlying idea of this method involves the chemical activation of powder surface via ball milling, where the surface of particles is rubbed against balls. In this review, we will introduce the mechanism of the method as well as some process know-how, with some examples of preparing solidified bodies of silicon carbide, composite of carbon nanotube (CNT) and silica, and organic/inorganic composite materials.

著者

李 素妍 松井 敏也 奥山 誠義 吉川 英樹 伊勢 孝太郎 稲田 健一

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.63, no.8, pp.725-730, 2016-07-15 (Released:2016-07-29)

参考文献数

13

被引用文献数

1 1

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The purpose of this study was to identify the morphological characteristics and chemical properties of pipe-shaped iron oxide particles depending on the manufacturing method and provide information on possible manufacturing methods and locality survey of the excavated iron oxides. We collected samples around the Toratsuka Tomb and performed firing, followed by optical microscopy, scanning electron microscopy, X-ray fluorescence analyses, and X-ray diffraction analyses. Based on the results, it was demonstrated that the annealing temperature has no effect on the shape of the iron oxide samples while the particle size as well as the color and intensity ratio of iron oxide differed with the annealing temperature. We also obtained information on minor constituents of the iron oxide samples through elemental analyses and gained knowledge on determining the locality by identifying the contained elements.

著者

深津 保

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.4, no.2, pp.74-87, 1956-10-24 (Released:2009-05-22)

参考文献数

52

被引用文献数

1

著者

小原 学 西村 拓家 濱田 泰嗣

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.62, no.7, pp.349-354, 2015-07-15 (Released:2015-07-28)

参考文献数

11

被引用文献数

1 2

---

In this research, it was carried out to investigate the effect of Zn substitution on magnetic properties and crystal structures of Ca-La-Co-Zn system ferrite sintered magnets. The results show that M type single phase was obtained from 0–0.2 of Zn substitution in (Ca0.5La0.5)1.1Co0.4-xZnxFe11.6O19 sintered magnets. Magnetization of sintered magnets with same densities increase with an increase the value of Zn substitutions. Coercivity of sintered magnets with same average particle size decrease with an increase the value of Zn substitutions.

著者

梅田 純子 三本 嵩哲 今井 久志 近藤 勝義

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金

巻号頁・発行日

vol.64, no.2, pp.81-87, 2017

---

訂正<BR><BR><p>本誌,第63巻第12号(2016)1002-1008頁に掲載された論文は,著者修正前の原稿で誤って掲載されました.著者より修正の申し出がありました.修正後の論文をここに改めて全文掲載します.</p>

著者

亀井 利久 荻野 哲

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.65, no.6, pp.307-310, 2018-06-15 (Released:2018-06-28)

参考文献数

16

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As a new broadband-wave absorber material in millimeter waves, the thin rubber sheet containing a porous carbon material “PHYTOPOROUS” made from plant-based ingredients were prepared. We investigated the complex permittivity εr*and the reflection loss Γ measured by free-space method using dielectric lenses and incident angle dependence of the reflection loss measured by free-space arch method. The rubber sheet containing PHYTOPOROUS made from soybean hulls showed the reflection loss of more than −20 dB with a bandwidth of 18 GHz at centered frequency of 90 GHz.

著者

三宅 隆 原嶋 庸介 深澤 太郎 赤井 久純

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.69, no.Supplement, pp.S99-S108, 2022-01-30 (Released:2022-01-30)

参考文献数

103

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First-principles calculation based on density functional theory is a powerful tool for understanding and designing magnetic materials. It enables us to quantitatively describe magnetic properties and structural stability, although further methodological developments for the treatment of strongly-correlated 4f electrons and finite-temperature magnetism are needed. Here, we review recent developments of computational schemes for rare-earth magnet compounds, and summarize our theoretical studies on Nd2Fe14B and RFe12-type compounds. Effects of chemical substitution and interstitial dopants are clarified. We also discuss how data-driven approaches are used for studying multinary systems. Chemical composition can be optimized with fewer trials by the Bayesian optimization. We also present a data-assimilation method for predicting finite-temperature magnetization in wide composition space by integrating computational and experimental data.

著者

神田 康行

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.70, no.3, pp.145-152, 2023-03-15 (Released:2023-03-15)

参考文献数

33

被引用文献数

1

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This report investigated the spark plasma sintering (SPS) of Shuri castle breakage roof tile powder for the effective utilization of the Shuri castle breakage roof tiles. First, we examined the fundamental characteristics of Shuri castle breakage roof tiles. The chemical composition of broken roof tiles mainly comprises SiO2. Scanning electron microscopy analysis revealed the dispersion of quartz lumps in the inner structure. Additionally, the density of the broken roof tile was 2.43 g/cm3, and the open porosity was 17.9%, the Vickers hardness (HV) was 87.5 at the matrix side and 1200 at the quartz lump, and the flexural strength was 15.7 MPa. Meanwhile, the fundamental characteristics of the SPS compact formed using breakage roof tile powder comprised a density of 2.68 g/cm3, an open porosity of approximately 0%, an HV of 259, a flexural strength of 105 MPa, and a flexural modulus of 83.1 GPa at a sintering temperature of 1323 K. The formation of magnetite was confirmed via X-ray diffraction patterns of the sintered products; however, the crystalline phases were almost identical to those of the broken roof tile powders.

著者

吉田 周平 池内 琢人 BHATTACHARJEE Tilak BAI Yu 柴田 曉伸 辻 伸泰

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.67, no.3, pp.113-120, 2020-03-15 (Released:2020-03-15)

参考文献数

63

被引用文献数

1

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High entropy alloys (HEAs) and medium entropy alloys (MEAs) are new classes of materials, defined as alloys composed of five or more and four or fewer kinds, respectively, of alloying elements with (near-)equiatomic concentrations. In the present article, we reviewed our recent works on ultra-grain refinement of HEAs and MEAs. CoCrFeMnNi HEA and its sub-system MEAs were highly deformed by high-pressure torsion and subsequently annealed under various conditions to obtain fully-recrystallized microstructures with FCC single phase having different mean grain sizes. It was found that ultrafine-grained (UFG) microstructures could be easily obtained by simple thermomechanical processes. Grain size and chemical composition dependence on mechanical properties of the HEA and MEAs were evaluated by tensile tests at room temperature. UFG HEAs and MEAs exhibited characteristic phenomena, such as discontinuous yielding and extra-hardening, similar to other UFG metals. In addition, the UFG HEAs and MEAs showed better strength-ductility balance compared with conventional UFG metals. Friction stresses of HEAs and MEAs were determined from Hall-Petch relationships and found to be much higher than those of pure metals and dilute alloys having FCC structure. Analysis based on theoretical models suggested that the high friction stress reflected atomic-scale heterogeneity in HEAs and MEAs.

著者

牧 涼介 彭 沢亮 福原 実 草野 圭弘

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.69, no.10, pp.409-414, 2022-10-15 (Released:2022-10-15)

参考文献数

11

被引用文献数

1

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Bizen stoneware is produced by firing shaped green clay in a firewood kiln at around 1200°C. The brownish and blackish colors that appear on the stoneware surface in a firewood kiln do not appear on stoneware heated in an electric furnace. The brownish color was found to be caused by the formation of single crystalline, branched, dendritic, Al-substituted ε-Fe2O3 particles. Composite particles consisting of Al-substituted ε-Fe2O3 and Fe-substituted spinel solid solution also formed on the stoneware surface. In this study, we successfully prepared brownish samples that were similar in color to Bizen stoneware by annealing at 1200°C for 2 h in air after heating Bizen clay pellets with K2CO3 at 1230°C under a 10 vol% CO and 90 vol% Ar gas mixture in an electric furnace instead of firing in a firewood kiln. Dendritic hematite particles also formed on the reproduced samples. The blackish color on Bizen stoneware fired in a firewood kiln was caused by the formation of augite [(Ca,Mg,Fe)2Si2O6], which was produced by a reaction between the Bizen clay and firewood ash.

著者

宮内 創 横田 耕三

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.67, no.8, pp.441-446, 2020-08-15 (Released:2020-08-15)

参考文献数

14

被引用文献数

1

---

This research evaluated the effect of nitrogen absorption into austenitic stainless steel in selective laser melting (SLM) process. Microstructures and mechanical properties of SUS316 specimens fabricated by SLM in different atmosphere, nitrogen and argon, were investigated. The results of microscopy observation of as-built specimen fabricated in nitrogen showed a fine cellular microstructure. In contrast, coarse columnar grains grew up from melt pool boundaries were observed in the microstructure of as-built specimen fabricated in argon. The ultimate tensile strength, yield strength and hardness of as-built specimen in nitrogen were considerably higher than those of specimen in argon and conventionally processed material. These were considered to be the cause of the difference in microstructures and nitrogen absorption. Post-SLM solution heat treatment (SHT) reduced the tensile strength and hardness of both specimens and improved their ductility. However, the tensile strength and hardness of the specimen in nitrogen were still higher than those in argon.

著者

榎本 兵治

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.66, no.11, pp.513-524, 2019-11-15 (Released:2019-11-15)

参考文献数

22

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This paper describes characteristic profiles of explosibility and ignitability of metal powders as well as their possible hazards, in most cases, in comparison to those of organic dusts. Metals are mostly pure materials and their physical and thermochemical properties are well known, so that it was tried to explain their performances on the basis of their properties, which may help the estimation of explosibility and ignitability of metal powders that are not yet known.

著者

細川 三郎 松本 祥吾 多田 稜平 芝野 卓也 田中 庸裕

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.64, no.11, pp.583-588, 2017-11-15 (Released:2017-11-29)

参考文献数

29

被引用文献数

1 2

---

Mn-modified hexagonal YbFeO3 (Mn-YFO) synthesized by a solvothemal method is found to have a higher catalytic activity for C3H8 or CO oxidation than noble metal catalyst, Pd/Al2O3. The catalytic activity is mainly due to amorphous MnOx species located on ab plane of the hexagonal lattice. A small amount of Pd loading on Mn-YFO drastically enhances the catalytic activity; that is, 0.5 wt% Pd/Mn-YFO shows excellent activity for CO oxidation that exceeds the activity of 2.0 wt% Pd/Al2O3. The Pd loading dramatically improves the reducibility of the MnOx species and also CO adsorption to Mn-YFO. Thus, we demonstrate that an extremely small amount of Pd species plays a role as a promoter for the catalytic and reduction functions of the MnOx species on Mn-YFO. It is expected that the establishment of such promoter effect will provide a novel guideline for reducing the use of precious metal resources.

著者

鄂 剛 吉川 信一 金丸 文一 田中 功

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.38, no.2, pp.215-218, 1991

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High pressure synthesis was performed on 123 and 124 phases in Y-Ba-Cu-O system under a pressure of 3GPa at 950&deg;C. Lattice parameters and superconducting properties changed with an annealing duration under pressure in 123 phase with oxygen content X=7. The 123 product obtained from raw materials with X=8.5 had a tetragonal lattice with a=c/3=3.87A. Its real oxygen content could be estimated to be 7.3 from the lattice parameter, Raman spectroscopy, and also Rietveld analysis. The product seemed to be semiconductor containing a small amount of superconductor. 124 phase was obtained by a reaction at 950&deg;C with its successive annealing at 700&deg;C under 3GPa adjusting oxygen content of raw material to the exact composition of the product.

著者

宮城 加津也 深野 陽介

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.68, no.10, pp.409-414, 2021

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<p>Verification of the manufacturing conditions for translucency ceramics are showed using powder forming and sintering method in order to establish the manufacturing technology for optical devices with arbitrary complex shape and shape retention, and high-optical excitation. However, this method is extremely difficult to obtain translucency ceramics because the combination of complex factors such as "the shape and particle size of the raw materials, forming conditions and sintering" adversely affect the translucency of the sintered material, which is caused by the transmitted light scattering of the sintered material. Therefore, we have succeeded in realizing translucent ceramics by examining these complicated factors (materials, molding, sintering conditions, crystallization) and specifying the amorphous sintering conditions and the densification-molding conditions necessary to eliminate the light scattering factors inherent in sintered materials. It is necessary to show the correlation of the volume change with respect to T_g-temperature and T_m-temperature, which are important regarding amorphization, considering the sintering treatment conditions that depend on the particle size of the raw material fine powder, and to specify the molding body-pressurization (pressure and time) conditions. These optimizations will make it possible to develop the expected high-functional-photoelectric optical devices with microstructures and, high-power laser light sources independent of materials.</p>

著者

佐藤 克明 坂 勉 酒井 純 高木 善昭

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.43, no.11, pp.1328-1332, 1996-11-15

参考文献数

1

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The pulleys are used to be produced by powder metal due to cost performance and high productivity. Recently, the timing belt pulleys for automotive engine are required extra high functions which have sensor or light weight, and the complex shape pulleys are tend to increase. This report introduces the examples of the design and engineering of these pulleys as follows.<BR>1)The light weight pulleys with thin wall curtain shape rim are lighter than stamping pulleys.<BR>2)The cam shaft pulleys with sensing cam are manufactured as utilizing powder flow during compacting.<BR>3)The crank shaft pulleys with sensing cam at flange portion for miss fire detection have high accuracy of angle phase between key way and sensing cam.