著者

黒木 英憲 徳永 洋一

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.20, no.2, pp.49-54, 1973-06-25 (Released:2009-05-22)

参考文献数

10

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Impact strength of iron compacts, prepared from commercial powders by single compacting under the pressure of 2-9 t/cm2 and by sintering in hydrogen at the temperature range of 1100-1300°C for less than 1 hr, did not simply increase with densification at room temperature, but decreased in the density range around 7 g/cm3.Three different mechanisms for the observed phenomena of abnormal brittleness were considered.First, a shear crack could propagate through large flaky pores formed by the removal of pressed powder lubricants between iron particles. This type of brittleness disappeared after the elimination of flaky pores by sintering at higher temperatures for longer periods.Second, an abnormal growth of ferritic grains could cause an increase of ductile-brittle transition temperature, together with the increase of porosity on grain boundary. This type of brittleness was the same as previously observed by the authors on double pressed materials, and it became remarkable with the progress of sintering.Third, when the ductile-brittle transition occurred above room temperature, the impact strength of high density (above 7 g/cm3) sintered irons could become lower than that of lower density ones at room temperature, because the transition appeared more evidently with densification.

著者

Muhammad KOZIN Keisuke KUSAKABE Masatoshi ARAMAKI Naoya YAMADA Satoshi OUE Yukiko OZAKI Osamu FURUKIMI Masaki TANAKA

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.67, no.4, pp.173-181, 2020-04-15 (Released:2020-04-15)

参考文献数

24

被引用文献数

1

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In the present study, we have examined the wear properties of the sintered pure iron subjected to two distinct heat treatments such as nitriding-quenching (NQ) and carburizing-quenching (CQ). Based on our current observations, the martensite layer was formed on the surface layer following each treatment, whereas the hardness of the NQ martensite was much higher than that of the CQ one. The wear of the CQ specimen was slightly smaller than that of the NQ martensite, despite the lower value of the initial hardness. Meanwhile, the hardness of the CQ surface after the sliding tests significantly elevated relative to the NQ surface resulting in the better wear resistance. EBSD analysis demonstrated that the plastic deformation on the CQ surface along the sliding direction. Furthermore, the micro area X-ray diffraction along the surface layer of the CQ surface showed that a small amount of the retained austeite which reduced locally during the test. Therefore, the CQ-treated surface showed the excellent wear resistivity due to the surface hardening by the stress-induced transformation of the retained austenite dispersed in the martensite, in addition to the strain hardening of the martensite itself. In contrast, the worn surface of the NQ specimen showed slight plastic deformations of the ferrite grains beneath the martensite layer, but not in the surface martensite layer. This deformation under the martensite layer was due to the hardness gap between inward and the heat-treated surface, and might contribute to form the concave profile on the sliding surface. Consequently, this study could demonstrate such the difference in the wear mechanisms between the CQ and the NQ specimens.

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

---

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

高田 利夫

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.4, no.4, pp.160-168, 1958-04-05 (Released:2009-05-22)

参考文献数

8

被引用文献数

11 21

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Ferric oxide powders prepared by calcining iron salts exhibit a variety of colours, i. e. pure red, yellowish red, dark red, and black, according to the condition of calcination. Morphological studies revealed that the colour of powders is dependent upon the size and shape of the unit particles and their aggregates. The powders change in colour from yellowish red or dark red to black as the size of unit particles or of their aggregates increases. On the basis of this result explanations were given to the nature of colour of glaze containing iron red and, also, of water containing Fe2O3 in colloidal subdivision.

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

---

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

井川 良雄 熊谷 憲

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.38, no.4, pp.552-556, 1991

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The Osprey Process introduced here is a kind of spray deposition, available for manufacturing bulk preform of high density and high strength by one process straight from molten metals.<BR>The characteristics of this osprey preform are as follows;<BR>(1) Osprey preform density as deposit is higher than 99.4% for high speed steel (Disc preform) and higher than 99.3% for high carbon high speed steel (Tube preform).<BR>(2) The transverse rupture strength of Osprey preform after forged is superior to that of wrought alloy.<BR>(3) The transverse rupture strength of Osprey preform after HIP treatment is 2 times as high as that of conventional cast.<BR>(4) The density and strength of Osprey preform which were adequately deposited, worked and heat treated are expected to be improved further.

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

---

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

加藤 和夫 森川 満隆 田上 道弘 山田 眞二 武田 徹

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.50, no.12, pp.1057-1061, 2003-12-15

参考文献数

5

---

In the previous paper, we reported the densification of the bronze matrix was promoted by the diffusion of Cr under solid state sintering at 1030 K. In the present work, effects of V addition on sintering properties and microstructures of the bronze matrix were investigated, and compared with Cr. Mixed powders were prepared from pulverized V powders and atomized 90Cu-10Sn powders, of which particle sizes were 106-150μm and 1-38μm respectively. Compacts pressed at 390 MPa were sintered at 670-1030 K for 0.3-180 ks in H2. V diffuses preferentially into the surface and grain boundary of the bronze powder. With increasing sintering time at 1030 K, pores of matrix decrease rapidly. This indicates that the densification of the bronze is promoted by the diffusion of V as same as the case of Cr. However, some pores are observed on the matrix and the grain size is bigger than the case of Cr after 180ks sintering at 1030 K. From these results, it is assumed the effects of densification by V addition is slightly smaller than Cr.

著者

加藤 和夫 田上 道弘 山田 眞二 武田 徹

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.49, no.9, pp.812-817, 2002-09-15

参考文献数

8

被引用文献数

1 1

---

In order to develop Graphite dispersed sintered bronze bearing material standing in the use of a higher load application, effects of Cr addition on sintering properties and microstructures of the bronze matrix were investigated. Mixed powders were prepared from elemental Cr powders and atomized 90Cu-10Sn powders, of which particle sizes were 106-50μm and 1-38μm, respectively. Compacts pressed at 390 MPa were sintered at 670-1030 K for 0.3-180 ks in H<SUB>2</SUB>. With increasing sintering time at 1030 K, pores decrease rapidly with the refinement of grain size in the bronze matrix surrounding Cr particle. This indicates that the densification of the bronze is promoted by the diffusion of Cr.

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

木村 朝 鈴木 福二

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.34, no.9, pp.497-501, 1987-11-25 (Released:2009-05-22)

参考文献数

3

被引用文献数

6 7

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Colored nacreous pigment used so far is a mixture of various colored pigments and titanium dioxide coated mica (TiO2-coated mica). One of the major problems for apprications to cosmetics and other fields is the lack of stability and safety of it. We have developed a colored nacreous pigment having bright color tone and pearly gloss having excellent stability and safety. In order to obtain such colored nacreous pigment, a part of titanium dioxide layer on mica was reduced to black titanium oxide, and then the reduced TiO2-coated mica was coated with titanium dioxide. The products obtained were the colored nacreous pigment, which was colored by interference color of titanium dioxide, and had extremely improved color tone, good consistency of color appearance and interference color. Various colors were available by adjusting the thickness of the titanium dioxide layer coated on the reduced TiO2-coated mica. This colored nacreous pigment does not contain any colored pigments.

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

渡邊 〓尚

出版者

Japan Society of Powder and Powder Metallurgy

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.48, no.9, pp.769-776, 2001-09-15 (Released:2010-07-12)

参考文献数

37

被引用文献数

1 3

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Porous sintered bearings are of a metal structure containing a multitude of pores that are connected with each other and also with the surface. The pore volume incorporated in the bearings varies from about 10 to 40 vol%. This pore volume serves as strage for a fluid lubricant with which the part has been impregnated during its manufacture. In most applications, the lubrication is produced within the bearing itself.This report is containing an outline of sintered porous bearings and introductions of writer's researches on the bearings and then, some suggestions on the progress of the bearings, in conformity with the writer's research life for about fifty long years.

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

---

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.