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

---

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

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

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

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

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

---

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

鈴木 建次 三谷 裕康

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.26, no.6, pp.228-231, 1979-08-25 (Released:2009-12-04)

参考文献数

3

被引用文献数

1 1

---

By using an acoustic method, the duration of reverberation of γ′-Ni·Al bronze sintered alloy was compared with those of Cu-10wt%Sn, Fe-10wt%Cu and α-Ni·Al bronze sintered alloys. The relationship between the duration of reverberation and internal friction was discussed. It was found that the duration of reverberation in this γ′-Ni·Al bronze sintered alloy is extremely shorter than those in other alloys, and decreases linearly with increasing internal friction.

著者

鰐川 周治 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.39, no.12, pp.1145-1150, 1992

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By using the planetary, screw disc and vibration type ball mills, mechanically activated states of Ti-C powders formed in milling were investigated with the change of their reaction temperature. The temperature decreased with increasing milling time, and its relation is characteristic of the milling methods. Especially, in case of the vibration mill, there is clear indication that the reaction temperature of milled powder was saturated at a constant value as the lapse of the milling time, and also the size of balls charged in mill influenced markedly to the reaction temperature.

著者

河野 富夫 洞田 亮 近藤 鉄也

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.44, no.11, pp.985-992, 1997-11-15 (Released:2009-05-22)

参考文献数

27

被引用文献数

14 18

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The properties of typical pure Ti and Ti-6Al-4V alloys produced by Metal Injection Molding (MIM) process have been investigated in detail after optimization of the powder characteristic, debinding and sintering conditions for the process.(1) Sintered pure Ti using the blended in equal amount of hydrided-dehydrided and gas-atomized powders has better tensile strength (640MPa) and elongation (21%), which properties are similar to the JIS 3 grade of wrought pure Ti.(2) Sintered Ti-6Al-4V alloys produced by both mixed elemental and prealloyed powders have good tensile strength (970MPa) and elongation (12%), which are almost comparable to those of wrought Ti-6Al-4V alloys.(3) Polishability of sintered pure Ti is generally poor. However, the specific heat treatment leads to fairly improved polishability because of the grain refining which is also favorable for the mechanical properties.

著者

石橋 渡

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.24, no.4, pp.107-112, 1977-06-05 (Released:2009-05-22)

参考文献数

8

被引用文献数

3 4

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As an application of electrode erosion by electric discharge, a new method was developed in which fine powder was produced by the spark discharge.When metal pellets are dipped into the liquid medium, the contact points of each pellets form the spark points. The pellets repel momentarilly each other by the impulse of spark discharge, and maintain its steady spark discharge by shifting the contact points and inhibiting the conversion to arc discharge. Thus fine powder is produced at spark points.In spark discharge circuit, electrostatic capacity of condenser is set as small as possible, and enhances the condenser energy by higher charge voltage. In addition, the discharge voltage is brought to be higher by quenched spark gap.The powder quantity is increased with the higher discharge voltage (10-40 kV) and its particle size becomes smaller with increase of frequency (230-610 kHz). Discharge condition has been investigated for producing fine powder (0.05-5μm) from aluminum, copper and iron materials. Finally the theoretical description has been given with regard to the mechanism of producing the fine powder at spark points.

著者

原田 幸明 菅 広雄

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.33, no.2, pp.63-68, 1986-02-25 (Released:2009-05-22)

参考文献数

16

被引用文献数

1 1

---

Some of the processing parameters for centrifugal atomization of molten metal were studied by means of a model-experiment using water.The shape and revolution velocity of the high speed rotating stages affected the size and the scattering distribution of disintigrated droplets. In the atomization using a flat stage, liquid disintegrated into smaller particles but sticked considerably to the wall of the apparatus. Conical type stages lessened the sticking and increased the portion of the larger drops slightly. Higher velocity revolution made finer particles and narrowed the scattering range of drops at the bottom of the chamber closely to the center. The wettability of the liquid on the stage surface was found to be an important factor for the disintegration of the liquid. Enhanced wettability brought direct drop formation, while poor wettability brought ligament disintegration.

著者

安永 弼

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.8, no.6, pp.253-264, 1961-12-25 (Released:2009-05-22)

参考文献数

17

被引用文献数

4 3

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The crystals of ammonium paratungstate were thermally decomposed in both air and vacuum, and the process of thermal decomposition of this salt and the formation of tungsten trioxide particles were studied by means of following measurements, (i) weight (ii) determination of the evolved ammonia gas, (iii) the differential thermal analysis, (iv) the X-ray analysis, (v) the surface area measurement and also (vi) the observation by electron microscope.The result obtained are as follows;(1) The dehydration of the crystal takes place completely below 250°C. The evolution of ammonia occurs in several stages extending to 420°C.(2) The a-tungsten trioxide are obtained at the temperatures above 420°C by the decomposipion in air. The particle of a-tungsten trioxide consists of small unit particles which are linked with each other, forming an aggregate whose shape are resemble that of the mother salt.(3) When the salts are decomposed in vacuum, 7-tungsten oxide are obtained at the temperature ranging from 400-500°C, and 8-tungsten oxide at the temperature higher than 500°C. The shape of the particle thus obtained was somewhat different from that of a-tungsten obtained in air.Experimental results, and the considerations on the mechanism of decomospition and also the formation of tungsten trioxide are described in detail.

著者

平野 眞一 田島 伸

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.37, no.3, pp.421-425, 1990-04-25 (Released:2009-05-22)

参考文献数

12

被引用文献数

3 2

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The formation process and magnetic properties of Fe3C particles were investigated. Various iron oxides as a starting material were carbureted with CO gas in a furnace. Fe3C was formed at the reaction temperatures from 450 to 600°C. The partial pressure of CO gas was controlled by mixing with N2 gas to prevent the free carbon deposition due to the disproportionation of CO gas. Synthesized Fe3C particles were identified as a single phase by XRD and the weight change measurement. The saturation magnetization of Fe3C increased from 80 to 117 emu/g with the increase of the reaction temperature, while the coercive force decreased from 170 to 80 Oe with the increase of the reaction temperature.

著者

高岡 勝哉 村瀬 康 加藤 将樹 廣田 健

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.57, no.2, pp.112-117, 2010-02-15

被引用文献数

1 1

---

Synthesis of dense composite materials with the compositions of Al<SUB>2</SUB>O<SUB>3</SUB>/Mo<SUB>2</SUB>N=100/0∼40/60 vol% has been attempted directly from Al<SUB>2</SUB>O<SUB>3</SUB>/Mo mixed raw powder compacts using capsule-free N<SUB>2</SUB> hot isostatic pressing (HIP). During HIPing [1500°C/(16∼20-200MPa)/1h], solid/gas reaction between Mo and N<SUB>2</SUB> was introduced to form Mo<SUB>2</SUB>N. The most of sintered composites consisting of only Al<SUB>2</SUB>O<SUB>3</SUB> and Mo<SUB>2</SUB>N phases reached to a higher relative density than 98.0 % with closed pores nevertheless capsule-free HIPing. Dispersion of Mo<SUB>2</SUB>N particles just formed suppressed the grain growth of Al<SUB>2</SUB>O<SUB>3</SUB> during sintering. Mechanical properties, such as bending strength (<I>σ</I><SUB>b</SUB>), Vickers hardness (<I>H</I><SUB>V</SUB>), fracture toughness (<I>K</I><SUB>1C</SUB>), and other properties have been evaluated as a function of their compositions. The best mechanical values of <I>σ</I><SUB>b</SUB> (∼573 MPa), <I>H</I><SUB>V</SUB> (∼20.3 GPa) and <I>K</I><SUB>1C</SUB> (∼5.00 MPa·m<SUP>1/2</SUP>) were attained at the composition of Al<SUB>2</SUB>O<SUB>3</SUB>/Mo<SUB>2</SUB>N=90/10 vol%, due to a high density (98.6 %) and small grain size of Al<SUB>2</SUB>O<SUB>3</SUB> matrix (<I>G</I><SUB>s</SUB>∼4.70 <I>μ</I>m). Further addition of Mo<SUB>2</SUB>N reduced the sinterability of matrix grains, resulting in low densities of around 90 % at the 40/60 vol% composition.

著者

岡 英夫

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.42, no.4, pp.544-547, 1995-04-15 (Released:2009-05-22)

参考文献数

7

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The magnetic agar, which was previously reported by the author, has several problems such as low permeability and complicated manufacturing process. The purpose of this study is to report a simple manufacturing process of the magnetic agar, by selecting magnetic powder of high permeability. Measurements show the mixing limits of magnetic powder and powder agar.

著者

後藤 公美

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.36, no.6, pp.761-769, 1989-08-25 (Released:2009-12-04)

参考文献数

24

被引用文献数

2 3

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Small particles of ferromagnetic BaO⋅Fe2O3, SmCo5, SM2Co17 and Nd2Fe14B compounds were prepared by the circumspect powder metallurgical method, and behaviours of their magnetic domains were studied with the decrease of the particle size.The colloid-SEM method invented by the present author was effectively used to observe domains of small particles less than 10 μm in size. With the decrease of the particle size the number of domains in one particle decreases, and finally the single-domain state is found for each compound, as expected by the theories. The critical size for single-domain particles, which is defined by the upper limit of the particle size range where the single-domain state can exist, is successfully estimated for all the above compounds from the particle size distribution curve of many single-domain particles, and obtained values of the critical sizes of the compounds are compared with the theoretical ones.

著者

中村 龍哉 松井 裕樹 山田 義博 田渕 光春 小林 陽

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.57, no.11, pp.725-728, 2010-11-15

参考文献数

17

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Cathode using the olivine particles was subjected to an open-circuit voltage measurement under the relaxation condition of 24 h at each SOC and DOD states. The electrochemical reaction in the LiFePO<SUB>4</SUB> cathode was composed of a large plateau around 3.45 V with sloped regions nearby for both the fully charged and discharged states. It was found that the potential profile in the sloped regions exhibited a hysteresis. Furthermore, both sloped regions became narrower when the operating temperature was raised from 30 to 60°C. Furthermore, it was found that the apparent diffusion coefficient of Li<SUP>+</SUP> ions in the sloped regions was much smaller than that in the plateau region. These facts implied that the obtained profiles were not in an equilibrium state with a quasi-OCV profile than the real one, and that the potential relaxation in the sloped regions took an extremely long time.

著者

河波 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.39, no.12, pp.1060-1066, 1992

被引用文献数

2 2

---

Development of toughened zirconia parts for grinding was reviewed. This work was achieved by developing the high purity, ultra-fine zirconia powder processing and toughened Y-TZP( Y<SUB>2</SUB>O<SUB>3</SUB> doped tetragonal ZrO<SUB>2</SUB> ceramics ), and investigating the propertieswear characteristics relation. Zirconia powders prepared by the hydrolysis method, which was the lowest production cost, showed the good formability and sinterbility. Y-TZPP containing 2.5-3.0mol% Y<SUB>2</SUB>O<SUB>3</SUB> gave higher fracture toughness and strength by the stress induced phase transformation toughening. The wear characteristics of Y-TZP grinding media depended strongly on the fracture toughness, strength and grain size, but not on hardness and density within the range of this experiment. It is considered that the excellent wear characteristic zirconia parts for grinding can be obtained by controlling the fracture toughness, strength and microstructure. To investigate these mechanism, the microstructures of worn areas were examined by SEM observations.

著者

井上 誠 東 泰助 小野木 伯薫 横田 勝 村田 安規 中平 敦

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.58, no.7, pp.407-411, 2011-07-15

参考文献数

8

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We have developed the Ag-Cu-Sn-Ni quaternary brazing filler metal having a low melting point, a high strength and a high ductility. Then, we produced wire saws composed of Ni-coated SUS304 wires, on which diamond abrasives are fixed with this brazing filler metal. We tried to slice the Si ingots using this wire saw. Good results were obtained for the application to the production of silicon wafers for solar cells. Accordingly, we focused on the basic experiments for further performance of the fixed abrasive diamond wire saws, leading to low cost of slicing technique of hard materials such as silicon and sapphire. In particular, we examined wettability, interfacial reaction and joint strength between Ag-Cu-Sn-Ni quaternary brazing filler metal and industrial metal plates such as Cu, Ni or flux coated SUS304.