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Volume 29, Issue 6
Displaying 1-6 of 6 articles from this issue
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Koichi Chino, Masami Matsuda, Kazuhiko Kudo, Susumu Horiuchi1982 Volume 29 Issue 6 Pages 195-200
Published: August 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCompaction mechanism in pelletizing process was studied, and following results were obtained.
(1) A relationship between pellet density and compacting pressure was derived from a model based on powder particle deformation during the compacting.
(2) The model validity was confirmed experimentally using ionic and metallic crystal powders.
(3) It was found that deformation coefficient, the only empirical constant in the model, is determined by shear modulus of the powder particle for ionic crystal powders.
From these results, it was concluded that the relationship between the pellet density and the compacting pressure can be estimated analytically from the shear modulus for ionic crystal powders.View full abstractDownload PDF (1712K) -
Koichi Chino, Masami Matsuda, Kazuhiko Kudo1982 Volume 29 Issue 6 Pages 201-205
Published: August 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe factors affecting powder compact strength were investigated using potassium chloride and sodium chloride powders. These ionic crystals were studied in order to avoid the effect of impurity layer often formed on the surface of metal particle. The powders were sieved to 6 particle size ranges (25-550 μm) and compacted (0-500MPa). The following results were obtained:
1) Maximum compression strength of ionic powder compacts was approximately equal to that of a single crystal.
2) For the powders having the same particle size, compression strength was proportional to interparticle contact area which was calculated from powder compact density.
3) For the powder compacts having the same density, compression strength was inversely proportional to the square root of the particle size.View full abstractDownload PDF (358K) -
Naoichi Yamamoto, Masayoshi Horibe, Shin-nosuke Higashi1982 Volume 29 Issue 6 Pages 206-210
Published: August 25, 1982
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSFormation and stability of some kinds of simple cubic spinel ferrites in alkaline solution were investigated with hydrothermal technique. MgFe2O4 and CdFe2O4 are stable in a temperature range of 330°C to 600°C and 460°C to 600°C, respectively. MnFe2O4 is only stable below 100°C and it becomes disproportionate to an iron oxide and mangan-oxide around 150°C. NiFe2O4 and CoFe2O4 are stable from 80°C to 600°C and from 60°C to 600°C, respectively. In the case of ZnFe2O4 it was affirmed that the spinel structure is stable only when the alkaline solution is saturated with Zn(OH)42-.View full abstractDownload PDF (1450K) -
Vacuum-sintering of Cu-Al Powder Compacts in the Presence of CarbonYasuhiko Hashimoto, Shinichiro Ohmori, Koichiro Kohyama, Masato Kikuka ...1982 Volume 29 Issue 6 Pages 211-216
Published: August 25, 1982
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn order to obtain aluminum bronze sintering compact having good mechanical properties, the carbo-thermic reduction was applied to the sintering of Cu-Al powders which surfaces were covered with aluminum oxide layers.
Green compacts of (1) Cu-6.5 mass%Al prealloyed powder (A-powderl), (2) mixed powders of A and graphite (up to 0.5 mass%graphite), (3) Cu-7Al-7Ni-6Fe (mass%) prealloyed powder, (4) mixed powders of copper and Cu-1 1mass%Al alloy (Al content was 6.5 mass%) and (5) Ni-plated A-powders or mixed powders of A and nickel (Ni contents were both 2-3 mass%), were embedded in graphite powder and heated under a reduced CO pressure of 0.03 Pa for 10.8 ks.
The best result was obtained in the case of (4), where the strength and the ductility of the sintered products were high enough to those of the dense material (milled sheet) of the same composition.View full abstractDownload PDF (5343K) -
Shigenori Tanabe, Jiro Shibata, Masaharu Miyano1982 Volume 29 Issue 6 Pages 217-221
Published: August 25, 1982
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn order to obtain sintering compact with high strength, it is necessary to remove excessive amounts of carbon in cast iron powder. We investigated conditions of rust formation on the powder, which was soaked in water and dried. We also examined a decarburization process by oxygen contained in the rust. The results were as follows.
(1) Rust could easily adhere to the surface of the powder with a function of desired quantity of oxygen when the powder, registering between 150°-200°C, was soaked in water and then dried.
(2) Carbon was removed as mainly CO gas. This action of decarburizing ended when all the oxygen was consumed.
(3) In order to obtain powder containing desired carbon and less oxide, it is necessary to heat this powder at a temperature of 1000°-1050°C for 2 hours in vacuum.
(4) The cast iron powder decarburized in this method will be useful for powder metallurgy.View full abstractDownload PDF (2372K) -
Takeshi Sadahiro, Tetsuya Mitsuda, Sokichi Takatsu1982 Volume 29 Issue 6 Pages 222-226
Published: August 25, 1982
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSFracture toughness of WC-(4-20)%Ni alloys and WC-10%Ni alloys with different WC grain size (1.31-2.21μm) was compared with that of WC-Co alloy. Effect of various additions on the fracture toughness of WC-10%Ni alloy was also investigated.
The results obtained are as follows:
(1) Fracture toughness of WC-Ni alloy increases with the increase of the Ni content and the WC grain size.
(2) WC-Ni alloy shows a fracture toughness equal to WC-Co alloy in relation to hardness. However, for the same WC grain size, the WC-Ni alloy shows a lower hardness and a higher fracture toughness than those of WC-Co alloy. The reason is considered to be in that the binder phase of WC-Ni alloy has lower hardness and higher fracture toughness.
(3) By addition of Si, Ti, Cr and Mo which are soluble in Ni, the hardness of the WC-Ni alloy is increased. It is found that WC-Ni alloys containing 6%Si, 1-2%Ti, 5-10%Cr and Mo in the Ni binder show the same hardness and fracture toughness as the WC-Co alloy has.View full abstractDownload PDF (318K)
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