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Volume 15, Issue 6
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[in Japanese], [in Japanese]1968 Volume 15 Issue 6 Pages 268-282
Published: October 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (12748K) -
Motoyuki Tokushita, Kikuo Tsuchiya, Kensuke Suehiro1968 Volume 15 Issue 6 Pages 283-287
Published: October 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe authors reported previously the sponge iron powder for powder metallurgy which was prepared from pyrite by means of a sequence of the following operations: flotation, roasting and treating with nitric acid, reduction of the purified pyrite cinder with hydrogen, and rolling and annealing of the reduced iron powder.
Furthermore, an attempt was made to cut the cost by employing H2-Co gas mixture as a reducing agent. And the authors has succeeded in improving the apparent density and the compressibility of the reduced iron powder by repeating the processes of powder rolling, grinding and annealling.
Consequently, they obtained the reduced iron powder having little carbon content and other impurites. The result showed that repeated powder rolling and annealling were effective for densification, and that it was preferable to anneal the powder at a comparatively lower temperature for the improvement of compressibility.
Iron powder obtained had compressibility as high as electrolytic iron powder, and the other properties were also satisfactory.View full abstractDownload PDF (3887K) -
Hiroshi Yamamoto1968 Volume 15 Issue 6 Pages 288-294
Published: October 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe author reported previously the manufacturing of Sendust alloy sheets by powder rolling or electric discharge sintering process.
So far as magnetic properties are concerned, the products are slightly inferior to the Sendust alloy melted, owing to the fact that the density of these samples is lower than that of the latter, and also to the fact that their chemical compositions were not controlled correctly.
In this experiment, the author examined some properties of sintered Sendust-alloys without or with the addition of phosphorous and titanium. Materials used were mother alloy-(6.4% Al, 11.71% Si, Fe balanced), electrolytic iron-, carbonyl iron-, red-phosphorous-, ferro-phosphorous-and ferro-titanium-powders.
The compacts of the Sendust alloy (5.3% Al, 9.7% Si, Fe balanced) were obtained by pressing the mixture of 83% mother alloy and 17% iron-powders. In these compacts, the electrolytic iron powder was found to be a better binder than the carbonyl iron powder.
Sintered Sendust-alloys showed the following excellent properties. But the effects of the addition of P and Ti were not so remarkable.
Effective permeability of sintered Sendust alloy sheets (0.71mm thick) was higher than that of Alperm sheets (0.6mm thick).
The Sendust sheet will be more superior to the Alperm sheet for the same thickness, since the frequency characteristic depends on the thickness. Electro-magnetic and physical properties of a typical sample are as follows : Um=20000, BHC=0.08 Oersted : Br=1900 Gauss : B10=7300 Gauss : D=6.49g/cm3 : ρ=133 μΩ-cm : Hv=496. This sample was sintered at 1150°C for 3hr in vacuum.View full abstractDownload PDF (3708K) -
Hideyuki Okinaka, Koji Kosuge, Sukeji Kachi1968 Volume 15 Issue 6 Pages 295-301
Published: October 25, 1968
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPhase equilibria in the manganowüstite (Fe, Mn) O system were established at 1260°K by varying the oxygen partial pressure from 10-20 to 10-10 atm., by using CO2-H2 gas mixtures. The nonstoic hiometry of (Fe, Mn) O has been determined by chemical analyses. Lattice constants and Néel temperature measurements were made on these nonstoichiometric manganowustites.
The theoretical formulas showing the equilibrium relation between the gas phase and the manganowüstite phase were calculated from the statistico-thermodynamics. The formulas thus obtained were in fairly good agreement with the experimental results obtained by the present authors and by Muan et al..View full abstractDownload PDF (463K) -
Kiyoshi Tamura, Shuij Wanikawa1968 Volume 15 Issue 6 Pages 302-307
Published: October 25, 1968
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn the atomizing method, powders having different characteristics can be produced by controlling the properties of the molten metals, atomizing medium and conditions. The purpose of this study was to elucidate the effects of these factors on powder characteristics.
The results were summarized as follows :
1. The average particle size decreased with increasing water velocity and the apparent density of the powder decreased when the powder was produced at higher water velocities.
2. The distribution curve of the particle size also shifted from coarse to fine and the apparent density decreased with decreasing surface tension of the molten metal.
3. With the increase of the temperature of the molten metal, the amount of fine powder (under 55μ) increased.
4. When a nozzle with a large diameter was used, the distribution curve of the particle size shifted from fine to coarse and the time required to pulverize a definite amount of the metal was reduced.View full abstractDownload PDF (2743K) -
Kiyoshi Tamura, Shuji Wanikawa1968 Volume 15 Issue 6 Pages 308-312
Published: October 25, 1968
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn order to improve the poor compactibility of atomized bronze powder, the authors re-ex-amined the producing process. First powders containing small amounts of sulfur were produced, then, these powders were subjected to oxidation and finally reduced. The powder obtained showed outstanding compactibility in comparison with that of those powders obtained by mixing each component powder. .
The results were summarized as follows:
1. The optimum oxidizing temperature was 800°C.
2. The retained sulfur in the powder decreased with increasing oxidizing time.
3. The optimum reducing temperature after oxidation was 550°C and the reduced cake was crashed easily.
4. Apparent density decreased with increasing sulfur content and oxidizing time.
5. Weight decrease by Rattler test was found in the low percent range and the powder was found excellent in comparison with conventional atomized bronze powders.View full abstractDownload PDF (1394K)
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