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Volume 12 (1965)
- Issue 6 Pages 219-
- Issue 5 Pages 183-
- Issue 4 Pages 139-
- Issue 3 Pages 93-
- Issue 2 Pages 55-
- Issue 1 Pages 7-
Volume 12, Issue 4
Displaying 1-3 of 3 articles from this issue
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Toshihiko Sato, Junzo Shimoiizaka1965 Volume 12 Issue 4 Pages 139-145
Published: August 25, 1965
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe dispersion of fine particles in organic solvent is an important process in paint industry, cosmetic industry and so on.
Fine particles in non-polar organic solvent such as cyclohexane, if they. are not aerophilic, settle rapidly by flocculation. Then, the following two methods have been applied to stabilize such a suspension ;
(1) The organic compounds, soluble in the solvent, are added directly to the suspension, as the dispersing agents.
(2) The organic compounds, soluble in water, are added to the aqueous suspension. The fine particles, being adsorbed by the agents on the surface, are filtrated and dried. Then, they are dispersed in organic solvent. This process is sometimes called the FLUSHING PROCESS.
The latter method, on which few systematic studies are undertaken, has been recently developed. The flushing process is applied upon the fine particles of α-ferric oxide. It is found that the particles coated with the monomolecular layer of oleate through the pretreatment in the aqueous suspension are very stable in cyclohexane.
The mechanism of the dispersion above remarked is explained in connection with the adsorption behavior of sodium oleate upon the fine particles of α-ferric oxide.View full abstractDownload PDF (420K) -
Tositaka Fujiyama1965 Volume 12 Issue 4 Pages 146-151
Published: August 25, 1965
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThis report relates to magnetic properties of sintered iron containing phosphorus. The effects, on sintered iron compacts, of forming pressure, the amount of hydrogen loss of iron powders, sintering temperature and times were investigated.
The iron powders used are made by reduction of iron ore. The amount of adding phosphorus, forming pressure, amount of hydrogen loss of iron powders are 0-2.5 (wt)%, 2-8 T/ cm2, 0.4-1.6 (wt)%, respectively.
Magnetic properties are improved by adding phosphorus, and the optimum ratio of it was 0.8-1.0 (wt)%b and are superior when sintered at 1, 300°C in hydrogen for 3hr. Maximum permeability and magnetic induction B 25, both increase with the sintered density, but maximum permeability of sintered iron containing much phosphorus tend to decrease. The quantities of phosphorus that produce maximum sintered density and maximum permeability are different for each forming pressure and the amout of hydrogen loss of used iron powder.View full abstractDownload PDF (388K) -
Hiroyasu Mitani, Keiichiro Shoji1965 Volume 12 Issue 4 Pages 152-158
Published: August 25, 1965
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAluimium bronze is one of the most useful copper alloys owing to its high strength and high corrosion resistance. However, it has scarcely been used as sintering materials. The present experiments were carried out in order to find what are the difficulties of the sintering of Cu-Al compacts and how to weed out these evils. For this purpose the dilatometric analysis, thermal analysis, microscopic examination and thermochemical calculation were carried out systematically using Cu-Al binary compacts which contain up to 67wt% Al.
Results obtained in these experiments were as follows :
1) Independent of Al-content in the Cu-Al compacts, an abnormal expansion appeared constantly at 548°C during sintering, which is the eutectic temperature of Cu-Al binary system.
2) The abnormal expansion increased with the increase of Al-content in the compacts up to 17wt% Al, at higher contents decreased with increase of Al-content, and finally disappeared at the eutectic composition of 67wt% Al.
3) The thermal analysis showed that the abnormal expansion was always accompanied by an abrupt exothermic reaction, led by a slight endothermic reaction of the eutectic. Judging from the direct measurement of the exothermic change, the abnormal expansion seems to be induced mainly by the exothermic reaction above 548°C.
4) The largest abnormal expansion and exothermic change were found in the compact containing about 17wt % Al, which corresponds to the composition of γ 2 phase.
5) From the microscopic examination and thermochemical calculation this exothermic change could be regarded as the heat of γ 2 formation, where Cu powder and Al powder combined catalytically in the presence of a liquid phase at 548°C or above during sintering.
In order to weed out this exothermic reaction, Cu-γ 2 compacts should be used for sintering. However, the difficulty of sintering may be expected in this case.View full abstractDownload PDF (1874K)
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