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Volume 26, Issue 4
Displaying 1-7 of 7 articles from this issue
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[in Japanese], [in Japanese], [in Japanese]1979 Volume 26 Issue 4 Pages 123-130
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (6258K) -
The effects of heating rate of atomized dropelets and addition of less volatile solvent on the particle shapeAkio Kato, Hiroyuki Ishimatsu, Yoko Suyama1979 Volume 26 Issue 4 Pages 131-135
Published: June 25, 1979
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSFormation of metal oxide powders by spray-pyrolysis technique from an ethanol solution of the metal nitrate was investigated to elucidate the effects of heating rate of atomized droplets and addition of glycerine to the solution on the particle shape of the products.
α-Fe2O3 particles produced were spherical under a low heating rate and were inflated as the heating rate increased. At a high heating rate the particles fractured to irregular flakes.
In the formation of MgO, ZnO, and Co3O4 powders, on the other hand, the particles maintained the spherical form even under the high heating rate.
Addition of glycerine to the ethanol solution made α-Fe2O3 particles spherical and ZnO particles porous.View full abstractDownload PDF (5369K) -
Yoshiharu Morimoto, Takuo Hayashi, Hiroshi Numata1979 Volume 26 Issue 4 Pages 136-142
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn this paper, we study the effects of punch speed and punch mass on the dynamic compaction of powders. First, simple theoretical calculations are made, and then, for a comparison, the strain during dynamic compaction of copper powders is measured by Moire method, using the high speed camera.
As a result, when the kinetic energy of each punch is equal to each other, following conclusions are obtained.
(1) During dynamic compaction, the higher the punch speed is, the higher the density is. But, after dynamic compaction, the lower the punch speed is, the higher the density is. These may be dependent on the properties of the shock wave and the viscosity of powders.
(2) Even though the kinetic energy of each punch is equal to each other, different punch speed leads to the different density distribution in the compacted powders. When the punch speed is low, the uniform density distribution is obtained.View full abstractDownload PDF (3465K) -
Mikio Fukuhara, Hiroyasu Mitani1979 Volume 26 Issue 4 Pages 143-148
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSintering characteristics of TiNx-Ni mixed powder compacts were studied by heating them in gas atmospheres of nitrogen, hydrogen or argon, or in vacuum.
The shrinkage during sintering was considerably disturbed by the liberated nitrogen gas from the compacts, whereas in lower value for x of TiNx, the gas diffused into TiN, grains up to TiN0.99 without denitrification. So that the shrinkage was remarkably promoted not only in vacuum, but also in hydrogen and argon. While, the nitrogen atmosphere hindered the shrinkage.
The Ni concentration and x value in formula TiNx showing the maximum sintered density in the sintering condition at 1500°C for 60min. were approximately 15 wt% and 0.8, respectively.View full abstractDownload PDF (1908K) -
Formation and Magnetic Properties of γ-Fe2O3 Particles Coated by Cobalt FerriteMikio Kishimoto, Toshinobu Sueyoshi, Susumu Kitaoka, Kunio Wakai, Masa ...1979 Volume 26 Issue 4 Pages 149-152
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAcicular γ-Fe2O3 particles were treated at 90°C in alkali solution containing CO2+ and Fe2+. The coercivity of resultant particles remarkably increased with increasing CO2+/Fe2+ ratio, and reached a maximum value in the vicinity of 0.4 to 0.5. The increase of coercivity was attributed to the magnetic anisotropy of iron-cobalt ferrite which was considered to crystallize at the surface of γ-Fe2O3. The magnetic properties of γ-Fe2O3 particles coated by iron-cobalt ferrite, such as a variation of coercivity in annealing at 60°C or printing effect, were extremely stable compared with those of cobalt-substituted iron oxides.View full abstractDownload PDF (1447K) -
Nobumasa Ohshima, Yoshio Enoki1979 Volume 26 Issue 4 Pages 153-157
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA new photoconductive material suitable for an EL-PC type X-ray image converting panel was developed. The material was obtained by activating a mixture of CdSe, ZnS and ZnO with Cu as an activator and chlorine and bromine as co-activators. In this method, an addition of ZnS, which makes a solid-solution with CdSe, was effective to increase the threshold voltage of the material, that of ZnO, which suppresses excessive sintering at the firing step, was effective to decrease the particle size, and the optimum amounts of ZnS and ZnO were effective to improve the photosensitivity of the material. The X-ray image converting panel for which the material was applied had improved characteristics in brightness, contrast, threshold sensitivity and resolution.View full abstractDownload PDF (1311K) -
A. Takei, K. Kurosu, M. Senna, H. Kuno1979 Volume 26 Issue 4 Pages 158-161
Published: June 25, 1979
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSA method for the direct measurement of compressive strength of a single granule was developed and applied to model spherical granules with different sizes and strengths. A ball mill method was also used for evaluating granule strength for practical purposes. For a series of equal sized granules prepared by the same method, the rate of size reduction by ball-milling varied linearly with the compressive strength of a single granule on log-log plots.View full abstractDownload PDF (240K)
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