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Volume 41, Issue 10
Displaying 1-8 of 8 articles from this issue
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Katuo Saitou2004 Volume 41 Issue 10 Pages 714-721
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSProduction of ultrafine metal particles (UFPs) using an RF plasma method is a promising one, but the effects of experimental conditions on the production of UFPs are not well understood yet. In this paper, we produced nickel UFPs by means of an Ar-H2 RF plasma and investigated the effect of mean diameter of raw powder on the evaporation ratio in the plasma, the relationship between the generation ratio of UFPs and the collection sites in the apparatus, the effects of hydrogen content in plasma and the pressure in the apparatus on the specific surface area of UFPs.
The evaporation ratio of raw powder is reduced with increasing the particle diameter and decreasing the pressure in the apparatus. The generation ratio of UFPs was the highest at the collection site near the tail of plasma. Specific surface area of UFPs increased with hydrogen content in the plasma when the pressure in the apparatus was low, whereas it is not dependent on hydrogen content when the pressure was high. The mean particle diameter of UFPs calculated from the specific surface area had a good correlation with that measured from TEM photomicrographs.View full abstractDownload PDF (3014K) -
Katuo Saitou, Akira Suzuki2004 Volume 41 Issue 10 Pages 722-729
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn this study, ultrafine nickel particles (UFPs) were produced using an Ar-9.6%H2 RF plasma by feeding the raw powder of 10μm diameter. The effect of powder feeding rate on the yield and the specific surface area of UFPs was investigated by varying the powder feeding rate in two orders of magnitude (0.07-7.19g/min). The composition and flow rate of plasma gas, the power of plasma and the internal pressure of apparatus were kept constant during the experiments. Furthermore, the applicable range of Brownian coagulation mechanism was discussed. The UFPs were isolated and spherical in shape when the powder feeding rate was low; while they were collided and coalesced particles when the powder feeding rate was high. The specific surface area of UFPs was the highest at a low feeding rate, although it was not dependent on the collection sites when the powder feeding rate was higher than 0.2g/min. The present experiments suggested that the particle formation is controlled by Brownian coagulation in a narrow range of powder feeding rate at a relatively low value.View full abstractDownload PDF (2647K) -
Shuya Nakao, Masaru Kojima, Kenji Tanaka2004 Volume 41 Issue 10 Pages 730-737
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSConstrained sintering of a substrate with a sandwich structure, which was the laminated inner-constraining alumina layer between the glass-alumina mixed layers, has been studied. The influence of specific surface area of the particles and porosity of inner constraining particle layer upon sintering shrinkage was investigated. Specific surface area of the alumina powder for the inner constraining particle layer could be changed by grinding and blending two different particle size powders. As for the debinded sheet used with ground alumina powder, the pore distribution was sharp, and the bending strength was proportional to the specific surface area. In the case of inner constraining particle layer used with ground alumina powder, penetration length of molten glass from glass-alumina mixed layers obeyed Kozeney-Carman's equation. On the other hand, as for the debinded sheet with particle size blended powder, the effects of specific surface area on the bending strength and the penetration length of molten glass differed from the results of the grounded one. Sintering shrinkage in X-Y direction of the sandwhich substrate was basically related to the bending strength of debinded alumina powder sheet for inner constraining particle layer in both cases.View full abstractDownload PDF (910K) -
Selective Synthesis of Phillipsite from Fly Ash and Rice Husk Ash Prepared by Hydrothermal TreatmentKunihiro Fukui, Mayumi Takiguchi, Masashi Ugumori, Tatsunori Noriyasu, ...2004 Volume 41 Issue 10 Pages 738-744
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSZeolites were synthesized trom the mixture of the fly ash with a relatively low silica content and the rice husk ash by a hydrothermal treatment method. The fraction of phillipsite in the formed zeolite was increased with the fraction of rice husk ash whereas the fraction of by-product hydroxysodalite was decreased. Phillipsite can be selectively synthesized from the mixture, using new or recycled NaOH aqueous solutions. It is found that the product powder prepared from the mixture of the fly ash and the rice husk ash has almost the same ammonium ion adsorption capacity as the product from the mixture of the fly ash and pure silica powder. Phillipsite can be synthesized from the mixture of the fly ash and the rice husk ash for shorter treatment time than that from the mixture of the fly ash and pure silica powder, being independent of NaOH concentration.View full abstractDownload PDF (2071K) -
Takeo Kajishima2004 Volume 41 Issue 10 Pages 745-749
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (2186K) -
2004 Volume 41 Issue 10 Pages 757-758
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (4221K) -
Junya Kano2004 Volume 41 Issue 10 Pages 759-761
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (5060K) -
[in Japanese]2004 Volume 41 Issue 10 Pages 763
Published: October 10, 2004
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (131K)
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