Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
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Volume 59, Issue 10
October
Displaying 1-8 of 8 articles from this issue
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  • Development of High Porosity Alumina Refractory Brick by Gelation of Slurry and Foaming Method
    Toru SHIMIZU, Kazuhiro MATSUURA, Harumi FURUE, Kunio MASTUZAKI
    2012 Volume 59 Issue 10 Pages 587-592
    Published: October 15, 2012
    Released on J-STAGE: January 10, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.587
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    Alumina has high heat resistance and corrosion resistance compared to silica, mullite and other ceramics. However, it has the high thermal conductivity of about 36 W/mK at room temperature, and necessarily decreases its thermal conductivity for application to refractory bricks. Therefore, high-porosity alumina refractory brick was developed using GS (Gelation of Slurry) method that has been already developed for production of high-porosity metal foam. Appling this method to production of alumina foams, the foams from 94 to 97.5 % porosity was produced, which had the compression strength from 0.1 to 1 MPa. The strength was almost proportional to the square of the densities. Its thermal conductivity was also proportional to the density and obeyed the Ashby-Glicksman model for the open cell structure, though it took the closed cell structure. Its thermal conductivity was about 0.1 W/mK when the density was 0.1 g/cm3. The high-porosity alumina foam achieved the enough thermally insulating property for the refractory brick, and applications will not be limited to the refractory brick application.
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  • Production of Hydrogen by Hydrolysis of Mg Chips
    Kunio MATSUZAKI, Youichi MURAKOSHI, Toru SHIMIZU, Shizuka NAKANO, Kota ...
    2012 Volume 59 Issue 10 Pages 593-597
    Published: October 15, 2012
    Released on J-STAGE: January 10, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.593
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    Hydrogen was produced by a hydrolysis reaction of Mg chips generated in cutting process. The reaction of Mg chips with pure water produced a little volume of hydrogen, but NaCl solution drastically improves the reaction. Hydrogen produced in NaCl solution increases with NaCl content and 750 ml of hydrogen per gram of Mg was obtained in NaCl solution with 2 M after 300 min, corresponding to the conversion yield of 80 %. A decrease in size of Mg chip and an increase in volume of NaCl solution also improve the hydrogen production performance. After reaction in NaCl solution, formation of Mg(OH)2 was observed and MgCl2 was not found. This means that the amount of NaCl does not change during the reaction. The NaCl solution after the reaction can be reused for the production of hydrogen by adding Mg and H2O.
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  • Characteristics of TiN Particle Dispersed Magnesium Composite Materials Produced by Hot Extrusion
    Jianlong YU, Ken-ichi TAKAGI, Takuya FUJIMA, Ai MOMOZAWA
    2012 Volume 59 Issue 10 Pages 598-604
    Published: October 15, 2012
    Released on J-STAGE: January 10, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.598
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    0-10 vol% TiN added Mg composite powders were fabricated by mechanical alloying. The effects of the hot extrusion temperature and the TiN content on the mechanical properties of the hot extruded Mg composite were investigated. The morphology of the mechanical alloyed composite powders was studied by secondary electron images of the scanning electron microscopy. The phase formation of the mechanical alloyed composite powders and the hot extruded composite was investigated by the Cu Kα X-ray diffraction. The microstructure of the hot extruded composite was studied by the optical microscope and mechanical properties of the composites were evaluated by the density, Vickers hardness and the tensile strength. As a result, the 10 vol% TiN added Mg composite hot extruded at 773 K showed the hardness of HV(1) being 127 while the maximum tensile strength of 463 MPa was obtained for the 5 vol% TiN added Mg composite due to the grain size refinement and the dispersion-strengthening by TiN. Further increase of TiN might reduce the Mg grain bonding strength, resulting in the decrease of the tensile strength at 10 vol% TiN addition. These values are higher than those of commercial Mg alloys so that the new Mg composites are promising Mg materials for practical applications in near future.
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  • Preparation of Cordierite by Corrosion Reaction Synthesis
    Daichi SASAKI, Kosuke HIGASHITANI, Yasuhiro OSAFUNE, Osami SERI
    2012 Volume 59 Issue 10 Pages 605-608
    Published: October 15, 2012
    Released on J-STAGE: January 10, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.605
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    The electrochemical method named as the corrosion reaction synthesis has been tried to prepare the cordierite powder. As metallic magnesium, aluminum chloride and tetraethyl orthosilicate were mixed in ethanol, the corrosion product containing hydroxide of aluminum, magnesium and silicon was obtained. The product was hydrolyzed and fired. The X-ray diffraction, the particle size measurement and the scanning electron microscope revealed that the cordierite of which average size was about 10 μm was obtained at more than 1473 K. The magnesium dissolution, the catalytic effect of aluminum chloride, and the mixing effect of three elements above were considered from the electrochemical point of view.
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  • Microstructural and Electrical Properties of Copper-titanium Alloy Dispersed with Carbon Nanotubes via Powder Metallurgy Process
    Hisashi IMAI, Katsuyoshi KONDOH, Shufeng LI, Junko UMEDA, Bunshi FUGET ...
    2012 Volume 59 Issue 10 Pages 609-615
    Published: October 15, 2012
    Released on J-STAGE: January 10, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.609
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    Microstructural and electrical properties of copper alloy (Cu-Ti) with carbon nanotubes (CNTs) prepared by powder metallurgy (P/M) process have been investigated. The Cu-0.5 mass% Ti pre-alloyed powder was made by water atomization process. The powders coated with un-bundled CNTs by using the zwitterionic surfactant solution containing CNTs were consolidated at 1223 K in vacuum by spark plasma sintering, and then extruded at 1073 K. The P/M Cu-Ti alloy without CNTs (monolithic alloy) had 202 MPa yield stress (YS) and 42.5 International-Anneld-Cupper-Standard % (IACS%) conductivity. The extruded Cu-Ti composite alloy containing CNTs revealed small decreased of YS compared to the monolithic Cu-Ti alloy. On the other hand, the composites revealed a higher electrical conductivity than that of the monolithic alloy. For example, Cu-Ti with 0.19 mass% CNTs showed 175.8 MPa YS and 83.5 IACS% conductivity. In the case of the Cu-Ti composite with CNTs, intermetallic compounds such as Cu4Ti and TiC were observed around CNTs by TEM-EDS analysis. The amount of the titanium solid solution in the above Cu-Ti composite alloy matrix was 10 % of the monolithic Cu-Ti alloy, and resulted in the remarkable increment of its electrical conductivity.
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