Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
Search
Advanced search
OR
Browse
Search
Volume 61, Issue 9
September
Displaying 1-10 of 10 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Paper
Paper
  • Effect of CaO and SiO2 Inter-additives on the Magnetic Properties of Ca–La–Co M–type Ferrite Sintered Magnets
    Gaku OBARA, Hirotsugu HAMADA
    2014 Volume 61 Issue 9 Pages 431-436
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.431
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    ABSTRACT

    The effects of CaO and SiO2 inter-additives on the densities, the average particle size and the magnetic properties of Ca–La–Co system ferrite anisotropic sintered magnets are discussed. The results show that the magnetization of sintered magnets having the same density decrease with an increase in the ratio of SiO2 to CaO inter-additives while the non-magnetic material α–Fe2O3 is formed with an increase in the ratio. On the one hand, the coercivity HcJ of Ca–La–Co system sintered magnets increase with an increase in the SiO2 additive owing to the diminishing average particle size of sintered magnets. On the other hand, HcJ of Ca–La–Co system sintered magnets decrease with an increase in the CaO inter-addition since the crystal growth of the sintered magnets occurs due to the CaO inter-addition.
    View full abstract
    Download PDF (591K)
  • Microstructure and Mechanical Properties of TiAl3/Al2O3 in situ Composite by Combustion Process
    Hiroshi FUJIWARA, TRAN Duc Huy, Reo YOSHIDA, Do Thanh Binh, Hiroyuki M ...
    2014 Volume 61 Issue 9 Pages 437-440
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.437
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    ABSTRACT

    The microstructure and mechanical properties of TiAl3/Al2O3 in situ composite prepared via a combustion process were investigated in detail. Pure Al powder and TiO2 powder (molar ratio 13 : 3) were mechanically milled at 300 rpm for 18 ks. The milled powders were cold-pressed at 200 MPa for 0.3 ks and then green compact were sintered at 923 − 1173 K for 1.8 ks under Ar atmosphere. The microstructure of the sintered compact was analyzed using XRD, SEM and TEM/EDS, and the mechanical properties were evaluated using Vickers hardness and indentation fracture toughness tests. The compacts sintered at temperatures below 973 K consisted of a TiAl3 phase and remaining Al and TiO2 phases, while those sintered at temperatures above 1023 K consisted of a TiAl3 matrix, dispersed Al2O3 particles, and a plate-like Ti3Al phase. In addition, the compacts sintered above 1023 K had a higher hardness (approximately 800 Hv) compared to that of the TiAl3 single-phase compact (450 Hv). The fracture toughness of the TiAl3/Al2O3 composite was also approximately twice that of the TiAl3 single-phase compact. This improvement in the hardness and toughness is attributed to the microstructure of the composite, particularly the formation of dispersed Al2O3 particles and the Ti3Al plate-like phase in the TiAl3 matrix.
    View full abstract
    Download PDF (1160K)
Special Issue: Development of Nanomaterials with Energy-saving Green Processes and their Applications
Summarization
Review
  • Synthesis of ZnO Particles with Hierarchical Structures
    Noriko SAITO
    2014 Volume 61 Issue 9 Pages 443-447
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.443
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    ABSTRACT

    Solvothermal synthesis methods, using a mixture of ethylene glycol (EG) and water as the solvent, of ZnO spherical and flower-like particles having hierarchical nanostructures are reviewed. The preparation conditions and the nanostructures are summarized and the microscopic characterization of the hierarchical structures is explained. The ratio of EG to water influenced on the formation of the hierarchical structures: EG restricts the growth of ZnO microcrystals and promotes the self-assembly of small crystallites into spheroidal particles, and high water content results in hollow spheres. The application of the ZnO powder to a gas sensing device for volatile organic compounds gases is discussed.
    View full abstract
    Download PDF (1202K)
Review
  • Cutting-edge High Temperature Ceramics of Modified Aluminum Titanate with Low Thermal Expansion
    Masahiro FUKUDA, Masahide TAKAHASHI
    2014 Volume 61 Issue 9 Pages 448-453
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.448
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    ABSTRACT

    Aluminum titanate (AT) ceramics exhibit a high melting point and an excellent thermal shock resistance. Therefore, they have long been expected to serve as useful refractory materials. AT ceramics have been so far known to have two fatal disadvantages; low fracture strength owing to poor sinterability and thermal decomposition. When the AT ceramics are kept at temperatures of 1123 − 1553 K for more than several tens hours, they decompose into rutile (TiO2) and corundum (Al2O3). Many attempts to improve their thermal and mechanical properties have been made by introducing various metal oxides containing Si, Mg, Zr and so on to them, AT ceramics with satisfactory features have not been realized yet. Recently, the feldspar-doped AT (f–AT) ceramics are prepared through liquid phase sintering process possess both a good thermal stability and better mechanical strength in addition to the low thermal expansion, that are brought about the microstructure design and chemical modification of f–AT ceramics. In addition, Al2TiO5–MgTi2O5 ceramics doped with alkaline feldspar (f–MAT) was found to be a decomposition free ceramics over 300 hours of heat treatment at 1373 K in an ambient atmosphere. The decomposition free f–MAT ceramics is expected for variety of high temperature applications including diesel particulate filters. In this article, recent progresses on doped-AT ceramics will be reviewed.
    View full abstract
    Download PDF (1254K)
Review
  • Nature-Mimetic Flux Innovation of Functional Inorganic Crystals and Layers for Green Energy & Environmental Materials
    Katsuya TESHIMA, Nobuyuki ZETTSU, Hajime WAGATA, Shuji OISHI
    2014 Volume 61 Issue 9 Pages 454-459
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.454
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    ABSTRACT

    Functional devices for energy and environmental applications have been attracted increasing attention in recent decades. Those devices are usually composed of a bunch of sophisticated materials which are often prepared by complex fabrication processes. It is important to prepare high-quality materials and connect them with good interfaces which don’t interrupt the diffusion of atoms and energy carriers by simple procedures. In this regards,our group has focused on growing high quality inorganic crystals by flux method. The advantages of flux method are growth of high-quality crystals without thermal strain, relatively low-temperature process, and simple experimental equipment. These advantages match with crystal growth not only in lab scale but also to industrial scale. In fact, we have grown many inorganic crystals for energy and environmental applications, and some of them are being tried to scaling up for industrial production. Our group has recently developed the flux method to thin film fabrication process which is named “flux coating method”, and fabricated many crystal layers with good interfaces between crystals and substrates. In this report, we introduce the series of grown crystals and fabricated crystal layers in addition to their future applications.
    View full abstract
    Download PDF (1603K)
JSPM Announcements
  • Errata
    2014 Volume 61 Issue 9 Pages 461-
    Published: September 15, 2014
    Released on J-STAGE: November 20, 2014
    DOIhttps://doi.org/10.2497/jjspm.61.461
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    About 2 papers of Vol.61, No.6 journal published in June 2014, the received date should be corrected.

    p.281
    Title: Effect of Oxygen Content in WC–FeAl Powders on Microstructure and Mechanical
            Properties of Sintered Composites Fabricated by Pulse Current Sintering
            Technique
    Authors: Ryoichi FURUSHIMA, Kiyotaka KATOU, Setsuo NAKAO, Zheng Ming SUN,
              Koji SHIMOJIMA, Hiroyuki HOSOKAWA and Akihiro MATSUMOTO

      Wrong: Received September 20，2014
       Right:  Received September 20，2013

    p290
    Title: Microstructure and Strength of Fe–2%Cu–0.8%C Sintered Steel using Fe–Cu Alloy
            Powder
    Autors: Taku IWAOKA and Akira FUJIKI

      Wrong: Received November 20，2014
       Right: Received November 20，2013

    View full abstract
    Download PDF (185K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top