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 57, Issue 9
September
Displaying 1-10 of 10 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Paper
Paper
  • DC-Biased Properties of Powder Cores using a Nonmagnetic Grain Boundary Model
    Susumu Handa, Yasuo Oshima, Kouta Akaiwa
    2010 Volume 57 Issue 9 Pages 593-600
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.593
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    DC-biased magnetic properties of Fe-3 mass % Si powder cores were investigated using a nonmagnetic grain boundary (NMGB) model. The powder was prepared by gas atomization. DC initial BH loops were measured and differential permeability was calculated at each magnetic force H. The values were compared with the NMGB-model considered from particle size distribution, body-centered cubic lattice situation and gap width distribution. The calculated values were in good agreement with measured values, which had intrinsic permeability: 3000, aspect ratio: 1.0 and geometric mean gap width: 0.41 μm. The relative inaccuracy of differential permeability was from -5.5 to 5.3 % between H=0.6 and 16 k A/m.
    View full abstract
    Download PDF (1839K)
  • Effects of Powder Sphericalization on DC Biased Properties of Powder Cores and Modeling
    Susumu Handa, Yasuo Oshima, Kouta Akaiwa
    2010 Volume 57 Issue 9 Pages 601-609
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.601
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Effects of powder sphericalization on DC biased properties of powder cores have been investigated and simulated using a nonmagnetic grain boundary (NMGB) model. Water atomized iron powder and Fe-6.5 mass % Si powder have been sphericalized by a powder surface modification system. Aspect ratio has got smaller depending on rotational speed. Aspect ratio of the former at rotational speed 8000rpm and 180 sec have gotten as 1.29 equivalent to gas atomized iron powder and DC biased property has been improved. They have been compared with values calculated by the NMGB model. The relative inaccuracy has been within 4.23 %. Aspect ratio of the latter (Fe-6.5 mass % Si powder) has had smaller with higher rotational speed, while DC biased property has not been improved. They have been compared with values calculated by the NMGB model. The relative inaccuracy has been within 4.68 %. The gap width distribution has been compared between calculated and measured values. The relative inaccuracy of the average gap width has been 5.17 % on the iron powder core and 78.3 % on the Fe-6.5 mass % Si powder core.
    View full abstract
    Download PDF (1813K)
  • Influence of Preparation Method of Ag/Al2O3 Based Catalyst on Metal Coating
    Satoshi Kishida, Dong-Ying Ju
    2010 Volume 57 Issue 9 Pages 610-617
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.610
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The γ-Al2O3 and AgCl/Al2O3 catalyst powders were coated on a stainless steel substrate and influences of preparation methods on coating and NOX reduction were studied. The stainless steel SUS304 was coated by Electrophoretic Deposition Method using dehydrated aluminum nitrate as a binder. The AgCl/Al2O3 catalyst was produced by three kinds of methods, and the difference in the NOX reduction catalyses of coated samples was examined. XRD and SEM were used to study the crystalline structure and cross-section of the coatings. The coatings of γ-Al2O3with the thickness of 3-5 μm and AgCl/Al2O3 catalyst with the thickness of 3-8 μm were made on the surface of SUS304 plate without exfoliation. The NOX conversion of the coated sample with catalyst was about 70 % at the maximum. Furthermore, there was a peak in NOX reduction at the different temperature in the case of the catalyst produced under the conditions A.
    View full abstract
    Download PDF (1218K)
  • Effects of Kind of Added Carbides on Thickness and Morphology of β-Free Layer Formed in WC-TiN-Co Cemented Carbide
    Tomo Uchikanezaki, Hiroki Hara, Toshiyuki Takahashi, Koji Hayashi
    2010 Volume 57 Issue 9 Pages 618-625
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.618
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The crack extension resistance and plastic deformation, i.e., the life of CVD-coated cemented carbide tool are greatly affected by the thickness of β(WC-TiN-XC solid solution, XC: added carbide)-free layer near the tool corner as well as near the tool flat surface, and by those ratio, i.e., the morphology of the layer. In this study, the powder compacts of WC-TiN-Co added with six kinds of carbides were firstly sintered in Ar atmosphere of 1.3 kPa at 1693 K for 3.0 ks, and the surface layer of sintered compacts were ground by 0.5 mm thickness so that the altered surface layer generated mainly in the porous state by the sintering was removed. Then, such compacts were re-sintered mainly in vacuum of 10 Pa at 1693 K for 0∼14.4 ks.
    The main results were as follows. (1) The thicknesses near the flat surface and the corner were both in the order of Cr3C2 > NbC > Mo2C > ZrC > TiC > TaC and Cr3C2 > Mo2C > ZrC > TiC > NbC > TaC, respectively, irrespective of re-sintering time. Namely, the orders were different with each other. (2) The thickness near the corner for periodic table group-4 metal carbides (TiC, ZrC) and group-6 metal carbides (Cr3C2, Mo2C) was smaller than that near the flat surface at short re-sintering and/or medium time, but became larger at longer time. The thickness near the corner for group-5 metal carbides (NbC, TaC) was always smaller than that near the flat surface. However, the thickness as far as for Cr3C2 became larger near the corner than near the flat surface even at short re-sintering time, and for TaC the thickness difference between both areas became considerably smaller, when the initial nitrogen content of the specimen was increased by controlling N2 pressure in the first sintering furnace. (3) The results of the item (2), etc., suggested that the rate-determining step for the formation of β-free layer is not easy to determine: it depends on the kind of added carbide, the initial nitrogen content, sintering time (in-situ nitrogen content near the boundary of β-free layer), etc.
    View full abstract
    Download PDF (1157K)
Special Issue: New Developments of Magnetic Materials in Environmental, Nanotechnology, and Biomedical Fields
Summarization
Paper
  • Effect of Ni-Stearate Addition on Magnetic Properties of Anisotropic BaFe2 W-type Ferrites
    Hiroshi Yamamoto, Jun Sasaki
    2010 Volume 57 Issue 9 Pages 629-635
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.629
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    An experiment was carried out to investigate the effect of Ni-Stearate as a reducing agent on the magnetic and physical properties of anisotropic BaFe2-W type ferrite magnets. It was found that the magnetic properties of BaFe2-W type hexagonal ferrite were improved by adding 0.5 wt% of Ni-Stearate, 0.5 wt% of SiO2, and 0.5 wt% of CaO together. The optimum conditions for making magnets were as follows; Chemical composition: BaO · 8.5Fe2O3, semisintering condition: 1350°C×4.0 h in nitrogen gas atmosphere, drying condition: 190°C×2.0 h in air, sintering condition: 1180°C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties of a typical sample were Jm=0.47 T, Jr=0.42 T, HcJ=203.5 kA/m, HcB=192.3 kA/m, (BH)max=31.5 kJ/m3, Tc=484°C. The lattice constants of this compound were a=5.905×10-10 m, c=32.62×10-10 m, and c/a=5.523.
    View full abstract
    Download PDF (1312K)
  • Fabrication of FePt/SiO2 Composite Magnetic Beads
    Teruaki Fuchigami, Ryo Kawamura, Yohtaro Yamazaki, Yoshitaka Kitamoto, ...
    2010 Volume 57 Issue 9 Pages 636-641
    Published: 2010
    Released on J-STAGE: October 08, 2010
    DOIhttps://doi.org/10.2497/jjspm.57.636
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The present paper describes effects of organic molecules such as polymers and low molecular surfactants for chemical synthesis of magnetic core-shell FePt/SiO2 composite microspheres for biomedical applications such as the magnetic hyperthermia and the magnetically guided drug delivery system in cancer therapy. We obtained FePt/SiO2 composite microspheres approximately 330 nm in diameter with a thin shell of 5 nm in thickness by synthesizing FePt nanoparticles on silica microspheres modified with polydiallyldimethylammonium chloride (PDDA). The magnetic shell of 5 nm in thickness is a nanohybrid composed of FePt nanoparticles of approximately 3-4 nm in size and a single-layer of the polymer. The FePt/PDDA/SiO2 core-shell particles exhibit ferromagnetic features at room temperature because the Fe-Pt nanoparticles with ordered-alloy phase are formed with the aid of PDDA despite of small size. The blocking temperature depends on the synthesis temperature of FePt nanoparticles.
    View full abstract
    Download PDF (1300K)
JSPM Announcements
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top