Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
Volume 14, Issue 5
Displaying 1-5 of 5 articles from this issue
  • C.G. Goetzel, J.B. Rittenhouse
    1967 Volume 14 Issue 5 Pages 195-202
    Published: August 25, 1967
    Released on J-STAGE: December 04, 2009
    JOURNAL FREE ACCESS
  • Copper-base Lininng Material
    Seiichi Ishida, Tsuyoshi Taniuchi
    1967 Volume 14 Issue 5 Pages 203-212
    Published: August 25, 1967
    Released on J-STAGE: May 22, 2009
    JOURNAL FREE ACCESS
    A new sintered copper-base brake lining for disc brake of railroad cars, torque converters and transportation machines has been developed.
    The lining material contains copper, tin and lead as metallic component, and graphite and silica or alumina as non-metallic one. Copper and tin form a wear resistant matrix as "Sintered bronze". Various characteristics could be obtained by incorporating the solid lubricant (graphite and lead) and wear resistant element (silica and alumina).
    Coefficient of friction and wear rate of the lining materials are given in dry and wet conditions.
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  • On the Sintered Steel with Reduced Concentration of Alloying Elements
    Toshihiro Kinoshita, Yoichi Tokunaga, Isao Taniguchi
    1967 Volume 14 Issue 5 Pages 213-220
    Published: August 25, 1967
    Released on J-STAGE: July 12, 2010
    JOURNAL FREE ACCESS
    The sintering and age-hardening-characteristics of 18 Ni-7Co-5Mo sintered steel were reported before. In the present paper, a composition of 78Fe-12Ni-5Co-5Mo was chosen for examining the structural and mechanical properties of the sintered steel which was reduced effectively in the amount of alloying elements. Specimens were prepared by mixing reduced iron powder with powders of alloying element, compacted mainly at 6t/cm2 and sintered in hydrogen for lhr at 1300°C. Subsequently, the sintered compacts were aged for 5hrs at 500°C. The results are summarized as follows ;
    1) The variations of concentration of alloying elements in the sintered steel were determined by electron-probe' microanalyses. The concentrations were 8-12% for nickel, 4-6% for cabalt and for molybdenum. From these results, therefore, the structural characteristics of the sintered compact may be estimated as follows ; Ms-temperature ; 465-260°C, age-hardenability ; 3-14 HRc and tensile strength after aging; 80-150kg/mm2.
    2) The mechanical properties of sintered steel are mostly determined by chemical composition and also by relative porosity. An empirical relationship is established between the porosity and yield strength of sintered steel, given by; Y. Ss/Y. Sm=1-1.58ε2/3, Where, Y. Ss and Y. Sm are the yield strengths of the sintered and forged steel respectively, and & is relative porosity. This relationship shows good agreement among the results obtained with 12Ni-5Co-5Mo and 18Ni-7Co-5Mo steels. The transverse-rupture strength, however, is markedly affected by the stress concentration generated by pores. Consequently, the ratio of the strength of the sintered steel to that of the forged steel is lower than the ratio of tensile property.
    3) Addition of copper to sintered steel resulted in higher tensile strength, but in lower transverse-rupture strength, which might be due to the improved age-hardenability in the martensitic matrix. Attempts to obtain compacts with higher density by adding phosphor and boron has been unsuccessful, probably due to the extremely brittle nature of the sintered compacts.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    1967 Volume 14 Issue 5 Pages 221-225
    Published: August 25, 1967
    Released on J-STAGE: December 04, 2009
    JOURNAL FREE ACCESS
    Fine particles of high-purity barium titanate from a minimum of 500A upwards were prepared. by the thermal decomposition of barium titanyl oxalates, BaTiO(C2O4) 2⋅4H20, at 600-1100°C. The effective dielectric constant was measured with the particles dispersed in Araldite resin. The following results are of interest: (1) In the case of fine particles of 500-700A, the effective dielectric constant delineates a smooth curve with temperature and the ferroelectric Curie peak moves to low temperature. (2) From X-ray diffraction analysis, the tetragonality decreased with decreasing particle size, thus leading to cubic symmetry.
    A brief discussion was given to the correlation between the decrease in tetragonality and the shift of the Curie point.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    1967 Volume 14 Issue 5 Pages 226-230
    Published: August 25, 1967
    Released on J-STAGE: May 22, 2009
    JOURNAL FREE ACCESS
    Pressure-squeezing effect on the ferro-paraelectric transition of barium titanate and a ceramic body was studied. The remarkable experimental results are as follows : (1) The pressure-sque-ezed barium titanate had a smaller heat of transition at the Curie temperature and a remarkable low dielectric constant which did not show a steep rise at the Curie temperature, 120°C. (2) The steep rise was not observed even when the pressure-squeezed sample had been annealed at 1200°C for 2 hr. (3) The pressure-squeezed sample showed no P-E hysteresis loop and had tetragonal symmetry characterized by broad peaks in X-ray patterns even above the Curie temperature.
    It appears that the notable pressure-squeezing effects, i.e., decrease in grain size and formation of mechanical stresses among the crystal grains and of lattice defects, especially stacking faults, cause the hindrance to the displacement of ions and hence to the ferroelectric arrangement of spontaneous polarization.
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