TANSO
Online ISSN : 1884-5495
Print ISSN : 0371-5345
ISSN-L : 0371-5345
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Volume 1986, Issue 125
Displaying 1-5 of 5 articles from this issue
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  • Stability and Preparation Condition of CuCl2-and FeCl3-Graphite Intercalation Compounds
    Masahiko Ohira, Takayuki Terai, Yoichi Takahashi
    1986 Volume 1986 Issue 125 Pages 45-52
    Published: April 25, 1986
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.7209/tanso.1986.45
    JOURNAL FREE ACCESS
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    The stability of CaCl2-and FeCl3-graphite intercalation compounds (GICs) was examined. CuCl2-and FeCl3-GICs were prepared from Grafoil strips by the“two-bulb” or “mixed” methods. The composition and the stage structure of the resultant GICs were determined by the weight-increase and X-ray diffraction measurements.
    The stability of the GICs was examined by the two methods. Firstly, the GICs prepared were kept in the air at room temperature, and their degradation with time was followed up to 35 days by X-ray diffraction and electrical resistivity measurements. It was found that CuCl2-GICs were rather stable and only a small change was found in both the resistivity and X-ray diffraction pattern, while a considerable degradation was observed on FeC13-GICs in a few days. The tests for the thermal stability of the GICs also showed the similar tendency. Thedegradation temperatures in the air and in the nitrogen atmosphere were determined as 310°C and 330°C for CuCl2-GIC (1st stage), and about 300°C in both cases for FeCl3-GIC (1st stage), respectively.
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  • Studies on Oxidation Process of Spun Pitch by Means of Electron Spin Resonance
    Tetsuro Yokono, Kazuyuki Murakami, Yuzo Sanada
    1986 Volume 1986 Issue 125 Pages 53-56
    Published: April 25, 1986
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.7209/tanso.1986.53
    JOURNAL FREE ACCESS
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    Oxidation process of spun pitch has been studied by means of electron spin resonance method. Spin concentration of spun pitch increases with increase of oxidation time at 473-553K, reaches a maximum and then decreases with stabilization of it. ESR is a technique applicable to monitor the stabilization reaction of spun pitch.
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  • Surface Treatment of Bulk meso-carbon by Oxidizing and Non-oxidizing Gas Plasma
    Kunio Esumi, Masaaki Sugiura, Toshiaki Mori, Kenjiro Meguro, Hidemasa ...
    1986 Volume 1986 Issue 125 Pages 57-61
    Published: April 25, 1986
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.7209/tanso.1986.57
    JOURNAL FREE ACCESS
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    The surface treatment of bulk meso-carbons using oxidizing (oxygen) and nonoxidizing gas (nitrogen, ammonia) plasma was carried out .As a result, acidic groups on the surfaces were formed by the oxidizing plasma and basic groups by the non -oxidizing plasma, resulting in the enhancement of wettability of the bulk meso-carbons into an aqueous solution.Furthermore, the plasma treatment was much more effective on the wettability for the bulk meso-carbon prepared from petroleum pitch than the bulk me so-carbon from coal-tar pitch.
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  • Microstructure of Carbon Fiber/Carbon Composites Carbonized under Pressure with Coal-Tar-Pitch as Matrix Precursor
    Shiushichi Kimura, Eiichi Yasuda, Kouichi Yasuda, Yasuhiro Tanabe, Kaz ...
    1986 Volume 1986 Issue 125 Pages 62-68
    Published: April 25, 1986
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.7209/tanso.1986.62
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    The coal-tar pitch was fractionated by the difference in solubility to organic solvents.Microstructures of carbons derived from fractionated pitchs themselves and those in CF/C Composites were investigated by optical microscopy. The microstructures of the carbon derived from BS pitch, BI/PS pitch, and PI pitch are flow, fine mosaic, and isotropic, respectively. The effect of carbon fiber on reduction of the anisotropic region of the matrix carbon apprears in some fractionated pitchs.This is related to the viscosity.Microstructure of the composite can be controlled by the mixture of fractionated pitches.
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  • Brittle Fracture Criterion Under Multiaxial Stresses
    Hideo Awaji
    1986 Volume 1986 Issue 125 Pages 69-76
    Published: April 25, 1986
    Released on J-STAGE: June 28, 2010
    DOIhttps://doi.org/10.7209/tanso.1986.69
    JOURNAL FREE ACCESS
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    Criteria of macroscopic brittle fracture under multiaxial stresses are discussed to provide for a new design criterion of a nuclear graphite which is expected to be used for a High Temperature Gas Cooled Reactor.Under the stress state in which tensile stresses are predominant, the maximum principal stress theory is applicable for the brittle fracture.Under the stress state in which compressive stresses are predominant, there may be two fracture modes for the brittle materials, namely, the slipping fracture and the mode II fracture.The maximum shear stress criterion is available for the slipping fracture mode.For the mode II fracture, we propose the following mode II fracture criterion,
    τmax=τ0+ξ (σ1+σ3)
    where, τmax isthe shear strength of the material, τ0 is the shear stress at the beginning of the crack propagation, σ1 and σ3 are the maximum and minimum principal stresses. ξis a coefficient referred to restraint for cracks.The above equation is the same in form as the Coulomb-Mohr criterion, but the meanings included in it are quite different.
    Also we discuss the statistical criterion for the brittle fracture under multiaxial stresses.
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