炭素

フッ化黒鉛の結晶構造におよぼす反応条件の影響

渡辺信淳, 喜田康

1976 年 1976 巻 84 号 p. 2-6
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.2

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The effect has been studied of reaction conditions such as temperature, fluorine pressure and time on the crystal structure of graphite fluoride by differential thermal analysis (DTA) method and X-ray diffractmetry. The natural graphite from Madagascar ores ground to 200-250 mesh was used for the substrate of fluorination. The experiments have been carried out under fluorine pressure 100 to 400 mmHg at temperatures in the range 500-600°C. Since there was found a close correlation among β₀₀₁, d₁₀₀ and d₀₀₁, the crystallinity of graphite fluoride was evaluated by d₀₀₁ values.
Since the result of DTA agreed well with that of X-ray diffractmetry, the thermal property of graphite fluoride could be correlated to its crystal structure. Until the sample was completely fluorinated, the crystallinity of graphite fluoride increased with increasing temperature and decreasing fluorine pressure. After the complete fluorination (C: F=1: 1), the crystallinity of graphite fluoride increased linearly with the logarithm of time, the slope of which was dependent on the temperature but not on fluorine pressure. The lattice strain of carbon layer accelerated the crystallization, which took longer time than that required for the formation of graphite fluoride.

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セルロースカーボンとCVDカーボンとの複合体

S. Marinkovic, P.W. Whang, A. Navarrete, P.L. Walker

1976 年 1976 巻 84 号 p. 7-13
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.7

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低圧でセルローズ粉末をモールド成形して800℃ に炭化させた材料に, プロピレンを700℃ で浸透, CVD処理 (Chemical Vapor Deposition) して作った複合体を1000～2400℃ 間の種々の温度で熱処理した。浸透速度はその度の開いた多孔度に支配された。曲げ強さ, 弾性率, クヌープ硬度, 電気比抵抗は, 試料の見掛密度dと, Y=a・d^bという関係にあった。熱膨脹係数 (CTE), 耐摩耗性, 耐酸化性は浸透時間と共に増加し, 表面積は浸透初期に急に減少した。熱処理温度は, 試料の特性を大きく変化させたが, 処理温度上昇と共に単純増加又は減少することはなかった。比較のために, 最密のものとしてのglassy carbon製品を測定した結果, CTEや酸化速度は, この複合体の方が低く, 曲げ強さや比抵抗は相似, 弾性率, 耐摩耗性, 硬度はglassy carbonの方が大きかった。

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メソカーボン・マイクロビーズ添加法によるバインダーピッチの製造と性状

筒井博, 山田泰弘, 本田英昌

1976 年 1976 巻 84 号 p. 14-19
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.14

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Binder pitch for the production of carbon materials was prepared by adding meso-carbon microbeads (Type-M) to straight coal-tar pitch.
The straight coal-tar pitch containing 0-20 wt% Type-M microbeads was heat-treated at temperatures between 300 and 400°C. The amounts of fixed carbon (FC), benzene insolubles (BI) and quinoline insolubles (QI), and softening Point (SP) of the pitch were measured. Then, the capability in using the pitch as bmder for carbon materials was examined by measuring compressive strength of the carbon blocks prepared by using the pitch.
Values of FC, BI, QI and SP of the pitch increased linearly with increasing of additional amounts of Type-M microbeads and could be estimated from its additional amounts. The compressive strength of carbon blocks prepared from the mixture of the 35 wt% pitch with 65 wt% coke powder was measured. The compressive strength of carbon blocks had high values when the pitch containing 3-10 wt% Type-M microbeads were used, and these values were higher than those of the carbon blocks produced by using commercial binder pitch.
These results show that the characteristics of pitches can be controlled easily by additional amounts of meso-carbon microbeads and that the carbon blocks in which these pitches are used as a binder have high compressive strength.

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黒鉛の磁気抵抗のH²依存性からのずれと伝導パラメーターの評価

能登潔, 都竹卓郎

1976 年 1976 巻 84 号 p. 20-25
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.20

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The magnetoresistance (Δρ/ρ₀) of graphite is discussed into details with an emphasis on the magnetic field dependence systematically deviating from the so-called quadratic law. A two-band theory developed on the basis of the ellipsoidal approximation for the Fermi surfaces has yielded a success in the formulation ofΔρ/ρ₀ as a function not only of the field intensity (H) but of its azimuth with respect to the c-axis; which reveals that the deviation is an intrinsic nature of the majority carrier system of graphite, rather than a result of the presence of the low-mobility minority carriers. Therefore, the conduction parameters (carrier density and mobility) have to be consistently determined with such a non-quadratic H-dependence ofΔρ/ρ₀; appropriate methods for the evaluation are described in connection with the foregoing two-band theory, McClure's conductivity tensor analysis and modified Kohler's rule respectively.

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グラファイトの熱磁気効果測定について

Kiyoshi KAWAMURA, Hisashi OHSHIMA, Takuro TSUZUKU

1976 年 1976 巻 84 号 p. 26-28
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.26

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グラファイトの熱磁気効果測定の際, 磁場反転の操作が如何に必要であるかを, 測定例を示して指摘した。この操作は, フナノン・ドラッグ効果が顕著な40°K近辺において, 特に無視できない。これらを, 比較的良く知られている電流磁気効果の測定と対応させて述べた。

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炭素材料の機械的性質の測定

金順一, 宮内正行

1976 年 1976 巻 84 号 p. 29-36
発行日: 1976/02/10
公開日: 2010/06/28

DOIhttps://doi.org/10.7209/tanso.1976.29

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