| 摘要 |
PURPOSE:To produce a molded carbon material having low coefficient of thermal expansion and excellent thermal shock resistance while suppressing puffing by selecting needle-like coke showing specific magneto-resistance anisotropy, blending the coke with a binder, molding, burning and graphitizing. CONSTITUTION:Needle-like coke having <=0.35gammaTL and <=0.8gammaT ratios of magneto- resistant anisotropy defined by formula I and formula II is selected after heat treatment at 2,700 deg.C. Then the needle-like coke is blended with a binder, molded, burnt and graphitized to give a molded carbon material. An electric current is sent to the needle-like coke in the flow direction of fibrous structure, a magnetic field with a fixed magnitude is impressed in various directions, magneto resistance is measured and impression direction of the magnetic field showing the maximum magneto resistance is designated as the max direction. A direction close to the direction of electric current between impression direction of magnetic field wherein the maximum value of magneto resistance is measured and impression direction of magnetic field wherein the minimum value of magneto resistance is measured among directions in a plane perpendicular to the max direction is designated as TLmin direction and the other is designated as Tmin direction. When a magnetic field is impressed in the TLmin direction, the Tmin direction and the max direction, values shown by formula III, formula IV and formula V are measured values of magneto resistance. |
