The adsorption and desorption isotherms of nitrogen and carbon dioxide gases were measured at different temperatures on 22 activated carbons, which were derived from various precursors with various morphologies. All samples, except two from phenol resin spheres (APT and APF), showed perfectly reversible adsorption and desorption isotherms, and gave an unique curve of Polanyi potential on CO₂ gas. On these samples the BET surface area measured by N₂ coincided with that by CO₂. On the sample APT, however, irreversible adsorption was observed on CO₂ at temperatures between 0 and-72°C and N2 only at-196°C. This suggests the trapping of these gas molecules. Its Polanyi plots for CO₂ could not be appoximated by an unique curve. The sample APF showed irreversible adsorption only on N₂ gas at-196°C. On these samples the BET surface area measured by CO₂ was much higher than that by N₂.

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A crack propagation along the radial direction of the cylindrical graphite terminal has been observed in industrial graphitization furnaces. This crack often occurs with a concentrically circular shape at about 30-40cm from the high temperature end. The thermal stress of the terminal was analyzed by using the finite element method, taking account of the temperature distribution in the terminal as well as the temperature dependencies of the thermal and mechanical properties. The fracture seems to occur just before the end of the electrically charging period, when the temperature of the graphitization furnace reaches the maximum value by joule heating. A small temperature difference in the radial direction by radiation from the surface of the terminal in addition to the high thermal expansion coefficient at high temperature enhances the maximum hoop stress and consequently induce the fracture.

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Surface modification of PAN based carbon fiber (CF) by photo-oxygenation was investigated to give high adhesion between CF and cement matrix to CF/cement composites (CFRC). Photooxygenation was carried out by radiating ultraviolet rays (120w, 184.9nm, 253.7nm) onto CF paper under ozone stream (normal pressure). CF surface was remarkably modified to hydrophobic by photo-oxygenation treatment. CFRC plates (thickness: 6mm) were prepared by laminating 12 sheets of CF paper preimpregnated with portland cement paste (W/C=40%), and cured in water (14 days). These CFRC plates prepared from CF paper pretreated by photo-oxygenation treatment, exhibited higher flexural strength compared with those from CF paper without photo-oxygenation treatment.
The mechanical properties of CFRC prepared from photo-oxygenated CF paper were influenced by the temperature and time of treatment. The most effective condition of photo-oxygenation treatment on CF paper was the one at 150°C for 28min. The flexural strength (72MPa) of CFRC plate prepared with this photo-oxygenation on CF paper, was the largest of all.

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In order to investigate the roles of oxygen, heat and distillation in air-blowing reaction, the polymerization of a coal tar pitch in oxygen reaction, heat-treated reaction and distillation were studied by observing the molecular structures of the material pitches and product pitches with NMR and ESR measurements. It was found that the oxygen reaction was most effective to raise the softening point of the product pitches. This can be mainly ascribed to the polymerization with biphenyl-type bonding and the suppression of the pyrolysis of material in the reaction. On the other hand, the heattreated reaction without oxygen proceeded to the formation of larger peri-condensed aromatics which gave rise to anisotropy of pitches. The distillated pitch increased methylenic bonding between two aromatics in molecule which gave lower molecular orientation.

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Compositionally different five borosilicate glasses were impregnated into isotropic graphite material, IG11N, to get rid of pores over 2μm. This has allowed the material of 1-2 orders of magnitude in the decrease of carbon oxidation rate. The oxidation resistivity are improved by glass film covering on carbon block. Temperature region with the particularly low rate constant depends on the SiO₂ content in the glass. The higher SiO₂ content gives rise to the higher temperature region. Mechanical strength at room temperature has been extremely improved from 37MPa to 70-78 MPa for bending strength and from 9.2GPa to 16.7-17.4GPa for elastic modulus. Retention of electrical conductivity has shown that few crack propagation or oxidation suffered from the glass impregnation process.

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A plasma treating apparatus was newly constructed to modify the surface of carbon fiber (CF) continuously. This apparatus contains a pair of anode rings and a pair of cathode rings. A CF yarn was set along the central axis of the anodes. When a voltage of 400V was applied between the electrodes, plasma was generated around the CF yarn. Oxygen plasma treatment was carried out for two types of PAN-based CF (high strength type and high modulus type). Modification degree of the CF surface was estimated by measuring its wetting force by a dynamic wettability tester. This treatment modified the surface of high strength type CF to be hydrophilic, increasing its wettability remarkably, while no modification was caused on the surface of high modulus type CF.

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The friction and wear properties of a graphitized carbon material (disk) were investigated in air at temperatures from room temperature to 500°C. Thepin-on-disk type friction and wear testing machine was used with five different carbons as the pin materials.
The coefficient of friction (μ) and the specific wear rate (Ws) of the disk were measured. When graphitized carbon materials were used as thepin, p was low at all temperatures. On the other hand, when non-graphitized carbon materials were used as the pin, p became higher with temperature. The Ws-values of the disk were smaller at all temperatures when graphitized carbon materials were used as the pin. It is concluded that the graphitized carbon material (disk) shows better friction and wear properties when graphitized carbon materials rather than non-grapitized carbon materials were used as the pin.

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