The electronmicroscopic observation was made on industrial carbon electrodes. The specimen pieces, cutted out from the cylindrical electrodes (cf. Fig. 1), were embedded in methyl metacrylate resin. The surface of the specimen was polished with emery paper and buffing, and etched with perchloric acid aqueous solution. Replicas were made successively with methylcellulose and ethylcellulose. The ethylcellulose replica was shadowed with chromium on its positive side, and then carbon was evapolated on it. After dissolving the ethylcellulose, the carbon film replica was used for the observation. This procedure gave the best result. Typical electronmicrographs are shown in Fig. 5 and Fig. 7.
Plate-like grains are observed in every specimens, whose size is about 2 microns average, probably they are clusters made of minute single crystals. The grains are aligned themselves with their planes in parallel with each other, and to the axis of the cylinder. Thus, the face-1 is more flat than the face-3.

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Impervious graphite products have been excellent uses in chemical industries, but they are available hitherto only at temperature range up to 170°C, owing to the thermal limitation of impregnant resins.
We have investigated to manufacture impervious graphite materials for high temperature uses and succeeded in making graphite stock impervious at the temperature up to 1000°C. Divinylbenzene rich styrene type impregnants are used and the impregnated stocks are baked at such controled condition as fill the pores of graphite impervious with the pyrolysed resin, that is polymer carbon only.
These products will be useful not only in chemical industries more widely than they are today, but in nuclear industry as construction materials of high temperature reactor such as LMFR etc.

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