Abstract: The present invention provides a graphite layer material to be used as an electrode material which exhibits excellent cell characteristics when used for a secondary cell. The graphite layer material of the present invention comprises highly oriented graphite layers of which a direction of crystalline orientation is adjusted to a planar direction, and an intercalant being inserted between the graphite layers.

Abstract: A process for producing a graphite block from a plurality of graphitizable polymer films or a plurality of carbonaceous films separately obtained from graphitizable polymer films is described. The method comprises superposing the plurality of the graphitizable polymer films or the plurality of the carbonaceous films, and thermally treating the plurality of the graphitizable polymer films or the plurality of the carbonaceous films in a substantially compression pressure-free condition when the treating temperature is in the thermal carbonization temperature range and the graphitization temperature range and under compression pressures in temperature ranges between the thermal carbonization temperature and the graphitization temperature ranges and over the graphitization temperature range. The compression pressure over the graphitization temperature range should be higher than that in the range between the thermal carbonization and graphitization temperature ranges.

Abstract: A process for making an artificial graphite film from a graphitizable polymer is described. In the process, a starting polymer film having a defined thickness is thermally treated at a temperature of not lower than 2400.degree. C. in an inert gas to graphitize the film, and rolled to obtain a graphite film. The graphite film has good flexibility and elasticity with relatively smooth surfaces.

Abstract: Graphite blocks are produced by a process wherein one or plural polymer films having a thickness of from 1 to 400 .mu.m and selected from aromatic polyimides, aromatic polyamides and polyoxadiazoles are heat treated to obtain carbonaceous films. A plurality of the carbonaceous films are hot pressure under certain conditions to obtain thick graphite blocks. The blocks have a remarkably improved rocking characteristic and are useful as radiation optical elements such as X-ray or neutron ray monochromators or filters. The blocks may be curved to obtain bent-type graphite articles.

Abstract: A method for making a graphite sheet or block with a desired thickness which comprises hot pressing at least two films of a polymer selected from a polyoxadiazole, an aromatic polyamide and an aromatic polyimide at a pressure not lower than 4 kg/cm.sup.2 at temperatures not lower than 2200.degree. C. Prior to the hot pressing, the at least two films may be thermally treated at temperatures of not lower than 2200.degree. C. and subsequently hot pressed at a pressure of not lower than 4 kg/cm.sup.2 at a temperature of not lower than 2000.degree. C. when the at least two films are made of the polyoxadiazole or aromatic polyamide or at a temperature of not lower than 1600.degree. C. when the at least two films are made of the aromatic polyimide.