Abstract: A crucible protection sheet is provided that can prevent damages to an inner crucible, hinder an outer crucible from silicon-carbidization, and transmit heat from the outer crucible to the inner crucible uniformly. In a crucible having an inner crucible 2 and an outer crucible 3, the crucible protection sheet is arranged between the two crucibles and is made of expanded graphite. The planar thermal conductivity is 120 W/(m·K) or higher, the gas permeability is less than 1.0×10?4 cm2/s, and the compression ratio is 20% or higher when the sheet is compressed in a thickness direction at a pressure of 34.3 MPa. Since the compression ratio is high, the effect of preventing breakage is great when inserting the inner crucible, improving workability and preventing the inner crucible from tilting inside the outer crucible.

Abstract: The present invention provides a carbon material and a machining method for the same in which a dust control agent such as paraffin, wax, and oil is impregnated into the inside of a carbon material before being machined so that dust is hardly generated from the carbon material itself when machining the carbon material impregnated with the dust control agent with a machine tool.

Abstract: An object of the invention is to provide a heat generator having an expanded graphite sheet which is excellent in mechanical strength and flexibility and which is satisfactory in electrical properties as required by a heater, and especially a heat generator which is usable as a heater for the seats of vehicles, and the object of the invention can be achieved by forming an electrical insulating reinforcement on at least one surface of the expanded graphite sheet.

Abstract: An object of the invention is to provide a heat generator having an expanded graphite sheet which is excellent in mechanical strength and flexibility and which is satisfactory in electrical properties as required by a heater, and especially a heat generator which is usable as a heater for the seats of vehicles, and the object of the invention can be achieved by forming an electrical insulating reinforcement on at least one surface of the expanded graphite sheet.

Abstract: A mixture comprising 40-80 mass % of expanded graphite, 5-25 mass % of heat-resistant reinforcing fiber and 10-40 mass % of heat-resistant binder is formed into a sheet form and then cured to form a sheet. The sheet is formed into a drag washer by punching, for application to a fishing reel's drag washer.

Abstract: A mixture comprising 40-80 mass % of expanded graphite, 5-25 mass % of heat-resistant reinforcing fiber and 10-40 mass % of heat-resistant binder is formed into a sheet form and then cured to form a sheet. The sheet is formed into a drag washer by punching, for application to a fishing reel's drag washer.

Abstract: A high-purity carbon fiber reinforced carbon composite formed by a process which entails graphitizing a molded member packed with carbon fibers, which fibers are subjected to a purification process under halogen gas prior to being graphitized and prior to being packed with a matrix of carbon material, and the matrix of carbon material, the carbon fiber reinforced carbon composite having an impurities content of not more than 30 ppm in ash content and satisfies either or both of the following conditions for impurities: (1) V is not more than 0.12 ppm by ICP-OES; and (2) Fe is not more than 0.10 ppm by ICP-OES.

Abstract: Since the dense and high purity pyrolytic-carbon-coated layer is formed with a thickness of 10-100 &mgr;m on the surface of the C/C composite, even when metallic impurities of the inside C/C composite are 5-100 ppm in ash content, similar effects to those of a known crucible made of the C/C composite whose inside was subjected to high purification can be produced to achieve full applicability to the structural elements of the CZ apparatus. Also, since the process time required or the C/C composite itself to be subjected to the high purification can be shortened, the effect of reducing the manufacturing costs considerably can be obtained.

Abstract: A carbon electrode is disclosed comprising a porous carbon block and having a flexural strength of at least 50 MPa and exhibiting, on a linear sweep voltammogram obtained by subjecting the carbon electrode to potential sweep in concentrated sulfuric acid at 25.degree. C., a peak having a maximum current density at a potential of at level 1.2 V. This carbon electrode is substantially free from the danger of destruction and the danger of local breakage and partial coming-off and can advantageously be used as an anode not only for stably conducting the electrolysis of an HF-containing molten salt but also for producing a desired electrolysis product with high purity.

Abstract: A refractory heat-insulating graphite sheet material characterized in that the material comprises a graphite sheet.

Abstract: A shaped article of a carbonaceous material characterized in that the carbonaceous material is impregnated with a borosilicate glass comprising 25 to 50 wt. % of SiO.sub.2 and 20 to 45 wt. % of B.sub.2 O.sub.3 as effective components.

Abstract: A method of producing a graphite intercalation compound by intercalating a substance into graphite between layers thereof, characterized in that graphite particles are subjected to electrolysis in an electrolytic solution containing a substance capable of intruding into the interlayer spacings of the graphite while applying a load to the graphite particles in at least one direction to press all the graphite particles to the surface of an anode. According to the method, there can be obtained the desired porduct having a uniform and high quality.

Abstract: Novel metal salts of boric acid esters of saccharides have been found to be extremely useful for imparting a high oxidation-resistance to carbonaceous materials. The metal salts of the boric acid esters according to the present invention are water-soluble and can be easily formulated into aqueous solutions thereof. Therefore, the treatment of carbonaceous materials can be easily, simply done using an aqueous solution of the present metal salt of the boric acid ester.

Abstract: Wet graphite particles obtained by subjecting graphite particles to oxidizing treatment with nitric acid of comparatively low concentration and a permanganic acid salt and impregnating the treated graphite particles with a specific antioxidant comprising a metal salt of a boric acid ester of a saccharide, are heated to form expanded graphite masses, which are then compressed together to obtain a flexible graphite product. The thus obtained flexible graphite product is not only excellent in heat resistance and chemical inertness but also free of contamination with sulfur and chlorine, and is very useful in various applications.