Abstract: Disclosed herein is an electrode substrate for fuel cells comprising two porous, carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which are provided near the center of the thickness in said layer, and a gas impermeable, carbonaceous separator, interposed between said layers and having a number of elongated holes for flowing coolant which are provided near the center of the thickness in the separator. The porous layer is either a uniformly porous, carbonaceous monolayer, or has a two-layer structure comprising a more porous layer, a less porous layer and elongated holes for feeding reactant gases provided between said more porous layer and said less porous layer, the less porous layer having a bulk density larger than that of the more porous layer. There are also provided according to the invention processes for preparing such an electrode substrate for fuel cells.

Abstract: An electrode substrate for fuel cells with a three-layer separator and two porous single or double carbonaceous layers and processes for preparing the same. The separator includes a carbon plate and two flexible graphite sheets. The porous layer has a number of elongated holes for feeding reactant gases into a fuel cell. The elongated holes are provided near the center of the thickness in the porous single layer or in the interface between the porous double layer. The electrode substrate exhibits improved properties, such as mechanical strength, thermal and electric resistances and the like, as a fuel cell electrode substrate.

Abstract: Disclosed herein are a carbonaceous composite product produced by joining carbonaceous materials together by melt-adhesion of a tetrafluoroethylene resin or a tetrafluoroethylene resin mixed with a highly electroconductive carbon black interposed between the carbonaceous materials, a composite electrode substrate for a fuel cell comprising the carbonaceous composite product and the process for producing the same.

Abstract: Disclosed herein is a carbon product comprising at least two carbonaceous materials and one flexible graphite sheet interposed between said two carbonaceous materials, said two carbonaceous materials and said flexible graphite sheet having been joined together and integrated by calcination in an inert atmosphere as one carbon body, and the joining surface of at least one of said carbonaceous materials comprising both joining parts and non-joining parts which have an optional shape and are uniformly arranged on the joining surface, said carbon product as the electrode substrate of fuel cells, and a process for producing the same.

Abstract: Disclosed herein is an electrode substrate provided with a manifold, for a fuel cell, comprising (1) the two porous and carbonaceous electrodes respectively provided with the flow channels of a reactant gas and joined to both surfaces of a separator via a flexible graphite sheet, (2) the separator which has been extended beyond the electrode and (3) the manifold which comprises a gas-impermeable and compact carbon plate and is provided with the flow passage for supplying the reactant gas and joined to the thus extended part of the separator via a flexible graphite sheet and the whole composite materials have been formed into one body as carbon, and a process for producing the electrode substrate.

Abstract: Disclosed herein are an electrode substrate provided with peripheral sealers for a fuel cell, comprisingtwo porous and carbonaceous electrodes respectively provided with flow channels of the reactant gas, said electrodes being joined to the both surfaces of a separator via a flexible graphite sheet so that said flow channels in one of said electrodes are perpendicular to those in another said electrode and said separator having the extended part which extends beyond a periphery of said electrode which is parallel to said flow channels in said electrode andeach peripheral sealer on the side of said electrode parallel to said flow channels therein, which comprises a gas impermeable and compact carbon material, said peripheral sealer being joined to said extended part of said separator via a flexible graphite sheet,the whole composite materials being formed into one body as carbon by calcination thereof under a reduced pressure and/or in an inert atmosphere, and a process for producing the electrode substrate fo

Abstract: An abrasing apparatus including an annular barrel having an upper opening. The barrel is rotated around an exciting coil and is filled with magnetic abrasive powder which is arranged by magnetic flux generated by the exciting coil to form magnetic brush. A work is embedded into the magnetic brush. The work is rotated together with a spindle and the barrel is rotated so that the surface of the work is abrased by the magnetic brush. A bottom magnetic pole, a lateral magnetic pole and an upper magnetic pole are disposed in an inner periphery in the barrel in the proximity to the exciting coil and the strong magnetic brush is locally formed therein. The side portion of the work is located in the local magnetic brush, and the bottom, side and upper surfaces of the work are abrased like a mirror surface.

Abstract: Disclosed herein is a reinforced flexible graphite sheet uniformly containing a thermosetting resin prepared by impregnating a flexible graphite sheet with a liquid thermosetting resin having the carbonizing yield of more than 20% under a reduced pressure and thereafter, heat-setting the resin, an amount of the resin impregnated being in the range of 0.5 to 20% by weight based on the flexible graphite sheet.

Abstract: Disclosed herein are processes for preparing electrode substrate for fuel cells which has an integratedly press molded five-layer structure comprising a porous carbonaceous layer, a dense carbonaceous layer having a bulk density larger than the porous layer, a separator, a dense carbonaceous layer having a bulk density larger than the porous layer, and a porous carbonaceous layer, and which further comprises a number of elongated holes for feeding reactant gases into a fuel cell in the interface between the porous layer and the dense layer.

Abstract: Disclosed herein is an electrode substrate for fuel cells comprising two porous, carbonaceous layers, each having a number of elongated holes for feeding reactant gases into a fuel cell which are provided near the center of the thickness in said layer, and a gas impermeable, carbonaceous separator, interposed between said layers and having a number of elongated holes for flowing coolant which are provided near the center of the thickness in the separator. The porous layer is either a uniformly porous, carbonaceous monolayer, or has a two-layer structure comprising a more porous layer, a less porous layer and elongated holes for feeding reactant gases provided between said more porous layer and said less porous layer, the less porous layer having a bulk density larger than that of the more porous layer. There are also provided according to the invention processes for preparing such an electrode substrate for fuel cells.

Abstract: Disclosed herein is a process for producing a carbonaceous electrode substrate for use in fuel cells, comprising two layers of a porous carbonaceous layer and a compact carbonaceous layer or three layers of two porous carbonaceous layers and a compact carbonaceous layer disposed between the two porous carbonaceous layers, wherein the porous carbonaceous layer(s) has elongated holes located nearly in the central region of thickness thereof, characterized by using high polymeric substance as a material for forming said elongated holes.

Abstract: Disclosed herein is an electrode substrate for fuel cells which comprises a three-layer separator and two porous single or double carbonaceous layers. The separator comprises a carbon plate and two flexible graphite sheets. The porous layer has a number of elongated holes for feeding reactant gases into a fuel cell. The elongated holes are provided near the center of the thickness in the porous single layer or in the interface between the porous double layer. The electrode substrate of the present invention exhibits improved properties, such as mechanical strength, thermal and electric resistances and the like, as a fuel cell electrode substrate. The present invention provides processes for preparation of such an electrode substrate.

Abstract: Disclosed herein is an electrode substrate for fuel cells which has an integratedly press molded five-layer structure comprising a porous carbonaceous layer, a dense carbonaceous layer having a bulk density larger than the porous layer, a separator, a dense carbonaceous layer having a bulk density larger than the porous layer, and a porous carbonaceous layer, and which further comprises a number of elongated holes for feeding reactant gases into a fuel cell in the interface between the porous layer and the dense layer. The processes for preparing the electrode substrates are also provided according to the present invention.

Abstract: A carbonaceous multilayer electrode substrate for a fuel cell disclosed herein has elongated holes for feeding reactant gases to the fuel cell. The electrode substrate comprises at least one porous carbonaceous layer having such holes. An electrode substrate of the invention comprises such a porous layer and a dense layer capable of effecting a function as a separator sheet. An another substrate of the invention comprises a dense layer and two such porous layers on both surfaces of the dense layer. A still another substrate comprises an extended dense layer and two such porous layers on both surfaces of the dense layer.

Abstract: An electrode substrate for a fuel cell having a high porosity, a good mechanical strength and electroconductivity and a sharp distribution of pore radii is prepared by a process comprising mixing 30 to 50% by weight of carbon fiber, 20 to 50% by weight of a binder and 20 to 50% by weight of an organic granule, press-shaping the resultant mixture, curing the shaped product and calcinating the cured product.

Abstract: Disclosed herein are shaped articles of porous carbon comprising carbon fibers having a compression strength of higher than 50 kg/cm.sup.2 and a porosity of 50 to 80%, in which radii of not less than 60% of the pores are distributed in a range wherein the difference between the upper pore radius and the lower pore radius is 20 microns.

Abstract: A method for producing spherical particles of carbon and of activated carbon is described, in which a mixture of a pitch and a viscosity-reducing agent is melt-extruded into a form of string-like bodies, the thus obtained string-like bodies are broken into stick-like bodies of a length to diameter ratio of 1 to 5 and the stick-like bodies are thermally deformed utilizing hot water as a thermal medium into spherical particles. The spherical particles are then subjected to conventional extraction to remove the viscosity-reducing agent therefrom, and the thus obtained spherical particles of pitch are converted into spherical particles of carbon or of activated carbon.

Abstract: The present invention relates to a method for preparing carbon fibers from a pitch by melt-spinning the pitch, infusibilizing the pitch fibers with a mixture of air and a gaseous oxidizing agent in an infusibilizing furnace divided into at least two chambers arranged in series under the condition of a velocity of the circulation gas in a specified range and then carbonizing the thus treated pitch fibers into carbon fibers.

Abstract: Disclosed is a method for the thermal cracking of a heavy petroleum oil to produce a pitch with a high aromaticity having a high softening point, the ratio of H/C of about 0.4 to 1.1 and the fraction insoluble in n-heptane but soluble in quinoline of higher than 55% by weight and an oil mainly composed of aliphatic hydrocarbon by feeding the heavy petroleum oil into a reaction system and bringing it therein into contact with a gas which does not react with the heavy petroleum oil, of a temperature in the range of from 400.degree. C. to 2000.degree. C., which method is improved by using, as the reaction system, a plurality of reaction vessels arranged in series and having their interior temperatures successively lower by a fixed step in the direction of the transfer of the charge.

Abstract: The present invention relates to a method for preparing carbon fibers from a pitch by treating the pitch fibers spun from a pitch with a gaseous mixture of air and a gaseous oxidizing agent in an infusibilizing furnace divided into at least two chambers arranged in series and then carbonizing the thus treated pitch fibers into carbon fibers.