Abstract: A membrane support usable for separative procedures is disclosed. The support is a mechanically solid composite carbon-carbon material of limited thickness in the passage direction Z of a flow to be treated, which composite has a porous texture appropriate for the membrane, with a fibrous substrate and a porous carbon-containing matrix. To increase the permeability and reduce the roughness of the outer surface of the support to be brought into contact with the membrane, the fibrous substrate is a carbon fibre mat of carbon fibre segments contained in a plane perpendicular to the Z axis and randomly oriented in that plane. Optionally a fraction of the support to be in contact with the membrane contains an inert fine powder dispersion making it possible to adjust the diameter of the pores of the outer face of the support. Also disclosed is a process for the production of this membrane support and its use as a membrane support and as a filtering element without the addition of a membrane.

Abstract: The invention relates to an electrically conductive, polymer based material with electrical resistivity having a positive temperature coefficient. The material comprises a matrix of thermosetting polymer having conductive particles in the form of fibers distributed through the polymer. The polymer can be an epoxy resin, polyimide, unsaturated polyester, silicone, polyurethane or phenolic resin, and the fibers can be carbon fibers, carbon fibers coated with metal or metal alloy, graphite fibers, graphite fibers coated with metal or metal alloy, graphite intercalation compound fibers, metal fibers, ceramic fibers, or ceramic fibers coated with a metal or metal alloy.

Abstract: The invention relates to a support intended to receive a mineral membrane for separation procedures, and processes for the production thereof. The support is formed by a carbon-carbon composite material of small thickness, which is mechanically strong and which is of a porous texture suited to the mineral membrane. It is produced by adjusting the porous texture of a carbon-carbon material.

Abstract: The invention relates to a process for preparing mineral and in particular, carbon-containing membranes on a porous mineral support. According to the process, at least one layer of a stable emulsion of mineral particles in a solution containing a thermosetting resin is deposited on a permeable, porous, mineral support. The resin undergoes a polycondensation treatment followed by coking, and the coke formed insures the mechanical connection of the mineral particles both to one another and to the support. The membranes produced according to the invention can be used in separating processes, particularly in microfiltration and ultrafiltration.

Abstract: The invention concerns a process for the production of vapor-deposited carbon fibres wherein a gaseous or vaporized hydrocarbon which is entrained by a carrier gas is pyrolyzed on a substrate in a flow reactor at a temperature of between 950.degree. and 1300.degree. C. in two successive stages, a germination stage and a growth stage.The process comprises the following steps:preparing a gaseous mixture comprising from 50 to 90% and preferably from 85 to 65% by volume of hydrogen and/or helium and from 10 to 40% and preferably from 15 to 35% by volume of methane;circulating the mixture in the reactor over a substrate comprising from 10.sup.-8 to 10.sup.-4 g/cm.sup.2 of a catalyst selected from iron, nickel, cobalt and alloys thereof;initiating germination and growth of the carbon fibres in respect of length at a temperature t1 which is stabilized at between 950.degree. and 1050.degree. C.

Abstract: The present invention relates to insertion compounds with improved performances for electrochemical applications. They are characterized in that they are obtained from a graphite with a specific surface area of at least 100 m.sup.2 /g, and a granulometry at most equal to 4 .mu.m. The graphite oxide or the graphite-NiCl.sub.2 first stage obtained from such a graphite is used as constituting agent of the cathode of a lithium battery and it gives to same excellent characteristics. The graphite oxide performances may further be improved by preparing it by double oxidation of a graphite having any specific surface area and the granulometry is of the order of the .mu.m, as shown by FIG. 2 which represents the intensiostatic discharge curves of the lithium batteries the cathode of which contains the graphite oxide.

Abstract: The electrolysis cell, e.g. for use in the construction of an electrolyzer for the production of hydrogen on an industrial scale, comprises an alternate series of electrodes 1 to 7 and plane diaphragms 8 to 13, which are parallel and separated from one another by spaces 58 in which an electrolyte can circulate between inlets 16, 17 located on one face 14 of the cell and the outlets 18, 19 located on an opposite face 15 of the cell. The inlet and outlet faces 14, 15 of the cell are parallel to the electrodes and the inlets and outlets communicate with inlet and outlet channels 21 to 23 which extend perpendicular to the electrodes and are connected together by passages between the electrodes and diaphragms, alternate passages being connected to different inlets for different polarity electrolytes.

Abstract: A dual-textured graphite has been produced having an apparent coarse strongly bonded grained structure (the macrotexture) in which each coarse grain is formed from a number of strongly linked ultrafine grains (the microtexture). The dimensions of the coarse grains are from 0.4 to 6.0 m.m. while those of the ultrafine grains are below 0.050 m.m. The fine grains are linked by graphitized pore-containing carbon having pores of less than 2.mu. diameter. The coarse grains are also linked by graphitized pore-containing carbon having pores of from 5 to 20.mu. diameter. Further characteristics of the graphite are a coefficient of linear expansion of 4-6.times.10.sup.-6 /.degree. C., thermal conductivity of 0.20 cal/cm/.degree. C./sec., electrical resistivity of 1500-2000.mu. ohms/cm and anisotropy factor not exceeding 1.4. A process for producing such product from pitch and petroleum or coal tar coke is described.

Abstract: Dual pore-structured carbon and graphite consist essentially of a macroporous agglomeration of strongly bonded microporous grains of carbon or graphite the radii of the macropores therein being from substantially 10 to 350 .mu.m and those of the micropores from substantially 0.2 to 1.0 .mu.m, with the macropores being joined by intercommunicating channels which form a fluid permeable structure. Such carbon or graphite has a density of from 0.70 to 1.50 grams/cc., a permeability to gases of from 20 to 500 cm.sup.2 /sec/atmos and a porosity of from 30 to 50%. Such materials are produced by including in a mixture of tar or pitch and finely divided solid carbonaceous material in suitable proportions, a particulate eliminable non-carbon-forming material having a particle size of 10 to 350 .mu.

Abstract: This invention relates to the making of negatives intended for the production of bodies which contain cavities of predetermined shapes.The term "negative" signifies a disposable core member, for example as used in some molding techniques such as the lost wax process. The negative at least partly matches the cavities which latter form two independent systems of regularly distributed intersecting channels with the channels in any one same system intercommunicating via ducts which are themselves regularly distributed.

Abstract: This invention relates to the making of negatives intended for the production of bodies which contain cavities of predetermined shapes.The term "negative" signifies a disposable core member, for example as used in some molding techniques such as the lost wax process. The negative at least partly matches the cavities which latter form two independent systems of regularly distributed intersecting channels with the channels in any one same system intercommunicating via ducts which are themselves regularly distributed.

Abstract: This invention relates to the making of negatives intended for the production of bodies which contain cavities of predetermined shapes.The term "negative" signifies a disposable core member, for example as used in some molding techniques such as the lost wax process. The negative at least partly matches the cavities which latter form two independent systems of regularly distributed intersecting channels with the channels in any one same system intercommunicating via ducts which are themselves regularly distributed.

Abstract: The present invention relates to the field of fused-salt nuclear reactors and its object is the extraction of the gases produced in the course of operation of these reactors.The process according to the invention consists in placing into position a piece of material permeable for gases and impermeable for the used fused salts, for instance, a piece of graphite, in such a way that part of the surface of this piece is in contact with the circuit of the radioactive salts and another part connected to a gas suction device.The piece could also be scavenged in its mass by a flow of inert gas.Application is contemplated in reactors using a mixture of lithium fluoride, beryllium fluoride, and uranium and/or thorium fluoride.