Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Kernforschungsanlage Julich

Forschungszentrum Julich Gmbh

Hubertus Nickel

Hartmut Luhleich

Francesco Dias

Peter Pflaum

Erno Gyarmati

Ashok K Gupta

Rudolf Munzer

Francisco J Dias

Aristides Naoumidis

Hermann Kreutz

Arno Schirbach

Aristides Nauomidis

Willem J Quadakkers

Rudiger Forthmann

Zdravka Zadgorska

Muwaffak Hamesch

Ferdinand Baumanns

Metallic bipolar plate for high-temperature fuel cells and method of

A sample is fed to an ICP-AES by applying suction to a mouth of the sample vessel extending into the central or inner capillary tube of the burner from an annular orifice or a plurality of spaced apart orifices. The amount of sample material is controlled by volume flow control or gas pressure control. The sample is in the form of a powder or vapor without dilution or entrainment of chemical contaminants.

Method of and apparatus for feeding a sample to a plasma of an

Porous silicon carbide bodies are obtained by starting with a powder of particle size falling within a single sieve mesh range fraction and consisting either entirely of carbon particles or a mixture of carbon and silicon carbide particles of the same mesh fraction is mixed or coated with 15 to 30% by weight of a binder, moulded to shape, warmed in the temperature range from 40.degree. to 200.degree. C. to vaporize volatile material and then coked at a temperature rising to 850.degree. C. Then it is siliconized by raising the temperature to the range from 1650.degree. to 1950.degree. C. with gaseous silicon or impregnated with silicon by dipping the body into a silicon melt and convert it to carbide, with the excess silicon thereafter being removed by vaporizing out or by boiling in lye. Sieve mesh fractions in the region of a few hundred .mu.m are preferred, and the density of the porous body after pressing but before siliconizing should lie in the neighborhood of 0.6 to 0.7 g/cm.sup.3.

Method of making porous silicon carbide bodies

A significant improvement of the silicon impregnation depth of a carbon precursor body in the siliconizing thereof to make a silicon carbide body is obtained, as well as an accelerated conversion into silicon carbide if activated carbon is used in whole or in part as the carbon powder component of the precursor body. The molding material is preferably 20 to 60% by weight of binder and 20 to 70% activated carbon. This molding material may also usefully contain 10 to 60% by weight of .alpha.-silicon carbide, which may be previously made by siliconizing carbon powder.

Method of producing silicon carbide bodies

In order to prevent a protective carbide layer on a graphitic molded arti from splitting off under thermal stress, an external carbide layer is provided on a graphitic molded article having a graded content of silicon or zirconium (in the carbide state) that increases from near zero at the interior boundary of the layer to about 50 atomic percent at the exterior. Such a layer is produced either by dipping the graphitic molded article into melted silicon, dipping it into a succession of suspensions of carbon and either silicon or zirconium, with a greater silicon or zirconium content in each successive dip, the suspensions also including a binder resin, or by applying layers of a paste of carbon and either silicon or zirconium, also with some resin, each successive layer having a higher silicon or zirconium content. In the case of the successive dipping into suspensions, the article is dried after each dip and then heated to harden the binder, and in the case of application of successive paste layers, the binder is likewise hardened each time. In each case, the treatment terminates with heating to a coking temperature, followed by a rapid rise of temperature to a value at which silicon carbide or zirconium carbide will be formed, followed by cooling to room temperature.

Graphitic molded article with corrosion-resistant surface layer stable

In order to prevent a protective carbide layer on a graphitic molded article from splitting off under thermal stress, an external carbide layer is provided on a graphitic molded article having a graded content of silicon or zirconium (in the carbide state) that increases from near zero at the interior boundary of the layer to about 50 atomic percent at the exterior. Such a layer is produced either by dipping the graphitic molded article into melted silicon, dipping it into a succession of suspensions of carbon and either silicon or zirconium, with a greater silicon or zirconium content in each successive dip, the suspensions also including a binder resin, or by applying layers of a paste of carbon and either silicon or zirconium, also with some resin, each successive layer having a higher silicon or zirconium content. In the case of the successive dipping into suspensions, the article is dried after each dip and then heated to harden the binder, and in the case of application of successive paste layers, the binder is likewise hardened each time. In each case, the treatment terminates with heating to a coking temperature, followed by a rapid rise of temperature to a value at which silicon carbide or zirconium carbide will be formed, followed by cooling to room temperature.

Making temperature-stable protectively coated graphite molded body

A portion of the feed gas is supplied in a pulsating fashion to a fluidized ed reactor containing the articles to be coated mixed with fluidizing particles. The pulse frequency is between 1 and 10 Hz. A continuous flow of a portion of the total gas supply at a rate insufficient to produce turbulence in the bed is provided to facilitate control of the pulsing frequency and reduce the energy necessary for the pulsating gas stream. The gases fed to the reactor are a coating gas and a carrier gas, the flow containing the coating gas including a portion of the carrier gas. Either the pulsed flow or the continuous flow may consist entirely of carrier gas. The fluidizing particles are preferably of the same material as the articles to be coated and are typically of a grain size between 2 and 3 mm.

Pyrolytic gas method of coating graphitic or ceramic articles with solids

Shaped graphitic or graphite-like carbonaceous bodies are produced by forming binder-coated particles of a carbonaceous filler in a slurry, shaping the slurry or paste of the particles to the desired configuration, drying and cokefying the shaped body. The system is suitable for the production of graphitic structures for use in high-temperature gas-cooled nuclear reactors, as casting molds and the like. The present invention starts with the assumption that binder-coated filler particles are available, the particles having been coated uniformly (e.g. as described in our application Ser. No. 267,480).

Method of making shaped carbonaceous bodies

Shaped graphitic or graphite-like carbonaceous bodies are produced by forming binder-coated particles of a carbonaceous filler in a slurry, shaping the slurry or paste of the particles to the desired configuration, drying and cokefying the shaped body. The system is suitable for the production of graphitic structures for use in high-temperature gas-cooled nuclear reactors, as casting molds and the like. The present invention starts with the assumption that binder-coated filler particles are available, the particles having been coated uniformly (e.g. as described in U.S. Pat. No. 4,009,143.

Carbonaceous material such as carbon powder is coated with a carbonizable nder in a continuous process in which the carbon particles and the binder, preferably together with a solvent, are introduced continuously into a vessel in which a continuous stream of a liquid vehicle in which the binder is insoluble is likewise introduced. The coated particles are then separated from the liquid phase by decantation or filtration.

Process for producing carbonaceous substances for use in

Fissionable fuels and/or fertile breeder materials for nuclear reactors crised of fissionable or potentially fissionable materials having evenly distributed throughout certain metal oxides, such as aluminum oxide and niobium oxide, exhibiting the capacity to retain products formed by nuclear fission as stable, nonvolatible compounds in the nuclear material. The fuel element is combined with an effective amount of oxide that is relatively nonvolatile, has a low neutron-capture cross-section and forms such stable, nonvolatile compounds with the solid products resulting from nuclear fission.

Method of making fissionable-fuel and fertile breeder materials for

A method of cross-linking and hardening with the aid of heat a porous for body of a synthetic graphite or similar material, especially a fine granular graphite, which is bonded by means of a synthetic resin binding agent on a novolak basis. The thus formed porous body is a temperature of from 100.degree.C to 200.degree.C gassed by a quantity of formaldehyde which quantity depends on the predetermined extent of cross-linking of the formed body, while the formaldehyde is caused to pass from the outer surface of the formed body into the interior thereof.

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Julich, Germany

Hubertus Nickel