Abstract: A method for optimizing the performance characteristics of a combustion synthesized ceramic or metal ceramic product, including the steps of initially applying sufficient current to the product so as to raise the temperature of the product to a minimum of 50% of the melting point in degrees Kelvin, of the lowest melting phase in the product and thereby densifying the product. A method for enhancing the adherence of a ceramic or metal ceramic electrical heating element to an electrical terminal, and for improving the electrical properties of the resulting product is included.

Abstract: A modular filter for removing particulate matter from gases or liquids is disclosed. The filter includes at least two porous ceramic or ceramic composite modules and a heater structure for regenerating the modules by heating which is integral with the modules. The regenerating structure may also be a ceramic structure. The filter modules may be manufactured using micropyretic synthesis and manufactured to have interconnected porosity. The filter may be used to remove particulates from the exhaust of engines such as engines of land and water vehicles.

Abstract: A carbon body, in particular a prebaked anode of an electrolytic cell for the production of aluminum by the electrolysis of alumina in a molten fluoride electrolyte, is treated over its surfaces to improve the resistance thereof to deterioration during operation of the cell by air and oxidizing gases released at the anode, by immersing the body in a treating liquid containing a soluble boron compound and at least one aluminum compound and/or at least one calcium compound as a powder, suspension or colloid or in solution, e.g. at 80.degree. to 120.degree. C. The same treatment can also be applied to a carbon mass forming a Soderberg anode and to cell sidewalls. The addition of the aluminum and/or calcium compound(s) increases strength and improves oxidation resistance compared to impregnation with boric acid alone.

Abstract: A method of producing a self-sustaining body of refractory boride from the group consisting of the borides of titanium, chromium, vanadium, zirconium, hafnium, niobium, tantalum, molybdenum and cerium. This body includes a refractory boride and a dried colloid from the group consisting of colloidal alumina, silica, yttria, ceria, thoria, magnesia, lithia, monoaluminium phosphate and cerium acetate and is obtained from a slurry of the refractory boride in one or more of said colloids by casting the slurry on a porous plaster layer, and drying the cast slurry by draining through the plaster, or by pressing/drying. Subsequently, the dried body is subjected to heat treatment to bond the refractory boride in the dried colloid. The bodies are useful as components of aluminium electrowinning cells.

Abstract: A component of an aluminum production cell, in particular a cathode or a cell lining of an electrolytic cell for the production of aluminum by the electrolysis of alumina in cryolite, having an aluminum-wettable refractory coating on a heat-stable baked carbon-containing body, is produced from a part-manufactured cell component which is a layered composite of two precursors. A precursor layer of the aluminum-wettable refractory coating contains at least one aluminum-wettable refractory material in particulate form, or a particulate micropyretic reaction mixture which, when ignited, reacts to form at least one aluminum-wettable refractory material, or a mixture thereof, and non-carbon fillers and binders. A non-baked or part-baked precursor of the heat-stable carbon-containing body comprises particulate carbon compacted with a heat-convertible binder which when subjected to heat treatment binds the particulate carbon into the heat-stable carbon-containing body of the fully-manufactured cell component.

Abstract: A cathode block of a cell for the electrowinning of aluminium comprises a carbon body having a hard and abrasion-resistant surface obtained by heating an applied layer of particulate refractory hard metal boride with a bonding material which when heated reacts with the refractory hard metal boride and with carbon. In particular a slurry of particulate refractory boride in colloidal alumina is dried and heated under an inert or a reducing atmosphere, formed by a bed of carbon powder, and reacted to form at least one stable compound between aluminium derived from colloidal alumina; boron and titanium derived from the titanium diboride; and carbon from the reducing atmosphere.

Abstract: Components of aluminium production cells made of composite materials comprising ordered aluminide compounds of at least one of nickel, iron and titanium, for use in particular as anodes and cathodes and cell linings in aluminium production cells containing a fluoride-based molten electrolyte containing dissolved alumina and cerium species, are produced by micropyretic reaction of a reaction mixture comprising compacted particulate reactants which react to produce the composite material. The reaction mixture is mixed with a cerium-based colloidal carrier, dried and compacted into a reaction body bonded by the cerium-based colloidal carrier, and the colloid-bonded reaction body is ignited to initiate the micropyretic reaction.

Abstract: Carbon or carbon-based cathodes and cell bottoms of electrolytic cells for the production of aluminium in particular by the electrolysis of alumina in a molten halide electrolyte such as cryolite, are treated to better resist intercalation of sodium in the cell operating conditions by impregnation and/or coating with colloidal alumina, ceria, cerium acetate, lithia, yttria, thoria, zirconia, magnesia or monoaluminium phosphate followed by drying and heat treatment.

Abstract: An electrolytic cell for electrolysis of alumina for the production of aluminum, comprising at least two cell components joined by a ramming paste consisting essentially of a compact mixture of one or more particulate carbonaceous material(s) with a non-carbonaceous non-polluting colloidal binder and optionally with one or more non-carbonaceous fillers, the binder being a suspension of one or more colloids, or being derived from one or more colloid precursors or colloid reagents optionally with one or more chelating agents.

Abstract: A modular membrane filter for gases liquid and particulate matter is disclosed, the filter comprising at least two porous ceramic or ceramic modules. A regenerative filter is also disclosed comprising a means for filtering; and a means for regenerating said means for filtering, said means for regenerating being integral with said filtering means.

Abstract: Carbon-containing components (1, 2, 5) of cells for the production of aluminium (8) by the electrolysis of alumina dissolved in a cryolite-based molten electrolyte (7) are protected from attack by liquid and/or gaseous components of the electrolyte (7) in the form of elements, ions or compounds, by a refractory boride coating (9, 10, 11) applied from a slurry composed of preformed particulate refractory boride in a colloidal carrier which is dried and heated to consolidate the coating.

Abstract: Electrical heating elements operable at high temperatures for long periods are produced by a method involving micropyretic synthesis. Compositions subjected to micropyretic synthesis comprises a powdery mass of electrically conductive and semiconductive material, a reactive system, a grain growth inhibitor and a plasticizer or extrusion agent.

Abstract: A porous membrane produced by preparing a slurry made from at least one micropyretic substance and at least one liquid carrier. The slurry is dried into a green form having a desired geometric configuration. Combustion of the green form produces the porous membrane.

Abstract: Components of electrolytic cells for the production of aluminum in particular by the electrolysis of alumina in a molten fluoride electrolyte, made of carbon or other microporous material which remains stable or may be consumed in the cell operating conditions, are conditioned to better resist in the cell operating conditions by impregnating them with colloidal ceria, cerium acetate, silica, alumina, lithia, yttria, thoria, zirconia, magnesia or monoaluminum phosphate containing ionic species of sodium, lithium, potassium, aluminum, calcium or ammonium, followed by drying and heat treatment.

Abstract: Electrical heating elements and related articles having oxidation resistance at high temperatures, produced by a method involving micropyretic synthesis. A composition subjected to micropyretic synthesis comprises a filler material, a reactive system capable of undergoing micropyretic synthesis, and (optionally) a plasticizer or extrusion agent. The method of preparation of articles includes slurry techniques, plastic extrusion, slip casting, or coating.

Abstract: A heating element assembly design and methods of densification of such designs are disclosed for radiant heating devices, specifically adapted to avoid breakage of or damage to the heating elements. The design includes a first support having a first and a second surface, the first surface being exposed directly to the atmosphere. The design further includes at least one ceramic or metal ceramic electrical terminal, having a first and a second surface; at least one ceramic or metal ceramic heating element with a diameter of up to 12 millimeters, the heating element being connected to the second surface of the terminal, and not being in direct contact with the first support so as to cushion the heating element from forces acting upon the first support. The first surface of the terminal being closer to the first support than the heating element, and adapted to absorb some of the forces acting upon the first support so as to further cushion the heating elements.

Abstract: An improvement process for producing a coated porous ceramic, ceramic composite or metal structure, wherein the impregnation step is carried out by (a) fluidizing said slurry with steam or heated water and spraying said shape with said fluidized slurry or (b) heating said slurry so as to reduce its viscosity and spraying said shape with said reduced viscosity slurry. Manufacture of a single component which functions both as a filter and as a heating element, is made possible by the process of the present invention.

Abstract: Carbon-containing components of cells for the production of aluminum by the electrolysis of alumina dissolved in a cryolite-based molten electrolyte are protected from erosion by non-chemical attack due to movement of liquid and/or gaseous components of the electrolyte, by a refractory boride coating applied from a slurry composed of pre-formed particulate refractory boride in a colloidal carrier which is dried and heated to consolidate the coating.

Abstract: Carbon-containing components of cells for the production of aluminum by the electrolysis of alumina dissolved in a cryolite-based molten electrolyte are protected from attack by liquid and/or gaseous components of the electrolyte in the form of elements, ions or compounds, by a treatment composition which consists essentially of a solution of one or more phosphates of aluminum. The treatment composition may alternatively consist essentially of one or more phosphates of aluminum, and one on more colloidal carriers.

Abstract: A carbonaceous, refractory or metal alloy substrate material coated with a refractory material, the refractory material including at least one of borides, silicides, nitrides, aluminides, carbides, phosphides, oxides, metal alloys, inter-metallic compounds and mixtures of one of titanium, chromium, zirconium, hafnium, vanadium, silicon, niobium, tantalum, nickel, molybdenum and iron and at least one refractory oxide of rare earth metals. An aluminum production cell including a component made up of a material coated with the coating described above is also disclosed.