Abstract:
A dimensionally stable combustion synthesis product of a composition containing at least 20 % by weight of a particulate combustible material; at least 15 % by weight of a particulate filler material capable of providing desired mechanical and electrical properties; and up to 35 % by weight of a particulate inorganic binder having a melting point lower than the combustion synthesis temperature. Electrodes suitable for electrochemical processing are a preferred product form, particularly electrodes for use in the electrowinning of aluminum from its oxide.
Abstract:
Combustion synthesis process using microwave energy. The process uses microwave energy to ignite at least two reactants which are capable of reacting exothermically to produce a reaction product. In accordance with one embodiment of the invention, combustion of the reactants is also controlled using microwave energy.
Abstract:
A method of obtaining complex oxides based on at least two metals of groups I to VI of the periodic system comprises mixing a burning and an oxide component and an oxidizing agent and thermal processing of the prepared mix until the desired product is obtained. The components are mixed in a ratio resulting in a final product of the desired stoichiometric relationship composition. The thermal processing is carried out in a regime of directed burning by means of self-propagating high-temperature synthesis in the oxygen or in an oxygen-containing gaseous medium. The invention may be used, for example, in the electrotechnical industry.
Abstract:
A method for the in-situ precipitation of second phase materials, such as ceramic or intermetallic particles, in a metallic matrix. By means of the Direct Addition Process, metal-second phase composites having highly superior properties may be obtained. Compacts of second phase-forming constituents and solvent metal are directly added to a molten metal bath to precipitate the second phase in-situ. Exemplary materials include titanium diboride or titanium carbide in an aluminum matrix.
Abstract:
Formation of a refractory repair mass, in particular on an alumina-containing surface which is to be exposed to heavy duties, employs a powder mixture comprising alumina and, by weight, at least 5 % of a metallic combustilbe which is at least 30 % aluminium, and 3 to 10 % of an absorbency-reducing agent. A ceramic welding technique is used, in which the powder mixture is projected in gaseous oxygen against the surface to be repaired such that reaction between the combustible particles and oxygen occurs against the surface, thereby releasing the heat of reaction against the surface to form the repair mass.
Abstract:
A process is provided producing a crystalline siliceous refractory mass by projecting solid refractory particles, solid silicon particles and gaseous oxygen against a surface in such a way that reaction between the silicon particles and gaseous oxygen occurs against the surface, thereby releasing the heat of reaction against the surface so that a coherent refractory mass comprising cristobalite is formed, wherein the solid refractory particles comprise silica in the form of vitreous silica and in that the surface against which they are projected is at a temperature of a least 1000 DEG C. The process can be used for in situ repair of high temperature furnaces such as glassmaking furnaces or for the manufacture of high quality refractory bricks.
Abstract:
The invention concerns the use of a reactive refractory mortar which is self-extinguishing beyond a predetermined penetration depth. The mortar consists of a mixture of 11 to 17 dry wt % aluminium powder, 18 to 31 dry wt % iron oxide, 8 to 18 dry wt % magnesium sulphate dissolved in water and 44 to 60 dry wt % magnesium oxide. The mortar is used for pointing refractory kiln linings consisting of refractory bricks, in particular for rotary kilns.
Abstract:
Electrical heating elements operable at high temperatures for long periods are produced by a method involving micropyretic synthesis. Compositions subjected to micropyretic synthesis comprise a powdery mass of electrically conductive and semiconductive material, a reactive system, a grain growth inhibitor and a plasticizer or extrusion agent.
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 comprising a first support means having a first and a second surface, said first surface being exposed directly to the atmosphere; 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, said heating element being connected to said second surface of said terminal, and not being in direct contact with said first support means so as to cushion said heating element from forces acting upon said first support means; and said first surface of said terminal being closer to said first support means than said heating element, and adapted to absorb some of the forces acting upon said first support means, so as to further cushion said heating elements.
Abstract:
A carbon containing material for use in particular as an anode of electrolytic cells for the production of aluminium by the electrolysis of alumina in a cryolite-based electrolyte, consists substantially of a mixture of one or more particulate carbonaceous material(s) with a binder based on compounds of aluminium with carbon, oxygen and/or nitrogen, such as aluminium carbide or aluminium oxycarbide, or such compounds mixed with aluminium. This binder is obtained by mixing the particulate carbonaceous material(s) with particulate aluminium and with at least one compound of aluminium, lithium, cerium, calcium and sodium in a liquid carrier, and heat treating to form the binder. The liquid carrier may comprise a binding agent selected from methyl cellulose, polyvinyl alcohol and colloidal suspensions, in particular colloidal alumina.