Abstract: A method to produce an article of commerce comprising a self-supporting ceramic body by oxidation of a molten parent metal with a vapor-phase oxidant, includes applying to a surface of the parent metal a layer at least one dopant material therein. The layer is thin relative to the thickness of the ceramic body. Upon heating the parent metal to a molten state in the presence of the oxidant, e.g., air, an oxidation reaction product is formed on the molten metal which, because of the effect of the dopant material, migrates through the growing oxidation reaction product so as to be exposed to the oxidant to form additional oxidation reaction product to and beyond the depth of the applied dopant material layer. Suitable temperature and oxidizing conditions are maintained for a time sufficient to produce a self-supporting ceramic body.

Abstract: A method of making self-supporting ceramic composite structures having filler embedded therein includes infiltrating a permeable mass of filler with polycrystalline material comprising an oxidation reaction product obtained by oxidation of a parent metal such as aluminum and optionally containing therein non-oxidized constituents of the parent metal. The structure is formed by placing a parent metal adjacent to a permeable filler and heating the assembly to melt the parent metal and provide a molten body of parent metal which is contacted with a suitable vapor-phase oxidant. Within a certain temperature region and optionally aided by one or more dopants in or on the parent metal, molten parent metal will migrate through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow so as to embed the adjacent filler and provide the composite structure.

Abstract: A method for producing a self-supporting ceramic composite body which comprises preparing a polycrystalline material as the oxidation reaction product of a parent metal with a vapor-phase oxidant, comminuting the resulting material to a particulate, forming a permeable mass of said particulate as filler, and infiltrating said particulate with an oxidation reaction product of a parent metal with a vapor-phase oxidant, thereby forming said ceramic composite body.

Abstract: An assembly for the preparation of ceramic composite structures includes a segmented container within which a permeable filler is retained and a parent metal body is contacted with the bed of permeable filler. The segmented container is comprised of one or more segments made of a material, such as an INCONEL alloy, which has a coefficient of thermal expansion which is significantly greater than that of the filler. The segments are arranged to define between or among them one or more expansion joints which are effective to accommodate circumferential thermal expansion of the segments to thereby inhibit or prevent volumetric expansion of the container. A method of forming ceramic composite structures includes heating the resulting assembly in the presence of an oxidant to melt and oxidize the parent metal, e.g., aluminum, to form a polycrystalline material comprising an oxidation reaction product which grows through the mass of filler to embed it and thus form the composite structure.

Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal. The method, includes embedding the mold of parent metal within a conformable bed of filler to provide there in a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surrounding bed of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated of the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold.

Abstract: A method of producing self-supporting ceramic structures includes providing a first self-supporting ceramic body comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a first molten parent metal with a first oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of said first ceramic body. A second ceramic body is used to form, by reaction with a vapor-phase oxidant, a second polycrystalline material which is infiltrated into the porosity of at least a zone of said first ceramic body.

Abstract: Ceramic bodies are bonded together via a layer of an oxidation reaction product of a molten metal, which metal is present in one or both of the ceramic bodies prior to bonding. At least one of the ceramic bodies comprises a ceramic product formed by the oxidation reaction of molten parent metal (e.g., alumina from molten aluminum) and grown as molten metal is transported through, and oxidized on the surface of, its own oxidation product. One or both of the ceramic bodies used in the bonding process contains surface-accessible channels of residual metal, i.e., metal channels which have resulted from molten-metal transport during the ceramic growth process. When the suitably assembled ceramic bodies are heated in an oxidizing atmosphere at a temperature above the melting point of the residual metal, molten metal at the surface of the ceramic body reacts with the atmosphereic oxidant so as to bond the facing surfaces together by a layer of the oxidation reaction product of the molten metal formed therebetween.

Abstract: The present invention provides a method for producing a self-supporting ceramic composite by the oxidation of a parent metal to form a polycrystalline ceramic material consisting essentially of the oxidation reaction product of the parent metal with an oxidant, including a vapor-phase oxidant, and, optionally, one or more metallic constituents. A permeable filler material, such as a preform, with at least one surface bearing a permeable stratum, is contacted with a body of molten parent metal heated to a temperature above its melting point but below the melting point of the oxidation reaction product.

Abstract: A method is provided of producing a self-supporting ceramic composite structure having one or more encasement members, such as an encasing steel sleeve, joined to it by growth of the ceramic material to engagement surface(s) of the encasement member(s). A parent metal is contacted with a body of filler which is encased by the encasement member(s). The resulting assembly is heated to melt and oxidize the parent metal, e.g., aluminum, to form a polycrystalline material comprising an oxidation reaction product which grows through the doby of filler and stops at the engagement surface(s) of the encasement member(s) which thereby determines the surface geometry of the grown ceramic matrix. Upon cooling, the encasement member(s) is shrink-fitted about the ceramic composite body. The invention also provides the resultant articles, for example, a ceramic composite body having a stainless steel member affixed thereto.

Abstract: A method for producing an alumina of high purity, which comprises forming an oxidation reaction product of an aluminum parent metal and an oxygen-containing vapor-phase oxidant, comminuting the resulting ceramic body, and leaching any non-alumina materials therefrom, and recovering said substantially pure alumina material.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal with a boron source typically resulting in a composite comprising a parent metal boride and metal. The mass to be infiltrated may contain one or more inert fillers admixed with the boron source to produce a composite by reactive infiltration, which composite comprises a matrix of metal and parent metal boride embedding the filler. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing varying volume percents of ceramic, metal and/or porosity.

Abstract: Novel self-supporting ceramic structures are produced by the oxidation reaction of a molten metal precursor with a vapor-phase oxidant to form an oxidation reaction product. Molten metal is drawn through the oxidation reaction product towards the oxidant to cause continued growth of the product at the interface between oxidant and previously formed product. This reaction or growth is continued to form a thick, self-supporting ceramic body. The resulting ceramic material of the polycrystalline growth product consists essentially of an oxidation reaction product and, optionally, one or more non-oxidized constituents of the metal precursor.

Abstract: The non-catylic steam reformation system is provided whereby the hydrocarbon is continually decomposed in the presence of superheated steam which serves to fix the product gases. The reactants are held at a high temperature and the reaction controlled to continuously achieve an equilibrium between thermal cracking of the hydrocarbon and the oxidation of resultant coke deposits by the superheated steam so that there is a substantially constant coke inventory.