摘要:
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, includes embedding the mold of parent metal within a conformable bed of filler to provide therein 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 surroundings 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 by the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold. The method provides ceramic composite articles having therein at least one cavity inversely replicating the shape of the mold which supplied the parent metal for oxidation.
摘要:
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, includes embedding the mold of parent metal within a conformable bed of filler to provide therein 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 surroundings 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 by the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold. The method provides ceramic composite articles having therein at least one cavity inversely replicating the shape of the mold which supplied the parent metal for oxidation.
摘要:
Ceramic bodies (2,4) 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 (2,4) prior to bonding. At least one of the ceramic bodies (2,4) 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 (2,4) 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 (2,4) 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 atmospheric oxidant so as to bond the facing surfaces together by a layer of the oxidation reaction product of the molten metal formed therebetween.
摘要:
The invention relates to a method for producing ceramic composites obtained by oxidation of an aluminum parent metal to form a polycrystalline ceramic material by providing a filler having a coating of a silicon source on at least a portion of said filler different in composition from the primary composition of said filler, said silicon source possessing intrinsic doping properties. A body of molten parent metal, adjacent a mass of the filler material, reacts with an oxidant to form an oxidation reaction product which infiltrates the adjacent mass of filler thereby forming the ceramic composite.
摘要:
A method is disclosed for producing a ceramic body by oxidation of a parent metal, the ceramic body having a graded microstructure characterized by a plurality of zones differing from each other in one or more properties. The zones in the ceramic body are attained by altering the process conditions during formation of said ceramic body such that a zone of the oxidation reaction product formed posterior to said altering has one or more properties different from a zone of the oxidation reaction product formed anterior to said altering.
摘要:
Ceramic bodies (2,4) 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 (2,4) prior to bonding. At least one of the ceramic bodies (2,4) 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 (2,4) 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 (2,4) 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 atmospheric oxidant so as to bond the facing surfaces together by a layer of the oxidation reaction product of the molten metal formed therebetween.