Abstract: The present invention relates to forming a metal matrix composite between at least two bodies having a similar or a different chemical composition, the metal matrix composite functioning as a bonding means which bond to or fixes the bodies together. Particularly, a metal matrix composite is produced by a spontaneous infiltration technique by providing a filler material or preform with an infiltration enhancer and/or an infiltration enhancer precursor and/or and infiltrating atmosphere, which are in communication with the filler material or preform at least at some point during the process. Molten matrix metal then spontaneously infiltrates the filler material or preform, whereby the metal matrix composite serves to bond together two or more bodies.

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 the presence of an oxidant at a temperature above the melting point of the residual metal, molten metal at the surface of at least one of the ceramic bodies reacts with the oxidant to form a layer of oxidation reaction product, which may or may not incorporate at least one filler material.

Abstract: In the present invention there is provided a method for producing abrasive ceramic and ceramic composite material characterized by an abrasive grain as the comminuted form of a polycrystalline ceramic material. The abrasive grains of the present invention consist essentially of the oxidation reaction product of a parent metal precursor with a vapor phase oxidant, and, optionally one or more metallic constituents such as non-oxidized constituents of the parent metal. There is also provided a method for producing abrasive grains which additionally consist of one or more inert filler materials.

Abstract: A method for producing a self-supporting ceramic composite body having a negative pattern which inversely replicates the positive pattern of a parent metal precursor having thereon a positive pattern section which is emplaced in conforming engagement with a bed of conformable filler. The parent metal precursor, which also has a non-replicating section, is melted and reacted with an oxidant to form a polycrystalline oxidation reaction product which grows primarily only from the positive pattern section of the parent metal precursor and through the filler. The molten parent metal is drawn through the growing polycrystalline material and oxidized at the interface between the oxidant and previously formed oxidation reaction product. The reaction is continued for sufficient time to at least partially embed the filler within the oxidation reaction product and form the ceramic composite body containing a negative pattern which inversely replicates the positive pattern of the parent metal precursor.

Abstract: A method of producing self-supporting ceramic a ceramic composite structures comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a body of molten parent metal with an oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of the ceramic body. A second polycrystalline ceramic or ceramic composite material is incorporated into the porosity of the ceramic or ceramic composite body to modify or contribute to its properties.

Abstract: Coated ceramic filler materials comprised of ceramic particles, fibers, whiskers, etc. having at least two substantially continuous coatings thereon are provided. The coatings are selected so that the interfacial shear strength between the ceramic filler material and the first coating, between coatings, or between the outer coating and the surrounding matrix material, are not equal so as to permit debonding and pull-out when fracture occurs. The resultant, multi-coated ceramic filler materials may be employed to provide ceramic matrix composites with increased fracture toughness. The ceramic filler materials are designed to be particularly compatible with ceramic matrices formed by directed oxidation of precursor metals.

Abstract: The present invention relates to a novel method for forming metal matrix composite bodies and the novel products produced therefrom. A negative shape or cavity, which is complementary to the desired metal matrix composite body to be produced, is first formed. The formed cavity is thereafter filled with a permeable mass of filler material. Molten matrix metal is then induced to spontaneously infiltrate the filled cavity. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are also in communication with the filler material, at least at some point during the process, which permits the matrix metal, when made molten, to spontaneously infiltrate the permeable mass of filler material, which at some point during the processing, may become self-supporting. In a preferred embodiment, cavities can be produced by a process which is similar to the so-called lost-wax process.

Abstract: A method is provided for producing a self-supporting ceramic body comprising a polycrystalline material comprised of the oxidation reaction product of a parent metal and having therein one or more channels which inversely replicate the geometry of a configured fugative metal. The method includes providing an assembly of the configured fugitive metal and the parent metal, optionally including a bed of permeable filler, and heating the assembly to form a body of molten parent metal. The molten parent metal is oxidized under selected conditions to grow the polycrystalline material to engulf the configured fugitive metal (and to infiltrate the filler, if the filler is present) and to cause the fugitive metal to disperse into the engulfing polycrystalline material thereby leaving behind as the one or more channels the space formerly occupied by the configured fugitive metal.

Abstract: The present invention relates to a novel process for forming macrocomposite bodies and the novel bodies formed thereby. Particularly, a suitable matrix metal, typically in a molten state, is in contact with a suitable mass of filler material or preform located adjacent to, or in contact with, at least one second material in the presence of a suitable reactive atmosphere in an impermeable container, at least at some point during the process, which permits a reaction to occur between the reactive atmosphere and the molten matrix metal and/or mass of filler material or preform and/or impermeable container, thereby causing molten matrix metal to infiltrate the mass of filler material or preform due to, at least in part, the creation of a self-generated vacuum. Such self-generated vacuum infiltration occurs without the application of any external pressure or vacuum.

Abstract: Self supporting ceramic composite structures having filler embedded therein produced by a method which 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 self-supporting ceramic body produced by oxidation of a molten precursor metal with a vapor-phase oxidant to form an oxidation reaction product and inducing a molten flux comprising said molten precursor metal through said oxidation reaction product. A second metal is incorporated into said molten flux during the oxidation reaction. The resulting ceramic body includes sufficient second metal such that one or more properties of said ceramic body are at least partially affected by the presence and properties of said second metal in the metallic constituent.

Abstract: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e. a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: The invention concerns self-supporting ceramic structures, including ceramic composite structures embedding a filler, and methods of making them. The ceramic structures comprise a polycrystalline material made by oxidation of a body of molten parent metal with an oxidant. The polycrystalline material has a first region substrate surmounted by a terminal region stratum which is integral with the first region. The terminal region stratum, may be harder and of denser, finer crystalline structure than the first region substrate, is formed in a reaction stage subsequent to the reaction stage in which the first region of polycrystalline material is formed. Growth of the first stage is attained by attenuating or interrupting the transport of molten parent metal to the first region under conditions which nonetheless leave or maintain therein enough oxidizable molten parent metal to form the polycrystalline material of the terminal region.

Abstract: The present invention relates to the formation of a metal matrix composite body by a spontaneous infiltration technique. Particularly, an infiltration enhancer and/or infiltration enhancer precursor can be positioned at least partially between or at an interface between a matrix metal and a filler material (or preform) which is to be infiltrated by molten matrix metal. Moreover, at least at some point during the process, an infiltrating atmosphere may be in communication with the filler material or preform and/or matrix metal.

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 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 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: In a method for producing ceramic body by oxidation of a parent metal having a graded microstructure characterized by a plurality of zones differing from each other in one or more properties 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.

Abstract: This invention relates generally to a novel method of manufacturing a composite body, such as a ZrB.sub.2 -ZrC-Zr (optional) composite body, by utilizing a post-treatment process and to the novel products made thereby. More particularly, the invention relates to a method of modifying a composite body comprising one or more boron-containing compounds (e.g., a boride or a boride and a carbide) which has been made by the reactive infiltration of a molten parent metal into a bed or mass containing boron carbide, and optionally one or more inert fillers, to form the body.

Abstract: Self-supporting ceramic composite bodies of desired shape are produced by infiltrating a permeable self-supporting preform with polycrystalline matrix material comprising an oxidation reaction product obtained by oxidation of a parent metal precursor, such as aluminum, and optionally containing therein metallic constituents. The composite body is formed by contacting a zone of a permeable self-supporting preform, having at least one defined surface boundary spaced from said contacting zone, with a body of molten metal which is reacted with a suitable vapor-phase oxidant to form an oxidation reaction product.

Abstract: A method of producing shaped, self-supporting ceramic bodies includes preparing a mold by applying a permeable, conformable material to a shape-defining surface of an expendable pattern. The permeable, conformable material, when set or stable, provides a mold with a shaped surface which is defined by, and is therefore substantially congruent to, the shape-defining surface. Upon heating, the material of the expendable pattern combusts or volatilizes and thus establishes the shaped cavity mold. A molten parent metal is then vaporized with a vapor-phase oxidant in such a manner as to form a ceramic body which grows into the mold cavity, and is shaped by it. The ceramic body is recovered from the mold having a shaped surface replicating the shape-defining surface of the expandable pattern.

Abstract: The present invention relates to a novel method for forming metal matrix composite bodies. Particularly, a permeable mass of filler material is formed into a preform. An infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are also in communication with the preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the preform when the preform is placed into the molten matrix metal. A means for maintaining the preform at least partially below the surface of the molten matrix metal can also be utilized.