Abstract: This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies.

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: This invention broadly relates to methods for producing self-supporting silicon carbide and silicon carbide composite bodies. More particularly, this invention relates to silicon carbide and silicon carbide composites, grown by the oxidation reaction of a silicon metal with a gas comprising at least one gas selected from the group consisting of fluorinated hydrocarbon gases, chlorohydrocarbon gases, and chlorofluorocarbon gases.

Abstract: This invention relates generally to a novel method for removing metal from a formed self-supporting body. A self-supporting body is made by reactively infiltrating a molten parent metal into a bed or mass containing a boron donor material and a carbon donor material (e.g., boron carbide) and/or a boron donor material and a nitrogen donor material (e.g., boron nitride) and, optionally, one or more inert fillers. Once the self-supporting body is formed, it is then subjected to appropriate conditions which causes metallic constituent contained in the self-supporting body to be at least partially removed.

Abstract: In the present invention, there is described a setup for producing a self-supporting ceramic body or ceramic composite by the oxidation of a parent metal to form a polycrystalline ceramic material comprising the oxidation reaction product of said parent metal with an oxidant, including a vapor-phase oxidant, and optionally one or more metallic constituents dispersed throughout the polycrystalline ceramic material. The setup is used with a method which comprises the steps of providing at least a portion of said parent metal with a barrier means at least partially spaced from said parent metal for establishing at least one surface of the ceramic body, and heating said parent metal to a temperature above its melting point but below the melting point of the oxidation reaction product to form a body of molten metal. At that temperature, the molten metal is reacted with the oxidant, thus forming the oxidation reaction product.

Abstract: There is provided a method for producing a self-supporting ceramic composite comprising (1) a ceramic matrix obtained by oxidation of an aluminum zinc alloy to form a polycrystalline oxidation reaction product of the metal with an oxidant, and (2) one or more fillers embedded by the matrix. The metal alloy and permeable mass of filler having at least one defined surface boundary are oriented relative to each other so that formation of the oxidation reaction product will occur into said mass of filler and in a direction towards said defined surface boundary. On heating the metal to a first temperature above its melting point but below the melting point of said oxidation reaction product to form a body of molten parent metal, the molten metal reacts with said oxidant to form said oxidation reaction product which infiltrates said mass of filler to said defined surface boundary.

Abstract: Organometallic ceramic precursor binders are used to fabricate shaped bodies by different techniques. Exemplary shape making techniques which utilize hardenable, liquid, organometallic, ceramic precursor binders include the fabrication of negatives of parts to be made (e.g., sand molds and sand cores for metalcasting, etc.), as well as utilizing ceramic precursor binders to make shapes directly (e.g., brake shoes, brake pads, clutch parts, grinding wheels, polymer concrete, refractory patches and liners, etc.). A preferred embodiment of the invention involves the fabrication of preforms used in the formation of composite articles.

Abstract: The present invention relates to a method of armoring a vehicle with a novel armor material. Particularly, a metal matrix composite body is formed with a filler material and an aluminum matrix metal, wherein the filler material comprises magnesia or titanium diboride and is present in an amount of at least 40 percent by volume. The metal matrix composite body is then placed on a portion of a vehicle.

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: 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 which is harder and of denser, finer crystalline structure than the first region substrate and 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 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: This invention relates generally to a novel method of manufacturing a composite body. More particularly, the present invention relates to a method for modifying the resultant properties of a composite body, by, for example, minimizing the amount of porosity present in the composite body. Moreover, additives, whether used alone or in combination, (1) can be admixed with the permeable mass, (2) can be mixed or alloyed with the parent metal, (3) can be placed at an interface between the parent metal and the preform or mass of filler material, (4) or any combination of the aforementioned methods, to modify properties of the resultant composite body. Particularly, additives such as VC, NbC, WC, W.sub.2 B.sub.5, TaC, ZrC, ZrB.sub.2, SiB.sub.6, SiC, MgO, Al.sub.2 O.sub.3, ZrO.sub.2, CeO.sub.2, Y.sub.2 O.sub.3, La.sub.2 O.sub.3, MgAl.sub.2 O.sub.4, HfO.sub.2, ZrSiO.sub.4, Yb.sub.2 O.sub.3 and Mo.sub.2 B.sub.

Abstract: This invention relates generally to a novel method for joining at least one first self-supporting body to at least one second self-supporting body which is similar in composition to or different in composition from said at least one first self-supporting body and to novel products which result from such joining. In some of its more specific aspects, this invention relates to different techniques for joining ceramic matrix composite bodies to other ceramic matrix composite bodies of similar characteristics and for joining ceramic matrix composite bodies to bodies which have different characteristics (e.g., metals). The ceramic matrix composite bodies of this invention are produced by a reactive infiltration of a molten parent metal into a bed or mass containing at least one of a boron source material, a carbon source material, and a nitrogen source material and, optionally, one or more inert fillers.

Abstract: A method for manufacture of Group IVB metal carbide comprising a carbide of a metal selected from the group consisting of titanium, hafnium and zirconium ceramic composites is provided wherein a permeable mass of filler and carbon is contacted with a molten Group IVB metal. The molten metal is maintained in contact with the permeable mass for a sufficient period to infiltrate the permeable mass and to react the molten metal with the carbon source to form a Group IVB metal carbide composite. The permeable mass may comprise a Group IVB metal carbide, or other inert filler, or a combination of filler materials.

Abstract: A ceramic-reinforced aluminum matrix composite is formed by contacting a molten aluminum-magnesium alloy with a permeable mass of ceramic material in the presence of a gas comprising from about 10 to 100% nitrogen, by volume, balance non-oxidizing gas, e.g., hydrogen or argon. Under these conditions, the molten alloy spontaneously infiltrates the ceramic mass under normal atmospheric pressures. A solid body of the alloy can be placed adjacent a permeable bedding of ceramic material, and brought to the molten state, preferably to at least about 700.degree. C., in order to form the aluminum matrix composite by infiltration. In addition to magnesium, auxiliary alloying elements may be employed with aluminum. The resulting composite products may contain a discontinuous aluminum nitride phase in the aluminum matrix and/or an aluminum nitride external surface layer.

Abstract: The present invention generally relates to mechanisms for preventing undesirable oxidation (i.e., oxidation protection mechanisms) of reinforcement materials in composite bodies. The oxidation protection mechanisms include getterer materials which are added to the composite body which gather or scavenge undesirable oxidants which may enter the composite body. The getterer materials may be placed into at least a portion of the matrix such that any desirable oxidant approaching, for example, a fiber reinforcement, would be scavenged by (e.g., reacted with) the getterer. Ceramic filler materials which serve as reinforcements may have a plurality of super-imposed coatings thereon, at least one of which coatings may function as a getterer. The coated materials may be useful as reinforcing materials in ceramic matrix composites to provide improved mechanical properties such as fracture toughness.

Abstract: A method is provided for producing a self-supporting ceramic composite body having a plurality of spaced apart wall members, each wall member having a bounded cross-section for defining substantially continuous, fluid passageways. The wall members generally inversely replicate in opposed directions the geometry of a positive pattern. Each of the wall members, which are axially aligned, comprises a ceramic matrix having a filler embedded therein, and is obtained by the oxidation reaction of a parent metal to form a polycrystalline material which consists essentially of the oxidation reaction product of the parent metal with an oxidant and, optionally, one or more metals, e.g. nonoxidized constituents of the parent metal.

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 or an infiltration enhancer precursor 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. In a preferred embodiment a reservoir may be employed to supply a second metal which has a different composition from the first source of matrix metal.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies, and novel products made thereby. In its more specific aspects, this invention relates to a method for producing self-supporting bodies comprising one or more boron-containing compounds (e.g., a boride or a boride and a carbide, etc.) by reactive infiltration of molten parent metal into a preform comprising boron carbide or a boron donor material combined with a carbon donor material and, optionally, one or more inert fillers, to form the body. Specifically, a boron carbide material or combination of a boron donor material and a carbon donor material, and in either case, optionally, one or more inert fillers, are sedimentation cast, spray coated, tapped, slip cast, pressed, etc., onto or into a body and into a particular desired shape.

Abstract: The present invention relates to the formation of bodies having graded properties. Particularly, the invention provides a method for forming a metal matrix composite body having graded properties. The graded properties are achieved by, for example, locating differing amounts of filler material in different portions of a formed body and/or locating different compositions of filler material in different portions of a formed body and/or locating different sizes of filler materials in different portions of a formed body. In addition, the invention provides for the formation of macrocomposite bodies wherein, for example, an excess of matrix metal can be integrally bonded or attached to a graded metal matrix composite portion of a macrocomposite body.

Abstract: The present invention relates to a novel process for forming internal shapes in metal matrix composite bodies. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with a filler material or a preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the filler material or preform. Additionally, the filler material or preform may contain a mandrel which is capable of surviving the infiltration process, said mandrel being removed after infiltration has occurred. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum.