Abstract: There are disclosed inventions relating to tubular hybrid metal/ceramic composites and the methods of making them wherein the ceramic chosen has a lower thermal expansion than that of the metal.

Abstract: The present invention provides a method for making a ceramic matrix composite comprising forming an infiltrated fiber reinforcement by infiltrating a plurality of plies of a fibrous material with a precursor polymer which decomposes to a substantially pure product selected from the group consisting of a refractory metal carbide and a refractory metal boride, and exposing the infiltrated fiber reinforcement to conditions effective to cure the precursor polymer and to decompose the precursor polymer to said substantially pure product.

Abstract: A method of making a ceramic composite wherein a polymeric ceramic precursor or fiber reinforcement infiltrated with a polymeric ceramic precursor is associated with at least one metallic element to form a preceramic composite and the said composite is pyrolyzed by high frequency microwave radiation, preferably in the form of a beam, until the polymeric ceramic precursor is converted into a ceramic having the at least one metallic element integrally formed as part of said ceramic. The products obtained by such method comprising ceramic metal composites formed by pyrolyzing a preceramic composite to high frequency microwave radiation until the polymeric ceramic precursor is converted into a ceramic having at least one metallic element integrally formed as a part of said component.

Abstract: A method of making a ceramic composite wherein a polymeric ceramic precursor or fiber reinforcement infiltrated with a polymeric ceramic precursor is associated with at least one metallic element to form a preceramic composite and the said composite is pyrolyzed by high frequency microwave radiation, preferably in the form of a beam, until the polymeric ceramic precursor is converted into a ceramic having the at least one metallic element integrally formed as part of said ceramic.

Abstract: The present invention provides a method for making a high temperature coating comprising applying to a surface a precursor polymer which decomposes to a product selected from the group consisting of a refractory metal carbide and a refractory metal boride, and exposing the precursor polymer to conditions effective to decompose the precursor polymer to the product.

Abstract: The present invention provides a method for making a ceramic matrix composite comprising forming an infiltrated fiber reinforcement by infiltrating a plurality of plies of a fibrous material with a precursor polymer which decomposes to a substantially pure product selected from the group consisting of a refractory metal carbide and a refractory metal boride, and exposing the infiltrated fiber reinforcement to conditions effective to cure the precursor polymer and to decompose the precursor polymer to said substantially pure product.

Abstract: The present invention provides a method for producing precursor polymers which decompose to a substantially pure refractory metal carbide or refractory metal boride. The method comprises mixing a transition metal compound with either (a) an organometallic, or (b) a backbone polymer comprising a plurality of unsaturated carbon-carbon bonds. The mixing occurs under conditions effective to form organo-transition metal complexes The organometallic (a), comprises either a borane, a carborane, or an organometallic comprising a metal and at least one unsaturated carbon-carbon bond. When an organometallic (a) is used, the transition metal complexes must be polymerized to form the precursor polymers. When a backbone polymer (b) is used, the transition metal complexes, themselves, comprise the precursor polymers. The refractory metal carbides or metal borides formed upon decomposition of these precursor polymers may be used to make ceramic matrix composites and high temperature coatings.

Abstract: Low dielectric compounds, preferably silicon nitride precursors such as polycarbosilazanes, are mixed with a sufficient quantity of a silicon carbide additive to enhance absorption of electromagnetic energy by the mixture, thereby permitting efficient and effective curing of low dielectric compounds using electromagnetic energy.

Abstract: A method of repairing a damaged area of a thermal barrier coating on a component which is subjected to a hostile thermal environment, which comprises cleaning the damaged area, applying a partially stabilized zirconium sol-gel to the area, and pyrolizing the sol-gel to form a TBC repair layer.

Abstract: The present invention provides a method for making a ceramic matrix composite comprising forming an infiltrated fiber reinforcement by infiltrating a plurality of plies of a fibrous material with a precursor polymer which decomposes to a substantially pure product selected from the group consisting of a refractory metal carbide and a refractory metal boride, and exposing the infiltrated fiber reinforcement to conditions effective to cure the precursor polymer and to decompose the precursor polymer to said substantially pure product.

Abstract: The present invention provides a method for making a high temperature coating comprising applying to a surface a precursor polymer which decomposes to a substantially pure product selected from the group consisting of a refractory metal carbide and a refractory metal boride, and exposing the precursor polymer to conditions effective to decompose the precursor polymer to said substantially pure product.

Abstract: A hydrocarbon-independent lean-burn NO.sub.x catalyst for treatment of products of combustion includes a porous support impregnated with two transition metals. The first transition metal has a stable upper oxidation state that is reducible to a lower oxidation state in the presence of carbon monoxide which is oxidized in the presence of the first transition metal to form carbon dioxide. The second transition metal has a stable lower oxidation state and is capable of being raised to a higher oxidation state in the presence of NO.sub.x which is reduced to nitrogen and oxygen in the presence of the second metal. The first and second metals cooperate to form a redox reaction system which regenerates the active form of the catalyst by raising the first metal to its stable oxidation state and reducing the second metal to it stable lower oxidation state by electron transfer between the first and second metals.

Abstract: A method of producing silicon nitride ceramics and silicon nitride ceramic composites. A mixture comprising a polysilazane and an additive effective to increase coupling between the mixture and electromagnetic energy is converted to a preceramic intermediate. The preceramic intermediate is treated with electromagnetic energy and thereby converted to a silicon nitride ceramic and/or a silicon nitride ceramic composite.

Abstract: There is disclosed a method of making polysilanes by polymerization of a silane in the presence of a catalyst comprising a phosphine-stabilized polyhydride of an early transition metal of Groups 4 to 7 of the Periodic Table and the resultant polysilanes which have a molecular weight higher than 1,000 and a polydispersity below about 2.

Abstract: A method of repairing damage to an oxidation-resistant layer on a carbon-carbon composite wherein a composition consisting essentially of a polymeric thermosetting polysilazane and a ceramic powder is applied to the damaged area, cured, and fired.

Abstract: A method of making fiber-reinforced preceramic and ceramic composites by infiltrating a preform of heat-resistant fibers with a solvent-free thermosetting preceramic polysilazane poller. The invention also comprises the resultant preceramic and ceramic composites.

Abstract: An adhesive composition for joining carbon-carbon composites comprising a polymeric thermosetting polysilazane, a ceramic powder, silicon powder, and carbon powder. The invention also comprises the method of making carbon-carbon composite structures utilizing such adhesive composition and to the resultant products.

Abstract: An adhesive composition for joining carbon--carbon composites comprising a polymeric thermosetting polysilazane, a ceramic powder, silicon powder, and carbon powder. The invention also comprises the method of making carbon--carbon composite structures utilizing such adhesive composition and to the resultant products.

Abstract: A method of making a polysilazane comprising forming a reaction medium comprising at least one halomonosilane, an ammonium compound, and an organic solvent for said at least one halomonosilane, carrying out the reaction between said at least one halomonosilane and said ammonium compound in the absence of any catalyst, oxygen, and moisture at atmospheric pressure and at a temperature of about -80.degree. C. to 50.degree. C. for a time sufficient to form said polysilazane, and separating said polysilazane from said reaction medium.

Abstract: Monosized ceramic particles produced through synergistic combination of monosized latex particles and organometallic reagents in a solvent system. By swelling a poly(vinyltoluene) or other monosized latex with an appropriate organometallic reagent, decomposing the organometallic to ceramic within the latex vehicle, and then removing the latex polymer through thermolysis, monosized ceramic particles are produced. The swelling of the monosized latex particles with the organometallic reagent requires the judicious selection of a solvent system specific to the latex polymer and organic being employed.