Abstract: A method for producing ceramic matrix composites wherein the method has the steps of impregnating crystalline silicon carbide fibers coated with an interfacial coating with a ceramic matrix precursor; forming the impregnated fibers into the desired shape; curing the shape; and heating the cured shape to a temperature in the range of greater than 1450° C. to 1800° C. to convert the ceramic matrix precursor into a crystal containing ceramic. A densification step may be optionally carried out until the desired porosity/density of the ceramic matrix composite is achieved.

Abstract: This invention pertains to a method of forming a fiber-reinforced ceramic matrix composite comprising: (a) impregnating a ceramic fiber coated with at least one layer binary coating comprised of boron nitride and silicon nitride wherein the silicon nitride is applied over the boron nitride with a preceramic composition comprising a curable preceramic polymer; (b) forming the impregnated fibers into a desired shape; (c) curing the formed impregnated fibers; (d) heating the cured impregnated fibers of (c) to a temperature of at least 1000° C. in an inert atmosphere for a time effective to convert the preceramic polymer to a ceramic.

Abstract: This invention pertains to ceramic matrix composites that comprise the coated ceramic fibers wherein the coating comprises at least one binary coating of boron nitride (BN) and silicon nitride (Si3N4) within ceramic matrices derived from curable preceramic polymers. The composites can be formed into complex shapes which have good oxidation resistance at high temperature, good resistance to moisture high flexural strength and are resistant to moisture.

Abstract: This invention pertains to ceramic matrix composites that comprise the coated ceramic fibers wherein the coating comprises at least one binary coating of boron nitride (BN) and silicon nitride (Si3N4) within ceramic matrices derived from curable preceramic polymers. The composites can be formed into complex shapes which have good oxidation resistance at high temperature, good resistance to moisture high flexural strength and are resistant to moisture.

Abstract: A method for changing the dielectric properties of a polymer impregnated and pyrolyzed ceramic matrix composite (polymer impregnated and pyrolyzed ceramic matrix composite) is disclosed. The polymer impregnated and pyrolyzed ceramic matrix composite can be used in aircraft and turbine engines. polymer impregnated and pyrolyzed ceramic matrix composite comprises a ceramic matrix, a reinforcing fiber, and at least 1 additive used to change dielectric properties (dielectric constant and loss factor). The additive can be a low dielectric constant material having a dielectric constant in the range of 1 to 7.5. The low dielectric constant material can be an oxide such as silica or aluminosilicate or a non-oxide such as silicon nitride, boron nitride, or silicon carbide. The low dielectric constant material can be incorporated in the ceramic matrix as a filler.

Abstract: Fiber reinforced ceramic matrix composites are prepared by coating refractory fibers having a interfacial coating thereon with a curable preceramic polymer having a char which contains greater than about 50% sealant oxide atoms followed by forming the coated fibers into the desired shape, curing the coated fibers to form a pre-preg, heating the pre-preg to form a composite and heating the composite in an oxidizing environment to form an in situ sealant oxide coating on the composite. The resultant composites have good oxidation resistance at high temperature as well as good strength and toughness.

Abstract: Method of preparing a batch of non-basic refractory gunning mix for forming a refractory monolith on its situs of use by mixing non-basic refractory aggregate and calcium aluminate cement with from about 0.5 to 25%, on a cement basis, of calcium chloride hydrate and mixing the resulting batch with water to allow gunning.

Abstract: This invention relates to refractory castables containing a heat resistant aggregate and calcium aluminate cement plus the addition of +35 mesh silicon carbide wherein such castable may be used at temperatures up to 3200.degree. F. with the required strength.