Abstract: Preceramic polymers which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by reacting about 0.2-5.0 part by weight of a bis- or tris(dialkylamino)borane with one part by weight of a polysilazane in an organic solvent.

Abstract: Silicon carbide-coated carbonaceous substrates are overcoated with one or more ceramic layers derived from an organoborosilazane polymer solution containing 0-60% by weight of dispersed ceramic or preceramic powdered solids to seal the silicon carbide coating and provide better resistance to oxidative deterioration at elevated temperatures; the organoborosilazane polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent. The thus-coated substrates are optionally overcoated with a buffer layer and then with one or more ceramic layers derived from polysilazane solutions or dispersions.

Abstract: Coatings compositions, which are useful as buffer layers between ceramic layers derived from polysilazane-containing compositions and ceramic layers derived from organoborosilazane polymer-containing compositions, are obtained by dissolving (A) a Group IIIa metal hydrocarbyloxide, such as aluminum sec-butoxide, (B) a Group IVb metal hydrocarbyloxide, such as zirconium propoxide, (C) a bis-, tris-, or tetrakis(dialkylamino)metal of Group IVb, such as tetrakis(diethylamino)titanium, (D) a polysilazane and/or a bis-, tris-, or tetrakis(dialkylamino)silane, such as tetrakis(dimethylamino)silane, and (E) optionally also a cyclopentadienyl Group IVb metal halide, such as bis(cyclopentadienyl)zirconium dichloride, in an organic solvent, the amounts of ingredients A-D being such that each constitutes 1-50% of their combined weights, and the amount of ingredient E being such that it constitutes 0-20% of the combined weights of the ingredients.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0.4-1 part by weight of a metal boride in an organic solvent solution containing one part by weight of an organoborosilazane polymer prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with a solution of one part by weight of a polysilazane in an organic solvent.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0.1-4 parts by weight of silicon boride in one part by weight of a polysilazane in solution in an organic solvent.

Abstract: Preceramic compositions which are useful in providing protective ceramic coatings on silica foams, carbon/carbon composites, graphite, and other materials are prepared by dispersing about 0-3 parts by weight of aluminum-silicon eutectic, about 0-4 parts by weight of silicon carbide, about 1.5-5 parts by weight of silicon boride, and about 0.4-5 parts by weight of silicon metal in a solution of one part by weight of a polysilazane in an organic solvent.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbonaceous and other normally oxidizable substrates are prepared by dispersing about 0.4-3.0 parts by weight of a ceramic powder selected from silicon carbide, silicon nitride, and mixtures thereof with one another and/or with up to about 90% by weight of (1) a metal boride or (2) a mixture of a metal boride and zirconium metal in one part by weight of a polysilazane.

Abstract: Preceramic polymer dispersions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0-3 parts by weight of aluminum-silicon eutectic, about 0-4 parts by weight of silicon carbide, about 1.5-5 parts by weight of silicon boride, and about 0.4-5 parts by weight of silicon metal in a solution of an organoborosilazane polymer in an organic solvent, the organoborosilazane polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane.

Abstract: Preceramic compositions which are useful in providing protective ceramic coatings on carbon/carbon composites, graphite, and other carbonaceous materials are prepared by dispersing about 0.4-1.5 parts by weight of silicon carbide, silicon nitride, or a mixture thereof in a solution of one part by weight of a polysilazane in about 2.5-10 parts by weight of a liquid aromatic hydrocarbon.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polycarbosilane in an organic solvent.

Abstract: Preceramic polymers which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by reacting about 0.25-20 parts by weight of a trialkyl- or trialkoxyboroxine in which the alkyl or alkoxy groups contain 1-6 carbons with one part by weight of a poly-silazane to form an organoborosilazane polymer.

Abstract: Preceramic polymer dispersions which have particular utility in providing protective ceramic coatings having low moisture sensitivity on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0-3 parts by weight of aluminum-silicon eutectic, about 0-4 parts by weight of silicon carbide, about 1.5-5 parts by weight of silicon boride, and about 0.4-5 parts by weight of silicon metal in a solution or dispesion obtained by dispersing about 0.1-1.0 parts by weight of a Group IIA metal salt in an organoborosilazane polymer obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent and, if desired, heating the dispersion to convert it to a solution.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polycarbosilane in an organic solvent.

Abstract: Preceramic polymer dispersions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0.25-2.0 parts by weight of silicon metal, about 0.25-2.0 parts by weight of silicon tetraboride, about 0.25-2.0 parts by weight of silicon hexaboride, and about 0-2 parts by weight of silicon carbide in the product obtained by dispersing about 0.1-1.0 part by weight of a Group IVA metal salt or an organometallic Group IVA metal compound in an organic solvent solution containing one part by weight of a polysilazane and, if desired, heating the Group IVA compound/polysilazane dispersion to convert it to a solution.

Abstract: Preceramic polymers which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysiloxazane in an organic solvent to form an organoborosiloxazane polymer.

Abstract: Preceramic polymers which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials, are prepared by reacting about 0.25-20 parts by weight of a triaryloxyboroxine with one part by weight of a polysilazane to form a organoborosilazane polymer.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings having low moisture sensitivity on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0.1-1.0 part by weight of a Group IIA metal salt with an organoborosilazane polymer solution obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent and, if desired, heating the dispersion to convert it to a solution.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polycarbosilane in an organic solvent.

Abstract: Coking in and around the injector nozzles of indirect injection compression ignition engines is reduced by means of distillate fuel with which has been blended suitable concentrations of (i) organic nitrate ignition accelerator, and (ii) a carboxylic acid ester.Also described are additive mixtures of (i) and (ii) for use in distillate fuels in amounts sufficient to reduce the coking tendencies of such fuels when used in the operation of indirect injection compression ignition engines.

Abstract: Coking in and around the injector nozzles of indirect injection compression ignition engines is reduced by means of distillate fuel with which has been blended suitable concentrations of (i) organic nitrate ignition accelerator, and (ii) a sterically hindered 4,4'-thiobis phenol.Also described are additive mixtures of (i) and (ii) for use in distillate fuels in amounts sufficient to reduce the coking tendencies of such fuels when used in the operation of indirect injection compression ignition engines.