Abstract: Highly uniform prepreg mats comprising inorganic fibers and powered ceramic matrix materials, useful for the manufacture of ceramic matrix composite articles, are provided by a process wherein continuous fiber tows infiltrated with a thermoplastic suspension of the matrix powder are preheated, uniformly collected on a heated drum or other support, and then cooled and compacted with a pressure roller or the like to achieve a prepreg mat structure characterized by a homogeneous distribution of fibers and ceramic matrix material.

Abstract: A fiber-reinforced ceramic matrix composite article comprising fiber-reinforced surface portions disposed on a ceramic core, the core differing in composition and high temperature properties from the surface portions and the fibers present in the surface portions being of a type normally subject to oxidative deterioration at high temperature, wherein the fibers in the surface portion are provided with protection from high temperature oxidative deterioration such that excellent strength and resistance to high temperature embrittlement are achieved for the composite as a whole.

Abstract: For protection against oxidation or other adverse chemical deterioration, substrates such as carbon, intermetallic aluminides, and refractory metal alloys are provided with barrier coatings of an aluminoborate glass-ceramic coating having a composition, in weight percent, of about 10-55% Al.sub.2 O.sub.3, 4-40% B.sub.2 O.sub.3, up to 70% total of RO, wherein RO consists of one or more alkaline earth metal oxides selected in amounts not exceeding the indicated proportions from the group consisting of up to 70% BaO, up to 60% SrO, up to 40% CaO, and up to 25% MgO, up to 35% total of R.sub.2 O, wherein R.sub.2 O consists of one or more alkali metal oxides selected in amounts not exceeding the indicated proportion from the group consisting of up to 35% Na.sub.2 O, up to 30% K.sub.2 O, and up to 15% Li.sub.2 O, up to 25% total of metal oxides selected from the group consisting of ZnO and MnO, up to 30% of SiO.sub.2, and up to 10% F.

Abstract: Ceramic matrix composite articles of improved high temperature oxidation resistance are provided, the articles comprising reinforcing fibers disposed within a ceramic matrix, the matrix further comprising a minor matrix addition consisting of a dispersion of fluormica crystallites in a proportion effective to improve the oxidation resistance of the article and ranging up to about 20% by weight of the matrix.

Abstract: Ceramic matrix composite articles comprising a matrix phase composed of a silicate glass or glass-ceramic and a matrix reinforcement material disposed within the matrix comprising carbon (e.g., graphite) fibers are described, wherein the fibers are provided with a protective boron nitride surface coating. The mechanical properties of the composites at high temperatures are substantially improved.

Abstract: Fiber-reinforced ceramic matrix composites incorporating a glass-ceramic matrix of lithium aluminosilicate composition in which is disposed a fiber reinforcement phase including at least one layer of unidirectionally oriented fibers (e.g. SiC), the matrix further comprising a whisker reinforcement phase selected from the group of SiC, alumina, HfC and Si.sub.3 N.sub.4, the whiskers imparting substantially improved transverse modulus of rupture strength and interlaminar shear strength to the composite.

Abstract: A method for synthesizing alkaline earth metal-containing ceramic materials by sol-gel processing is described, wherein a sol containing alkoxides or other soluble precursors for a selected ceramic composition, and additionally containing one or more dissolved alkaline earth metal/crown either complexes, is gelled, dried and fired to convert the precursors and complexes to a polycrystalline ceramic product. The crown ether complexes improve alkaline earth metal solubility and the homogeneous incorporation of these metals into the precursor gels and final crystalline products.

Abstract: A ceramic matrix composite article having a varying thickness is fabricated by a process wherein multiple prepreg sheets comprising reinforcing fibers and powdered matrix material are stacked to provide a multi-layer prepreg stack wherein, through each cross-sectional dimension perpendicular to the plane of the sheets, the number of prepreg sheets contributing to the aggregate sheet thickness of the stack varies in proportion to the relative thickness desired in the layered article. The stack may consolidated to a composite article with a smoothly varying thickness profile without undue fiber breakage or ply wrinkling in the composite structure consolidated into a composite article having a smoothly varying thickness profile with reduced internal fiber bowing or breakage. Preferably, the exterior surfaces of the article comprise long, substantially continuous fibers and are free of ply drops.

Abstract: A method for foming glass articles of substantial thickness from unstable glass compositions which normally devitrify when formed by conventional casting or molding processes, is disclosed. The method includes the steps of quench-cooling the glass to form a crystal-free glass feedstock material, and then pressure-consolidating the feedstock at a temperature between the transition temperature and the crystallization temperature of the glass.

Abstract: Thin inorganic sintered structures having strength and flexibility sufficient to permit bending without breakage in at least one direction to a radius of curvature of less than 20 centimeters, methods for making them, and products incorporating them, are described. Preferred sintered ceramic structures according to the invention can comprise zirconias, titanias, aluminas, silicas, rare earth metal oxides, alkaline oxides, alkaline earth metal oxides and first, second, and third transition series metal oxides and combinations thereof and therebetween. Sintered metal structures can also be provided.

Abstract: Optical communication media particularly adapted for blow-in installation, including single optical fibers and lightweight flexible optical cables comprising one or more glass optical fibers in a multilayer polymer coating, are disclosed. The multilayer coating includes a textured polymer outer layer and at least one soft buffer layer positioned between the textured polymer outer layer and the glass optical fiber or fibers, the buffer layer comprising a low T.sub.g polymer and preferably having a layer thickness at least sufficient to maintain thermally induced microbending loss in the optical communication medium below about 0.5 db/km at medium operating temperatures in the range of 0.degree. C. to -60.degree. C.

Abstract: A glass-ceramic superconductor is disclosed, having a nominal stoichiometric composition consisting essentially of the oxides of Bi, Ca, Sr, Cu and Zn in the stoichiometric formula range: Bi.sub.2 Ca.sub.x Sr.sub.z Zn.sub.n Cu.sub.w O.sub.y, wherein x ranges about 1-2, z ranges about 1-2, n ranges about 0.001-2, w ranges about 1-2, and y ranges about 6-11. These compositions exhibit greatly improved glass stability, yet can yield highly crystalline superconductors which may include large platelet crystals and which can exhibit very low room temperature resistivity.

Abstract: Fiber-reinforced ceramic matrix composite products are made by providing inorganic fiber reinforcement materials with pyrolytic carbon coatings, combining the carbon-coated fibers with a selected ceramic matrix material to make a composite preform, and consolidating the preform with heat and pressure to form the fiber-reinforced composite. Preferably, the peak consolidation temperature of the composite is moderated, with the retained pyrolytic carbon coating acting to preserve tough fracture behavior in the composite product notwithstanding the absence of the conventional graphitic fiber interface layer therefrom.

Abstract: A method for making a fiber-reinforced ceramic matrix composite article is disclosed wherein a ceramic matrix material in the form of a glass powder is combined with a fibrous reinforcing material such as a fiber tow, and the powder and tow are transported into a hot zone wherein they are consolidated together by winding under tension onto a collection mandrel at a temperature above the annealing temperature of the glass. High density composites are provided without the use of subsequent high pressure consolidation treatments.

Abstract: A sealing method and sealed assemblies incorporating novel devitrifiable sealing frits based on thermally crystallizable alkaline earth aluminosilicate glasses, are disclosed. The frits exhibit improved compatibility with refractory composites employed for the fabrication of high temperature fiber-reinforced glass-ceramic assemblies and can be cured at temperatures below those needed to cure prior art sealing compositions to provide strong seals wherein refractory crystal phases selected from the group consisting of anorthite (CaO.Al.sub.2 O.sub.3.2SiO.sub.2), celsian (BaO.Al.sub.2 O.sub.3.2SiO.sub.2), and sanidine, orthoclase or other potash feldspar (K.sub.2 O.Al.sub.2 O.sub.3.6SiO.sub.2) polymorphs constitute the principal phases.

Abstract: Articles with a non-stick coating. An article consisting of a substrate whose surface has --OH groups, and of at least one non-stick polymer layer, said article having also, applied between said substrate and said non-stick polymer layer, a layer which is obtained by making an appropriate bifunctional organo-silane react with a polyamic-acid precursor of polyamide-imide and with --OH groups of the substrate surface, then drying and converting said polyamic-acid into a polyamide-imide by heating at an appropriately high temperature.

Abstract: Ceramic matrix composite articles comprising a ceramic, glass-ceramic or glass matrix and a fiber reinforcement phase disposed within the matrix consisting of amorphous or crystalline inorganic fibers, wherein there is provided, on or in close proximity to the surfaces of the inorganic fibers, a layer of sheet silicate crystals constituting a sheet silicate interface between the inorganic fibers and the ceramic, glass, or glass-ceramic matrix. Optionally, the composition of the matrix may be the same as the sheet silicate interface so that the matrix provides the sheet silicate layer.

Abstract: Silica glass articles of complex shape are provided by a gel machining process wherein a silicate solution is first cast into a mold of simple shape and gelled to a fully crosslinked wet gel body, and the wet gel body is thereafter removed from the mold and machined by grinding, drilling, core drilling, water jet cutting or the like to provide a wet gelled shape of the complex configuration desired. The complex wet gel shape is then dried and consolidated, with no change in configuration (except for shrinkage), to provide a unitary crack-free glass article retaining the shape of the machined gel.

Abstract: UV-curable urethane-acrylate resin systems of improved thermal stability in the cured state are provided, the resins being of polyurethane acrylate, polyurea acrylate, and/or polyurethane/polyurea acrylate composition and being thermally stabilized by the addition of a combination of stabilizers which includes a hindered piperidine derivative and a hindered phenol derivative. The stabilized resin systems, useful for example for the protective coating of glass optical fibers, retain their rapid UV curing characteristics.

Abstract: Ceramic matrix composites and a method for making them are provided, the composites comprising a matrix of an alkaline earth aluminosilicate glass or an alkaline earth aluminosilicate glass-ceramic reinforced with inorganic fibers such as silicon carbide fibers, and the matrix being modified by the incorporation therein of an inorganic particulate additive, the additive being present in a proportion at least effective to increase the interlaminar shear strength, transverse flexural strength, and/or fracture toughness of the composites.