Abstract: The invention includes environmentally stable athermalized optical fiber gratings and methods of making such stabilized optical waveguide fiber grating. Stable humidity-resistant athermalized fiber Bragg gratings are provided by stabilizing a negative thermal expansion substrate and utilizing a durable frit to attach the fiber Bragg grating to the substrate.

Abstract: An athermal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: The invention includes methods of stabilizing negative thermal expansion glass-ceramic optical waveguide substrates. The invention includes the stabilized negative thermal expansion glass-ceramic optical waveguide substrates. The stabilized substrates have very stable physical characteristics such as dimensional length when exposed to extreme environments. The stabilized substrates are used to athermalize optical waveguide devices such as optical fiber grating. The stabilized substrates are particularly well suited for providing athermalized fiber Bragg grating.

Abstract: An athernal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: A hybrid CMC laminate is comprised of alternating layers of dense ceramics and fiber reinforced CMCs. The strategy involves the use of strong and stiff ceramics in order to delay the onset of cracking within the CMC layers. To provide protection from mechanical abrasion, improve thermal conductivity and inhibit oxygen ingress into the CMC layer, ceramic layers are placed on the outer surfaces of laminate. The laminate is produced by stacking alternating layers of dense ceramic and binderless layers of fiber reinforced CMCs, and then hot-pressing them together. The volume fractions of the constituent layers and the fiber architecture can be readily varied through this process. Reinforcement architecture (unidirectional vs. crossply) and the relative volume fractions of the phases effects the tensile and flexural properties of the laminates.

Abstract: An athermal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: Beta-spodumene bodies and method of preparing the bodies that involves providing a uniform plastic batch of inorganic raw materials, organic binder, and vehicle, wherein the inorganic raw materials are composed of, in percent by weight, about 75% to 95% minerals, and about 5% to 25% glass. The batch is formed into a green body that is fired to produce a body composed substantially of beta-spodumene, and having a thermal expansion coefficient of <10.times.10.sup.-7 /.degree.C.(0-800.degree. C.), and a strength of .gtoreq.4 Ksi.

Abstract: The invention relates to fiber reinforced composite materials, and a method for making, in which ceramic, glass-ceramic or glass matrix precursor particles are coated with a layer of sheet silicate crystals, or precursors for sheet silicate crystals, and then combined with a fiber reinforcement phase disposed within the matrix consisting of amorphous or crystalline inorganic fibers. The method results in a composite material in which a substantially continuous layer of sheet silicate is provided on the matrix particles, resulting in a substantially continuous sheet silicate interface between the inorganic fibers and the ceramic, glass or glass-ceramic matrix.

Abstract: This invention is directed to the fabrication of SiC fiber reinforced, ceramic matrix composite articles exhibiting superior high temperature oxidative stability, those articles comprising:(a) a glass-ceramic matrix wherein alkali metal and/or alkaline earth metal aluminosilicate crystals constitute the predominant crystal phase;(b) a fiber reinforcing phase comprising SiC fibers coated with an alkali metal and/or alkaline earth metal sheet silicate entrained within said glass-ceramic matrix; and(c) a borosilicate glass phase dispersed as an intergranular glass within said glass-ceramic matrix, said borosilicate glass phase generally being present in an amount sufficient to provide an intergranular glass phase therein.

Abstract: Inorganic reinforcing fibers comprising hybrid BN--C protective coatings containing up to 12% by weight of hexagonal (graphitic) carbon dissolved in the BN matrix but being essentially free of undissolved pyrolytic and graphitic carbon secondary phases, and fiber-reinforced ceramic matrix composite products incorporating the protectively-coated fibers, are disclosed. The fibers resist oxidation and provide good bonding interface characteristics when disposed in ceramic encapsulating materials, such that the composite products exhibit excellent resistance to high temperature embrittlement.

Abstract: There is disclosed a fiber-reinforced composite having a high degree of fracture toughness and being composed of a glass-ceramic matrix reinforced with silicon carbide or graphite type fibers, the predominant crystal phase of the matrix glass-ceramic being canasite, and/or agrellite, and/or fedorite.

Abstract: Silicon nitride reinforcing fibers provided with a protective surface coating comprising a boron nitride base layer and, optionally, an alumina overcoating, and fiber-reinforced ceramic matrix composite products incorporating the protectively-coated fibers, are disclosed. The composites offer significantly improved high temperature strength in combination with low dielectric constant and low dielectric loss characteristics.

Abstract: Fiber-reinforced ceramic matrix composite products comprising boron-nitride-coated reinforcing silicon carbide fibers disposed in a substantially non-porous alkaline earth aluminosilicate glass-ceramic matrix are disclosed, the matrix comprising triclinic anorthite (CaO,SrO.Al.sub.2 O.sub.3.2SiO.sub.2) as the principal crystal phase and the products exhibiting unexpectedly good resistance to high-temperature degradation.

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: 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: 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: 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: 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 cyrstalline 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: The present invention is directed to the preparation of hybrid composite bodies composed of an essentially alkali-free, alkaline earth aluminosilicate glass matrix reinforced with SiC whiskers and continuous ceramic fibers.

Abstract: This invention relates to the production of laminated structures consisting essentially of a light weight interior member prepared from a glass, glass-ceramic, or ceramic, an exterior member prepared from a glass, glass-ceramic, or ceramic, and a bonding member prepared from a glass, glass-ceramic, or ceramic. The light weight interior member may be composed of a porous body, a corrugated body, or a honeycomb body. In a preferred embodiment, at least one of said members is reinforced through the entrainment of ceramic fibers and/ or whiskers. In the most preferred embodiment, each exterior and interior member is reinforced through the entrainment of ceramic fibers and/or whiskers and the bonding member is reinforced through the entrainment of ceramic whiskers.