Abstract: A method is taught for the preparation of mixed metal oxide sols particularly suited for the deposition of protective mixed metal oxide coatings upon a substrate.

Abstract: Carriers comprising silica-based glass providing for the controlled release of biologically active molecules, their methods of preparation, and methods of use are disclosed. The carriers are prepared using a sol-gel-derived process. Biologically active molecules are incorporated within the matrix of the glass during production.

Abstract: SiO.sub.2 aerogels containing carbon particles are obtainable by heatinga) organically modified SiO.sub.2 aerogels in the presence of at least one pyrolyzable hydrocarbon gas and/or at least one inert gas orb) organically unmodified SiO.sub.2 aerogels in the presence of at least one pyrolyzable hydrocarbon gas and in the presence or absence of inert gases to 600.degree.-1300.degree. C.

Abstract: A microwave-absorbing material composed of blends of polar icosahedral molecular units with a variety of host matrices, or with polymers with the units covalently bonded in a pendant manner to the polymer chain. Both blends and polymers must impart a high degree of orientational mobility to the units so that they can absorb microwave radiation. These materials employ orientationally mobile, polar icosahedral molecular units as the source of dielectric loss at microwave frequencies. Examples of these units are the polar carboranes (ortho- and meta-carborane), polar carboranes with electronegative and/or electropositive substitutes, and polar "buckminsterfullerenes.

Abstract: A fine silica tube composed of silica gel and having an outer diameter of 0.05 to 2 .mu.m wherein the cylindrical wall portion of the tube has a cross-section defined by a substantially square outer periphery and a substantially square vacant center, or by a circular outer periphery and a substantially square vacant center; and a fine silica tube composed of silica glass and having an outer diameter of 0.05 to 1.4 .mu.m wherein the cylindrical wall portion of the tube has a cross-section defined by a substantially square outer periphery and a substantially square vacant center. The fine silica gel tube is made by treating a tetraalkoxysilane with ammonia or aqueous ammonia in a water-soluble alcohol medium in the presence of tartaric acid, citric acid, a tartaric acid salt or a citric acid salt, whereby the tetraalkoxysilane is hydrolyzed. The fine silica glass tube is made by calcining the fine silica gel tube at 800.degree. to 1,400.degree. C.

Abstract: This invention provides an extremely porous xerogel dried at vacuum-to-below supercritical pressures but having the properties of aerogels which are typically dried at supercritical pressures. This is done by reacting the internal pore surface of the wet gel with organic substances in order to change the contact angle of the fluid meniscus in the pores during drying. Shrinkage of the gel (which is normally prevented by use of high autoclave pressures, such that the pore fluid is at temperature and pressure above its critical values) is avoided even at vacuum or ambient pressures.

Abstract: Glassy coatings are made by curing in situ a coating of a sol gel of boron triethoxide, water, alcohol, and the alkoxides of: titanium and zirconium. A platey filler such as mica is present. The coating may be applied to teeth as a dental fissure sealant or varnish to protect restorations, or as an inherently coloured cosmetic coating, or as a prophylactic coating.

Abstract: A process for making inorganic gels by reaction of tetraalkoxy orthosilicates, tetraalkoxy titanates and tetraalkoxy zirconates with strong carboxylic acids. Water need not be present initially as a reactant. Optically clear, very small pore size, narrow pore size distribution, and high specific area inorganic gels useful for abrasion-resistant coatings, optical applications, catalyst or enzyme support, gas separation, or chromatography packing are thus produced.

Abstract: An electrorheological fluid that includes a dispersed particulate phase of anhydrous amorphous ceramic particles. The anhydrous amorphous ceramic particles can be of a very precisely tailored composition that is unavailable in crystalline form, for obtaining enhanced electrorheological response. The amorphous particles are substantially free of water when used, and have reduced tendency to absorb water in use. Accordingly, the electrorheological fluid containing anhydrous amorphous electrorheologically responsive ceramic particles has wide applicability for use, and enhanced durability in such use.

Abstract: This invention relates to a process for the preparation of lithium aluminosilicate or gamma lithium aluminate ceramics having a controlled microstructure and stoichiometry.According to this process, mixing takes place accompanied by stirring in a short chain anhydrous alcohol of an unpolymerized liquid aluminium alkoxide and optionally a silicon alkoxide with a hydrated or unhydrated lithium hydroxide, followed by the addition of water in order to hydrolyze the mixture and obtain, after drying, beta LiAlO.sub.2 powder.This powder can be directly compacted and then sintered at temperatures of 800.degree. to 1150.degree. C. without prior calcination giving a gamma lithium aluminate ceramic with a controlled stoichiometry and microstructure (grains of 0.1 to 10 .mu.m).

Abstract: A La.sub.1-x Sr.sub.x Cr.sub.1-y Mn.sub.y O.sub.3 ceramic oxide gel obtainable by the process comprising the steps of:(a) providing a colloidal solution of polyhydroxy organic chelating agents selected from the group consisting of ethylene glycol and citric acid and metal salts selected from the group consisting of lanthanum, strontium, chromium, and manganese, each salt being present in an amount necessary to provide the stoichiometric amount of metal ions required in the ceramic oxide gel;(b) heating the colloidal solution to hydrolyze and polymerize the metal ions in the solution to a mixed metal oxide precursor of the ceramic oxide gel; and(c) adding organic acid, water or both to the precursor of the ceramic oxide gel to peptize the metal ions; and(d) heating the peptized precursor to evaporate solvent to form a thick, viscous, flexible, ductile, handleable gel that can be cast, extruded, or drawn; wherein x and y are independently 0 or 1.

Abstract: An alumina based ceramic fiber having submicron sized alpha alumina crystals and a density of at least 95% theoretical is obtained from a sol-gel process.

Abstract: An improved method for preparing low-concentration polysilicate microgels from a water soluble silicate and a strong acid in which the silicate and acid are mixed at a rate to produce a Reynolds number of at least 4000, the mixture is aged and then diluted to a silica concentration of not more than 1.0 wt. %. The method achieves reduced silica deposition during the preparation of the microgels.

Abstract: A method for producing a highly loaded, aqueous suspension having a pourable viscosity and containing from 20 to 50 volume percent colloidal ceramic or metal particles. A biologically produced polymer dispersant having a high density of carboxyl functional groups and an average molecular weight of at least 1,000 is solubilized in water in a quantity of less than 1.0 percent dry weight basis of particles. The ceramic or metal particles are then introduced to the solution, and agitated to form a substantially nonagglomerated suspension. The polymer dispersant may be produced by a bacterium grown in situ with the particles. A biologically produced polymer gelling agent that is miscible with the polymer dispersant may be admixed into the suspension, which is then maintained in a nongelled state while being supplied to a mold. The suspension is then exposed to a gel-triggering condition to form a gelled, sinterable article.

Abstract: Proposed is a liquid coating composition for the formation of a siliceous coating film having good storage stability against gelation for the protection, levelling or electric insulation of various substrate surfaces. The composition is a uniform solution comprising:(A) a partial cohydrolysis-cocondensation product of(a) a first hydrolyzable silane compound represented by the general formulaHSi(OR).sub.3,in which each R is, independently from the others, an alkyl group having 1 to 4 carbon atoms or a phenyl group, and(b) a second hydrolyzable silane compound represented by the general formulaSi(OR).sub.4,in which each R has the same meaning as defined above, in a molar ratio of (a):(b) in the range from 1:9 to 9:1; and (B) an organic solvent to dissolve the component (A). The storage stability of the coating composition can be improved by removing the alcohol contained therein as the hydrolysis product of the silane compounds to such a content as not to exceed 15% by weight.

Abstract: The present invention relates to a process for nuclear waste disposal. In it, a glass forming mixture including an aqueous solution of one or more metal alkoxides, alcohol, and solubilized, low level radioactive waste having a pH effective to hydrolyze the one or more metal alkoxides is formed. The one or more metal alkoxides in the glass forming mixture are converted to a network of corresponding one or more metal oxides. A gel is then formed from the glass forming mixture containing the network of one or more metal oxides. The gel is dried and sintered under conditions effective to form a densified glass.

Abstract: Hollow microspheres of ceramic material are formed by a sol-gel technique involving forming and stabilizing an emulsion of an aqueous sol of the ceramic material in an organic phase, followed by dehydration of the stabilized emulsion droplets by extraction using a water-absorbing organic liquid, to form hollow gelled spheres, and finally recovery, drying and calcination of the spheres to the final product. The separation of the emulsion formation and dehydration steps into two distinct stages results in the ultimate formation of microspheres with improved uniformity and size distribution.

Abstract: A process for synthesizing amorphous silica microspheres having fluorescence behavior includes the steps of placing into a container an organosilicon precursorand with a highly acidic solution and rinsing with a solvate to remove excess of the organosilicon precursor from the amorphous silica microspheres. The organosilicon precursor and the highly acidic solution are immiscible. The process for synthesizing amorphous silica microspheres also includes the steps adding a dopant from a group consisting of rhodamine-6G, rhodamine-B, europium 3.sup.+, fluorescein, coumarin-120, coumarin-314T, thionine, uranium and uranium-sensitized europium, stirring the organosilicon precursor and the highly acidic solution to form droplets of the organosilicon precursor in the highly acidic solution whereby water in the highly acidic solution hydrolizes the droplets of the organosilicon precursor to form amorphous silica microspheres and rinsing with a solvant to remove excess of the organosilicon precursor therefrom.

Abstract: There is disclosed doped spin-on glass compositions such as boronoxide doped spin-on glass compositions with a high carbon content and silane adhesion promoter incorporated therein for use as coating layers on substrates such as silicon wafers.

Abstract: Method for introducing boron into dry, porous gels obtained by means of the "sol-gel" technique, consisting of contacting the concerned gel with a boron compound obtained in situ by causing suitable reactants in gas state to react with one another.

Abstract: Carbon-containing black glass compositions of matter having the empirical formula SiC.sub.x O.sub.

Abstract: A sol-gel process of producing durable alpha alumina-based ceramic particularly useful as abrasive grain from alpha alumina monohydrate is improved by the addition of a nucleating agent. Improved abrasive products containing the durable ceramic abrasive grains are also provided.

Abstract: The sol-gel process for forming dense alumina based cermics or dense ceramics with alumina as a sintering additive, the process comprising the steps of: preparing polymeric alumina sol by hydrolysis of Al (O--iBu)3 with a strong acid; preparing the ceramic dispersion in the alumina sol; gelling the dispersion; drying the gel dispersion to form a solid; calcining the solid; and sintering the calcined solid.

Abstract: A method for manufacturing a glass is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing at least one compound selected from the group consisting of an acid, an ammonium salt and an alkylammonium salt to precipitate the metal salt as microcrystals in the pore. Also, a method for manufacturing a glass for use as a gradient index optical element is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing a salt of a metal component different from the above-mentioned at least one component and at least one compound selected from the group consisting of an acid and a salt to provide the metal components with concentration distributions.

Abstract: A nonlinear optical material which exhibits large third order nonlinear optical susceptibilities, and responds to light with wavelengths different from each other for multiple signal processing, and methods of manufacturing the same. This is accomplished by dispersing a high concentration of a metal fine particle and/or a semiconductor fine particle different in absorption wavelength throughout an optically transparent matrix such as a glass, a ceramic or a polymer.

Abstract: Al.sub.2 O.sub.3 -Er.sub.2 O.sub.3 ceramic abrasive grains comprising a second phase consisting of aluminum oxides and erbium oxides in the form of reaction products surrounding a first phase and the first phase exclusive of the second phase and substantially consisting of alpha alumina only, the size of the crystal grain consisting of two phases being below 1 micron, which are obtained by a sol-gel process wherein erbium precursor is incorporated before sintering in an amount of 0.05-0.4 wt % in a form of Er.sub.2 O.sub.3, which is suitable for lapping composition, grinding wheel, grinding disc and coated abrasive articles.

Abstract: Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

Abstract: .beta.-Al.sub.2 TiO.sub.5 protective coatings have been developed for both dense and porous ceramics such as SiC and Si.sub.3 N.sub.4 using a chemical solution processing method involving the hydrolysis and condensation of aluminum tri-sec butoxide and titanium butoxide. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates required for crack-free .beta.-Al.sub.2 TiO.sub.5 are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline .beta.-Al.sub.2 TiO.sub.5 is achieved by a succession of calcination below 450.degree. C. and a final heat-treatment at 1300.degree. C. for ten hours with controlled heating and cooling rates.

Abstract: A process is provided for preparing ceramics which can be produced into any predetermined shape by way of gel precursors.

Abstract: The invention relates to a metal oxide film formed on a glass substrate by a sol-gel process. To make the metal oxide film minutely rough, at least two sols are respectively prepared from at least one compound selected from the group consisting of metal alkoxides and metal acetylacetonates, such that polymers of the sols have different average molecular weights. Then, the at least two sols are mixed with a solvent so as to prepare a coating solution. The coating solution is applied to the glass substrate so as to form thereon a sol film. The thus coated glass substrate is heated so as to transform the sol film into a gel film and to form thereon numerous micro-pits.

Abstract: A reticulated ceramic product is provided having from about 5 to about 95 percent, preferably from about 10 to about 90, percent of the total porosity attributable to mesopores. Reticulated ceramic products provided include silicon oxide, aluminum oxide, zirconium oxide and ruthenium oxide. Reticulated ceramic products are prepared using a porous solid matrix as a template. The reticulated ceramic products are useful as chromatographic media, catalysts and adsorbents.

Abstract: Method is provided for preparing PbO-based ceramics by mixing metal cations in alkanolamines and then adding the mixture to lead carboxylates in alcohol, to obtain ceramic solutions or gels therefrom. The metal cations are sourced from metal alkoxides, chelates and salts and include metals of Ti, Zr and La. The above solutions and gels can be employed to form PbO-based powders, fibers and films, e.g. films of PZT and PLZT, which find electrical and optical applications such as ferroelectric memory and dielectric waveguides. The invention resides in the above method and resulting PbO ceramics which have e.g. films of considerably higher dielectric constants than previously known in the art.

Abstract: An inhomogeneous broadband absorber of electromagnetic energy constructed from an aerogel-lossy dielectric composite, where the concentration of the lossy dielectric increase across its thickness such that the composite's dielectric properties vary from those of the aerogel to those of the lossy dielectric. Materials useful for serving as the lossy dielectric include polar molecules, polar icosahedral molecules, polyaniline electron-conducting polymers, and polyprrole electron-conducting polymers. Another inhomogeneous layer absorber is constructed from an aerogel that is intrinsically a lossy dielectric. The variation in dielectric properties is achieved by increasing the density of the aerogel across the thickness of the material. Aerogel materials for such an absorber include organic aerogels which have been pyrolized in an inert atmosphere to give vitreous carbon aerogels. Methods for fabricating these absorbers are described.

Abstract: The present invention relates to synthetic phyllosilicates having a lamellar structure of the type T--O--T devoid of OH.sup.- and F.sup.- ions. Said phyllosilicates are very resistant to oxidation and possess a high thermal stability. The invention further relates to a process for the preparation of said phyllosilicates.

Abstract: Ceramic yttrium aluminate fibers are produced by processes that result in the formation of a microcrystalline ceramic oxide structure. In one process, a stoichiometric amount of a yttrium alkoxide is mixed with an aluminum alkoxide to produce a homogeneous mixture in an alcohol solvent. Following the addition of an alkoxide precursor of ZrO.sub.2 or of HfO.sub.2, the optional addition of an alkoxide precursor of MgO, and the subsequent addition of an organic acid, hydrolytic condensation to produce a suitable sol is accomplished by adding water. A slight excess of yttrium alkoxide can be used instead of the MgO precursor. The viscosity of the sol is adjusted to form a tractable gel that is spun into fibers which, after curing and firing, are shown to be microcrystalline in form, the resulting fibers having a submicron average grain size. Strength and stability result from the presence of solid particles of partially stabilized zirconia or hafnia at the grain boundaries and the triple points.

Abstract: This invention describes a method of manufacturing silica waveguide optical components in which silica glass films are laminated on a substrate by repeating a unit operation in which a sol material, a precursor of glass particles, is coated and then the coated layer is heated in an oxygen atmosphere. wherein the heating temperature is controlled in such a manner that the radius of curvature of warping of the substrate is 2 m or more after the coated layer is heated, thereby preventing cracking in the formed silica glass film and/or peeling of the coated layer. At locations where a difference in height is present, at least when sol is coated first time, the thickness of the coated layer is less than that of one of the subsequent coated layers.

Abstract: A carbon-containing black glass has the empirical formula SiC.sub.x O.sub.y wherein x ranges from about 0.5 to about 2.0 and y ranges from about 0.5 to about 3.0 and is resistant to oxidation up to a temperature of about 1400.degree. C. The black glass is synthesized by heating a spirosiloxane polymer in a non-oxidizing atmosphere up to a temperature in the range of from about 750.degree. C. to about 1400.degree. C. The polymers are synthesized by reacting the spirosiloxane oligomers: ##STR1## wherein a and b are integers from 0 to 20, preferably 1 to 5, c and d are integers from 2 to 20, preferably 2 to 6, m is an integer from 0 to 10, preferably 0 to 4, and wherein for each silicon atom in the oligomer having R and R' moieties, R is independently selected from the group consisting of alkyl groups from C.sub.1 to C.sub.20, preferably C.sub.1 to C.sub.5, and R' is independently selected from the group consisting of hydrogen, and alkenyl groups from C.sub.2 to C.sub.20, preferably from C.sub.2 to C.sub.5.

Abstract: Process for preparing a high temperature superconductor such as yttrium bum copper oxides, by dissolving suitable proportions of hydrolyzable salts, oxides, or organometallic compounds of yttrium, barium and copper in an acid pH-controlled water-containing organic solvent such as methanol, and subjecting the resulting solution to ultrasonic energy or to an oxidation-reduction reaction, preferably while passing oxygen under a positive pressure through the solution, and precipitating a hydrolyzed precursor material. Such precursor material is then heated or annealed at temperatures between about 300.degree. C. and about 600.degree. C., also preferably in the presence of flowing oxygen, to produce the desired high temperature superconductor material.

Abstract: A method of producing uniform inorganic microspheres with a particle size of 0.01 to 500 .mu.m by injecting an aqueous solution containing a particle-forming material into an organic solvent. The method includes injecting the aqueous solution into the organic solvent through a macromolecular membrane having a hydrophobic surface and having pores substantially uniform in pore size and extending in the direction of thickness of the membrane, substantially straight through the membrane, so that a path length of each of the pores corresponds substantially to a thickness of the membrane, to form, in said organic solvent, a large number of emulsion particles substantially uniform in size and then producing uniform inorganic microspheres from said emulsion particles on a one emulsion particle-to-one microsphere basis. The pores in the membrane are formed by either a corpuscular or laser beam.

Abstract: A method of making metal oxide clusters in a single stage by reacting a metal oxide with a substoichiometric amount of an acid in the presence of an oxide particle growth terminator and solubilizer. A method of making a ceramer is also disclosed in which the metal oxide clusters are reacted with a functionalized polymer. The resultant metal oxide clusters and ceramers are also disclosed.

Abstract: A composite substrate is provided, which comprises a cordierite-anorthite-boron base composite material and has a microstructure with anorthite included in the cordierite phase. This substrate can be used in the form of a circuit substrate, because it has high-enough mechanical strength, a coefficient of thermal expansion close to that of silicon and a decreased dielectric constant and, moreover, can be sintered at a low temperature.

Abstract: The distributed index of refraction type optical element consists of an element composing a glass forming oxide and a cation composing a glass modifying oxide, and has therein a distributed index of refraction imparted by a gradient of density of the element and a distributed index of refraction imparted by a gradient of density of the cation which are completely independent of each other. This optical element permits controlling chromatic aberration in various ways and has various favorable optical characteristics. The method of making the optical element comprises a first step for imparting a first distributed index of refraction to a glass body material by forming a gradient of density of the element and a second step for imparting a second distributed index of refraction to the glass body material by forming a gradient of density of the cation.

Abstract: A method for fabricating Y.sub.3 Al.sub.5 O.sub.12 (YAG) fibers from water soluble polymers includes a pre-YAG polymer synthesis, with solution viscosity adjustment followed by fiber spinning and heat treatment. The polymer synthesis employs polar solvents such as water or alcohol with a carboxylic acid containing at least two carboxyl groups.

Abstract: This invention provides a continuous ceramic oxide fiber comprising Al, Y, and O. In another aspect, a method of making the same is taught. The continuous ceramic oxide fiber is useful, for example, as thermal insulation, as a filter component, and as a reinforcement for structural composites.

Abstract: The present invention relates to a process for the synthesis of fluoride glass by the sol-gel method.The object of the invention is to synthesize an impurity-free fluoride glass.This object is achieved with the aid of a process having stages consisting of preparing a wet oxygenated gel from precursors containing all the cations constituting said fluoride glass, hydrolyzing said gel, drying said gel and in which the process is characterized in that it also comprises the stage consisting of treating said oxygenated gel by a fluorinating agent in the vapour phase, at a temperature below the glass crystallization point.This process more particularly makes it possible to produce fluoride glass for optical fibres.

Abstract: Carbon-containing black glass compositions of matter having the empirical formula SiC.sub.x O.sub.y and derived from the precursor polymers obtained by reacting (a) cyclo siloxanes and (b) non-cyclic siloxanes, each of the reactants having either or both of hydrogen and an unsubstituted vinyl group whereby a polymer is formed by a hydrosilylation reaction.

Abstract: A process is disclosed for the production of high purity mullites. The process involves reacting a mixture of aluminum alkoxide and silicon alkoxide with an atomic ratio (weight) of Al/Si in the range of 2-7 in an aromatic hydrocarbon solvent at a temperature of 200.degree.-350.degree. C. and calcining the resulting reaction product at a temperature above 900.degree. C. The mullite product obtained finds wide application as a high temperature service structural material such as for automotive engines and turbines as well as a support for combustion catalyst.

Abstract: This invention relates to structural aggregate pigment products that are cationic, and have improved wet-end retention. A method for converting anionic pigments to cationic pigments is also provided. More particularly, a structural aggregate pigment comprising a clay and/or titanium dioxide or other particulate components, and a functional microgel made from silicon and aluminum or zinc gel formers and a gelling agent such as calcium chloride, can be cationized by adding an effective amount of modified or unmodified epichlorhydrin dimethylamine condensate to a slurry of the structured pigment. The resulting cationic pigments have superior papermaking characteristics and a much improved retention.

Abstract: An alkoxysilane sol-gel composition and method for its production are disclosed whereby an alkoxysilane of the general formulaSi(OR).sub.4wherein R is an organic radical such as methyl, ethyl, propyl or butyl is hydrolyzed with an acid catalyst and the resulting acidic sol is further hydrolyzed and condensed in the presence of an alkaline component which accelerates gelation to form an inorganic oxide network.

Abstract: Ceramic beads having a bimodal pore distribution are prepared by a process involving a) formation of a ceramic particle slurry, b) adding a foamable prepolymer to the slurry to form a mixture, c) dispersing the mixture as beads in a second liquid, d) polymerizing and foaming the prepolymer, e) recovering the beads and firing them to remove the polymer and bond the ceramic particles. The beads can optionally be joined by sintering. Beads with a monodal pore distribution can be made by using a nonfoaming prepolymer.