Abstract: Silica glass powders are prepared by mixing a silicic acid ester, water in an amount equal and or larger than 0.5 gram equivalent of an alkoxy group of the silicic acid ester and siliceous particles and dispersing the siliceous particles which have particle sizes larger than 400 .mu.m in an amount of less than 10% by weight and particle sizes of less than 20 .mu.m in an amount of less than 50% by weight and which are dispersed in an amount equal to or larger than 10% by weight of the weight of silica prepared by roasting the silicic acid ester in the same amount as used for the preparation of the mixture, gelling the dispersion to give a gel, drying the gel, and sintering the dried gel. The silica glass powders of high purity are suitable for various uses such as raw materials for the silica glass products for semiconductor industry and for multicomponent glass for optical communication.

Abstract: A method for manufacturing synthetic silica glass by reacting methyl silicate and aqueous ammonia, dispersing the silica particles produced in water, solidifying the silica by the addition of methyl silicate and heating, dehydrating, de-solventing, decarburizing and sintering the solid silica to produce a glass product. The sintered glass may be pulverized to produce a powder. The inventive method is easily carried out and avoids the high energy costs of the prior art. The glass product obtained exhibits excellent high temperature viscosity.

Abstract: A method for producing a uniform glass of a large size without forming bubbles and holes at the bottom thereof is provided. This method comprises concentrating a sol solution obtained by hydrolysis of a metal alkoxide such as alkoxide of silicon in the presence of an organic solvent and ammonia water until a volume of the sol solution reaches 1.00-1.95 times the volume of the charged metal alkoxide, then gelling the concentrated sol solution with addition of a mixed solution of an aqueous catalyst solution and an organic solvent, then drying the gel and heating the dry gel to sinter it.

Abstract: A sacificial fiber method to fabricate straight, curved, or coiled tubes as small as 1 micron (0.000004 inches) in diameter with wall thicknesses starting at less than 0.01 microns. These tubes can be made from many of the materials that can be applied to a surface of carbon, glass, or other tube forming fibers and then made to withstand the environment used to remove the fiber. A monolithic piece can be formed where the tubes are channels or holes.

Abstract: A process for producing porous glass, which comprises preparing a reaction solution containing a metal alkoxide or its oligomer and an organic polymer, hydrolyzing and polymerizing the metal alkoxide or its oligomer in the solution to obtain a gel, and calcining the gel to obtain porous glass, wherein the organic polymer has compatibility with the solution of the metal alkoxide or its oligomer, undergoes phase separation during the hydrolysis-polymerization step and is substantially free from formation of precipitates.

Abstract: The present invention relates to a sol-gel glass producing process which comprises hydrolyzing a metal alkoxide in the presence of an organic solvent and an aqueous ammonia solution to obtain a sol solution, concentrating the sol solution to 1.00-1.95 times the volume of the metal alkoxide used, adding an acid catalyst to the resulting concentrate to allow the concentrate to gel, drying the resulting gel, and heating the dried gel to obtain a desired glass.According to the present invention, a large sized glass can be obtained without the formation of cracks.

Abstract: The invention provides a method for the preparation of synthetic fused silica glass containing a very small amount of hydroxyl groups and has a high viscosity at high temperatures suitable for use as a material of articles for semiconductor processing at high temperatures, such as a crucible for Czochralski single crystal growing of semiconductor silicon. The method comprises hydrolyzing methyl silicate in a medium containing a specified amount of ammonia as a hydrolysis catalyst to form silica particles which are heat-treated in several successive steps.

Abstract: An optical preform is prepared first by depositing soot about a glass subate rod (22) to form a boule. Then the soot boule is sintered to consolidate the material and provide a preform from which optical fiber is drawn. The boule is relatively large so that the resulting preform is capable of providing more optical fiber than those used in the past. In order to be able to sinter successfully the enlarged boule, microwave energy from a furnace (60) is coupled to the glass rod so that the sintering proceeds from the rod radially outwardly thereby allowing gases readily to escape and rendering the process highly efficient.

Abstract: A catalyst for sol-gel methods using metal alkoxide comprises a mineral acid or its anhydride and an organic base, said organic base being a tertiary amine that is substantially insoluble in water and soluble in organic solvents. A sol-gel method using the above-mentioned catalyst comprises a step of hydrolyzing a metal alkoxide with a subsequent polycondensation of hydrolyzate thereof using the catalyst, resulting in a polymer containing gel.

Abstract: A method of manufacturing shaped bodies from ceramic or glass, in which a green body is formed from the starting material for the shaped body in the form of a plastic mass consisting of microdispersed solid particles and water as a dispersing liquid and, if necessary, a binder, after which said green body is dried and sintered, the still wet green body being immersed in water miscible organic liquid having a lower surface tension and a lower enthalphy of vaporization than water, until the water in the green has at least largely been replaced by the organic liquid due to diffusion.

Abstract: A multidirectionally fiber reinforced-glass matrix composite article is disclosed. The fiber reinforcement is precisely oriented in three or more directions to provide high strength and stiffness in each of the three or more directions. A method for making a multidimensionally fiber reinforced glass matrix composite article is also disclosed. The method includes impregnating a fiber preform with a colloidal suspension of inorganic material, cooling the impregnated fiber preform to precipitate the inorganic material, drying the preform, impregnating the preform with heated glass matrix material, and cooling the glass impregnated preform to form the multidirectionally fiber reinforced glass matrix composite article.

Abstract: In a method of manufacturing glass bodies, in which a thixotropic suspension of SiO.sub.2 particles having a diameter in the range from 10 to 500 nm in a dispersing liquid is formed into a green body, after which the green body is purified and sintered, the suspension has a solid:dispersing liquid weight ratio of from 1:1 to 1:1.5, is passed through sieves having an aperture size in the range from 3 to 300 .mu.m under the action of sound or ultrasound, the sieved suspension is then concentrated by pumping off a part of the dispersing liquid under a vacuum and under the influence of sound or ultrasound, such that a solid:dispersing liquid weight ratio of about 1.3:1 is obtained, after which the concentrated suspension is introduced into a mould, heated to a temperature below the boiling point of the dispersing liquid to form a green body. The green body thus obtained is removed from the mould, cooled, and converted to a glass body.

Abstract: Method of and arrangement for manufacturing rotationally symmetrical porous solid bodies.A method of manufacturing rotationally symmetrical porous solid bodies, in which the starting material for the solid body in the form of a suspension consisting of the material for the solid body in solid form and a liquid dispersing agent, is introduced into a hollow mould whose geometry corresponds to that of the solid body to be formed, such that during the introduction of the suspension the hollow mould is rotated about its longitudinal axis, a certain quantity of solid of the suspension being deposited on the inner wall of the hollow mould, and excess residual suspension being removed, after which the green body thus formed is subjected to further process steps to manufacture the solid body, in which process suspension is introduced into the hollow mould in such doses that each time only thin solid layers having a thickness in the range from 10.sup.

Abstract: An improved sol-gel method is proposed for the preparation of a transparent silica gel block, in which a deposit of fine silica particles having a controlled particle diameter as prepared by hydrolyzing an alkoxy silane in the presence of ammonia is dispersed in a silica sol solution prepared in an acidic condition and settled therein to form a structure of closest-packing prior to gelation, drying, sintering and vitrification so that silica glass blocks can be obtained with low volume shrinkage from the wet gel in an improved yield without cracks, bubbles and haziness. The improvement can be further enhanced when two separately prepared deposits of silica particles having larger and smaller particle diameters are dispersed as combined in the silica sol solution, especially, when the particle diameter in one deposit is not exceeding 22.5% of that in the other deposit.

Abstract: Sheets and laminated composites are described which are prepared with epoxy and flocculated vermiculite and mica dispersions. Processes and procedures are also described to obtain film and sheet materials from the flocculated silicate and epoxy dispersions.

Abstract: Aluminosilicate optical glass without boron oxide, comprising 60-95 mols % silica and at least 2 mols alumina, the remainder being made up of at least one oxide of a metal selected from silver and thallium. The glass may also contain caesium. Optical waveguide preforms and methods of making the same are also disclosed.

Abstract: Incorporation of fluorine into a porous silica body, such as an unsintered body produced by a sol-gel method, by VAD or OVPO, reduces or eliminates bubble or pore formation upon re-heating of the glass formed by sintering of the porous material. Effective fluorine concentrations are between 0.01 and 5% by weight. The invention can be used advantageously in producing preforms and optical fiber.

Abstract: In the production of an article of extremely pure synthetic silicon dioxide, wherein silicon tetrachloride is mixed with water to effect hydrolysis, the resulting hydrolysis product is dried, and the resulting dried particulate product is further processed into the desired article, the improvement which comprises employing a ratio of silicon tetrachloride to water so that the hydrolysis product is in the form of a gel, distilling by-product hydrochloric acid out of the gel, preliminarily drying the gel at 100.degree. to 1000.degree. C. to produce an initial product, milling the initial product into a fine granulate at room temperature, separating from the milled granulate a fraction with a particle size of about 40 to 1000 .mu.m, and drying the screened-out granulate fraction while slowly heating to no more than 1400.degree. C. to form the resulting dried particulate product that is further processed into the desired article. As a result, high quality bubble free articles are produced.

Abstract: Compositions for encapsulating electronic components are provided which comprise a blend of a curable resin and an ultra-pure silica filler. The filler is composed of fused silica granules which are prepared from a gel of a silicon-containing organic compound, such as TEOS, and which have a uranium content of less than about 0.1 parts per billion and a thorium content of less than about 0.5 parts per billion. The compositions can be readily manufactured in commercial quantities at reasonable costs and are particular well-suite for encapsulating components, such as, high density RAMs, which are sensitive to alpha particles.

Abstract: In one embodiment this invention provides novel microporous inorganic oxide glass monolith structures, which have improved mechanical strength and optical transparency. An invention glass monolith is produced by a novel sol-gel process, which utilizes trioxane as an essential additive during the gellation phase, to provide a glass monolith with micropores having uniformity of size and shape.

Abstract: In a forming a silica glass at low temperature, a fumed silica is added to a hydrolyzed solution of a metal alcoxide. 0.2-5 mol of fumed silica is added to 1 mol of metal alcoxide. Being uniformly dispersed, the solution is gelled and dried to be dry gel and then sintered to be non-porous. This process allows a practically large sized silica glass to be materialized which has been impossible by the previous sol-gel technology. In addition, a further large silica glass can be prepared by adjusting pH value to 3-6 with addition of base in the sol solution.

Abstract: A silicate optical glass article is made by forming a gel from a hydrolyzed silicon alkoxide. The resulting gel is molded, cured, dried, solvents removed, heated to form a dense glass having near net shape dimensions thereby reducing expensive polishing steps to obtain the desired final dimensions and surface quality.

Abstract: The disclosed simple, economical and rapid sol-gel process for forming a silica-based glass body, termed the "vapogel" process, comprises introduction of a silicon halide-containing gas (e.g., SiCl.sub.4 +O.sub.2) into an aqueous medium. The thus formed sol can gel within minutes, resulting in a monolithic gel from which particles having a narrow size distribution can easily be formed. The thus formed particles can be used to produce a glass body such as an optical fiber. Various techniques for forming the glass body from the gel are disclosed. Among the many advantages of the vapogel method are its ability to produce very homogeneous mixed oxide glasses of composition not obtainable by prior art sol-gel processes, and the advantageous mechanical properties of the gel produced by the method. The latter makes possible, inter alia, formation of particles having a relatively narrow size distribution.

Abstract: A spherical silica glass powder particle having projections of network pattern on its surface is produced by gel-route formation.

Abstract: In one embodiment this invention provides a novel sol-gel process for the production of microporous inorganic oxide glass monolith structures which have improved mechanical strength and optical transparency. An essential feature of the process is the use of trioxane during the gellation phase, to provide a glass monolith with micropores which have uniformity of size and shape.

Abstract: By hydrolyzing an organoalkoysilane monomer at high concentration in solution to form a silanol, allowing the silanol to age to produce a low molecular weight oligomer, spin-applying the oligomer onto a substrate to form a discrete film of highly associated cyclic oligomer thereon, heat treating the oligomer film to form a modified ladder-type silsesquioxane condensation polymer, and then oxidizing the silsesquioxane in an O.sub.2 RIE, an organoglass is formed which presents novel etch properties. The organoglass can be used as an etch-stop layer in a passivation process.

Abstract: Incorporation of fluorine into a porous silica body, such as an unsintered body produced by a sol-gel method, by VAD or OVPO, reduces or eliminates bubble or pore formation upon re-heating of the glass formed by sintering of the porous material. Effective fluorine concentrations are between 0.01 and 5% by weight. The invention can be used advantageously in producing preforms and optical fiber.

Abstract: A method of and arrangements for manufacturing glass bodies, in which method a thixotropic suspension, being the starting material for the glass body, is used to form a porous green body which is subsequently subjected to a purification step in a heated gaseous phase and then sintered to form a glass body, the starting material being homogenized and liquefied in a closed elastic mould by subjecting it to sound or ultrasonic, after which the liquid starting material is given the shape of the glass body to be formed and then solidified.

Abstract: A method of and arrangements for manufacturing glass bodies, in which the starting material for the glass body, being an anhydrous suspension having a microdispersed solids content, is used to form a porous green body which is subsequently purified and sintered, in which by separating the phases of an anhydrous suspension the green body is formed by means of electrophoresis on a deposition electrode whose shape corresponds to that of the glass body to be produced.

Abstract: Method and equipment for the manufacture of glass bodies wherein a porous green body is formed by extrusion from the starting material for the glass body in the form of a plastic mass and this green body is then purified and sintered, the plastic mass being transformed into a state of reduced viscosity by the application of mechanical forces utilizing the thixotropic effect and being extruded in this state.

Abstract: Method and equipment for the manufacture of glass bodies in which a porous green body is formed from the starting material for the glass body in the form of a thixotropic suspension, is dried, purified and then sintered, during which process the starting material is transformed into a state with minimum viscosity and homogenized by the introduction of mechanical forces, is poured in the low-viscosity state into a mould of hydrophobic material corresponding to the shape of the glass body to be manufactured and is dried in the mould until a shrinkage of approximately 10% is achieved and then, after removal from the mould, is subjected to further processing steps to produce the glass body.

Abstract: A method of and arrangements for manufacturing glass bodies, in which the starting material for the glass body, being a suspension having a microdispersed solids content, is used to form a porous green body which is subsequently purified and sintered, in which, by separating the phases of the suspension in an arrangement in which a pressure difference can be built up, the green body is deposited on a porous membrane whose shape corresponds to that of the glass body to be produced, the pores of the membrane having a diameter in the range from 1 to 500 times the average particle diameter of the solids content of the suspension.

Abstract: Method and equipment for the manufacture of glass bodies wherein a porous green body is formed by extrusion from the starting material for the glass body in the form of a thixotropic suspension and this green body is then purified and sintered, during which process the starting material is brought in a state of minimum viscosity into an extruding press closed at its outlet end, is heated in the extruding press to a temperature below the boiling point of the dispersing liquid and then, after the extruding press is opened, is extruded into a green body of dimensionally stable shape by means of the die of the extruding press.

Abstract: A method of manufacturing glass bodies, in which the starting material for the glass body, in the form of microdispersed SiO.sub.2 particles, is used to form an open-pore green body which is subjected to a cyclic purification process in which the impurities present in the green body react with a purifying gas which is heated to a temperature in the range from 600.degree. to 900.degree. C., after which the green body is sintered; in each cycle of the said process, the arrangement holding the green body to be purified being flushed and subsequently evacuated.

Abstract: A silicate optical glass article is made by forming a gel from a hydrolyzed silicon alkoxide. The resulting gel is molded, cured, dried, solvents removed, heated to form a dense glass having near net shape dimensions thereby reducing expensive polishing steps to obtain the desired final dimensions and surface quality.