Abstract: Lowered cost fabrication including preparation of large bodies of void-free, high-silica glass, depends upon gellation of an aqueous sol of colloidal silica particles, followed by drying and firing of such gel. Freedom from cracks in the dried gel is the consequence of included polymeric material which wets the particles. The polymeric material is removed by thermal decomposition attended upon temperature attained in firing.

Abstract: A method of manufacturing gradient index optical element comprises preparing a sol using silicon alkoxide and a metal alkoxide as a dopant source of index-modifying cations. The sol is treated to obtain a wet gel. Metal alkoxide from the wet gel is eluted by immersing the wet gel in a solvent to produce a concentration gradiation of the metal alkoxide in the wet gel, and the wet gel is then washed. The steps of eluting and washing are repeated so that a gradient index optical element is produced having a large difference in refractive index between the outer periphery portion and the center of the gel.

Abstract: A method for preparing a silica glass article of improved purity is provided. The article is prepared by a sol-gel method and is then heat treated to a selected temperature between about 1500.degree. and 2200.degree. C. and maintained at the selected temperature for a predetermined period of time sufficient to remove silica crystals, inclusions, microcracks and bubbles. The resulting silica glass articles have improved purity and can be used as photomask substrates or as preforms for optical fibers.

Abstract: A process for preparing an oxidation resistant black glass having the empirical formula SiC.sub.x O.sub.y, wherein 0<x.ltoreq.2.0 and 0<y.ltoreq.2.2. The process comprises reacting cyclosiloxane monomers to effect the bonding of one vinyl carbon atom to a silicon, curing the product at not greater than 250.degree. C., and pyrolyzing at about 800.degree.-1400.degree. C. in an atmosphere containing a sufficient amount of oxygen to reduce the carbon content of the black glass to a desired level.

Abstract: An improved method for the fabrication of lightweight ceramic matrix composite panels, utilizing pressure forming with floating tooling to shape integral stiffeners such as raised integral surface channels on panel surfaces. The consolidation of green composite material against refractory floating tools by hot hydrostatic or isostatic (gas) pressing, followed by removal of the tooling, yields a strong, rigid, yet lightweight ceramic structure.

Abstract: In order to prepare particles of a vitreous enamel for use in forming a vitreous enamel body by fusing the particles together to form the body, at least one enamel frit and at least one non-vitreous additive are formed into an agglomerated granular feedstock and passed through a heating chamber whereby such feedstock becomes at least partially molten and rounded, whereafter the resulting rounded vitreous enamel beads are caused or allowed to cool to a temperature below their melting point.

Abstract: A process for the preparation of monoliths of aerogels of metal oxides, which aerogel is either constituted by one single oxide, or is constituted by a mixture of oxides, is disclosed, which process consists of the following operating steps:(a) the relevant metal alkoxide(s) is/are mixed with water in the presence of a catalyst of acidic character;(b) the so obtained mixture is hydrolysed;(c) a colloidal suspension of the oxide of a metal equal to, or different from, the metal(s) used in the (a) step is added to the hydrolysate;(d) the so obtained colloidal solution is caused to turn into a gel (gelation) having the desired shape and dimensions;(e) the gel is washed;(f) the gel is dried at values of temperature and pressure which are higher than the critical pressure and temperature values of the solvent used for the washing.

Abstract: A substantially dehydroxylated glass is formed by impregnating a dry porous silica gel with a nitrogen-containing organic compound in an organic solvent capable of solubilizing that compound. The impregnated gel is then sintered in a non-oxidizing atmosphere to form a substantially dehydroxylated, fully-densified silica glass. The gel is typically formed by a sol-gel process. The nitrogen-containing organic compound can be guanidine compounds, urea, or mixtures thereof.

Abstract: A silica-based glass rod is inserted into a space portion of a mold. Then, a slurry, which is obtained by dispersing a silica glass powder material in pure water, is poured into a molding space between the glass rod and the inner surface of the mold, whereby a porous glass shaped body is formed around the glass rod. Drying this shaped body results in a silica glass base material which includes the glass rod and the porous glass shaped body surrounding the same.

Abstract: Method of manufacturing tubes in which a mixture of powdered tube material and a liquid binder is introduced into a tubular mold with a geometry corresponding to the geometry of the tube to be formed. The tubular mold is rotated about its longitudinal axis. The powder-binder mixture deposits on the inner wall of the tubular mold. The powder and the liquid are introduced into the tubular mold separately.

Abstract: Fiber-reinforced ceramic matrix composite articles of complex shape are made with improved physical integrity and control over fiber alignment by a process wherein prepreg comprising fibers and powdered matrix is treated to shorten the average length of the fibers, then configured without binder removal into a preform of selected shape and fiber orientation, and finally consolidated with heat and pressure into a dense ceramic matrix composite article. Fiber breakage during the consolidation process is thereby avoided.

Abstract: A quartz glass crucible for use in a process for pulling a single crystal silicon and having an outer layer and an inner layer. The outer layer contains less than 0.3 ppm each of Na, K and Li and more thant 5 ppm of Al. The outer layer further contains bubbles to present an opaque appearance. The inner layer is made by melting powders of high purity non-crystalline synthetic silica and contains less then 200 ppm of OH group. There is also disclosed a method for producing the crucible.

Abstract: In accordance with the present invention, the dopant within one gradient index optical element has two independent concentration distributions. Particularly to use the present invention to obtain a gradient index optical element having an excellent chromatic aberration correction ability, it is only needed to make such dopant distributions as shown in the previously stated Japanese Patent Application No. 280897/1989. However, as to the doping of a dopant into a porous body, there is a limit in the amount which can be doped. This is a disadvantage of the molecular stuffing method, but the reason for this is that the dopant must be supplied into the holes as a solution and it is largely restricted by the solubility of the dopant in the solvent. In addition, since the intra-hole fixing of the dopant depends on the solubility difference by temperature or that by solvent exchange, it is further restricted.

Abstract: A process for easily producing a silica glass plate having an internal refractive index distribution suitable for a planar optical waveguide involves carrying out the following steps.(a) A porous silica gel plate produced by a sol-gel method is kept in a reactor, the pressure of which is reduced to a substantially vacuum state.(b) Germanium tetrachloride gas is introduced into the reactor at a partial pressure appropriate to establish an absorption equilibrium between a desired concentration of germanium tetrachloride in said porous silica gel plate and a partial pressure of germanium tetrachloride introduced.(c) The partial pressure of germanium tetrachloride in step (b) is reduced so as to desorb germanium tetrachloride from the surface of the porous silica gel plate.(d) The porous silica gel plate having a described concentration distribution is brought into contact with water within or outside the reactor so as to fix the distribution.

Abstract: This invention relates to the production of high purity fused silica glass through oxidation and/or flame hydrolysis of a halide-free, organosilicon-R compound in vapor form having the following properties:(a) producing a gas stream of a halide-free silicon-containing compound in vapor form capable of being converted through thermal decomposition with oxidation or flame hydrolysis to SiO.sub.2 ;(b) passing said gas stream into the flame of a combustion burner to form amorphous particles of fused SiO.sub.2 ;(c) depositing said amorphous particles onto a support; and(d) either essentially simultaneously with said deposition or subsequently thereto consolidating said deposit of amorphous particles into a virtually nonporous body; the improvement comprising utilizing a halide-free, organosilicon-R compound in vapor form having the following properties:(1) a Si--R bond dissociation energy that is no higher than the dissociation energy of the Si--O bond;(2) a boiling point no higher than 350.degree. C.

Abstract: In production of a closed package-type semiconductor assembly provided with a built-in semiconductor element and conductive leads for connection to outside devices, a conductive island, the conductive leads and other accessories are united together by one stage moulding of molten glass. Simple process reduces the production cost greatly and no use of dusty ceramic components much raises functional reliability of the product.

Abstract: A mold for the manufacture of non-round glass shapes and method for making such molds. In molds for glass blowing and pressing, especially for producing non-round shapes where molten glass must be in contact with the mold for an extended time, an economical, heat resistant mold adaptable to any shape is produced by mixing defined ratios of water, hydraulic compound and amorphous fused silica to form a pourable composite mixture which is shaped into a mold by placing the mixture on or in a master pattern and curing the mixture at room temperature and then at elevated temperature.

Abstract: A silica glass powder suitable for the production of a silica glass body product of a low silanol content, which is obtained by baking a dried silica gel powder obtained by a sol-gel method, at a temperature of from 1,000.degree. to 1,400.degree. C., wherein during the baking period, the silica gel powder is baked in a gas atmosphere containing from 10 to 100% by volume of steam for at least 5 hours.

Abstract: Disclosed is a method of producing thin films by sintering which comprises:a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, andb. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof.Also disclosed is the article produced by the method claimed.

Abstract: In a method of manufacturing a glass article by means of a sol-gel process, a metal alkoxide is hydrolyzed, dehydrated and condensed to obtain a wet gel. A molding container is used for drying and shrinking the wet gel to obtain a dry gel. A bottom wall of the molding container has an inner surface formed with a recess or recesses. The wet gel is dried and shrunk to form a gap or gaps between the inner surface of the bottom wall and the gel on the way of drying and shrinking. The gap or gaps communicate with a space which occurs between an inner surface of a peripheral wall of the molding container and the gel on the way of drying and shrinking.

Abstract: In a device for producing mold glass bodies, a molding cavity is defined by two mold halves and by two mouth ring halves. One single nozzle head is used for spraying a lubricant on both the inner faces of the mold halves and the connection faces of the mouth ring halves which are to contact the mold halves.

Abstract: A roller conveyor has an aligning device for glazing panes. The conveyor includes a plurality of aligned rollers forming a roller bed and driven for advancing glass panes in a conveying direction. The aligning device includes a rail disposed above the rollers and mounted such that it extends at a small horizontal angle to the conveying direction. The rail is disposed relative to the rollers such that an edge of a pane being conveyed on the rollers engages the rails so as to align the pane. The aligning device also includes a ring disposed in the roller bed downstream of the rail in the conveying direction. The ring has an external diameter larger than that of the rollers and is positioned relative to the rail such that the ring can engage a lower surface of a pane conveyed on the rollers at a position spaced from the center of gravity of the pane, and so rotate the pane.

Abstract: A process for fabricating a composite article is disclosed. A surface of a preconsolidated fiber reinforced glass matrix composite structure is pretreated to promote adhesion to the surface, a mass of fiber-containing uncured resin is molded in contact with the pretreated surface and the resin is cured to consolidate a fiber reinforced resin matrix composite structure and simultaneously bond the resin matrix composite structure to the glass matrix composite structure. A composite article fabricated by the above process is also disclosed.

Abstract: A composite substrate is fabricated by applying to a glass fiber substrate a liquid sol-gel composition and then sintering the sol-gel to convert it to the glass phase. A polymeric coating is then applied.

Abstract: Devices for and a method of manufacturing glass bodies, in which a porous green body is formed from the starting material for the glass body, being an aqueous suspension comprising a highly disperse solids content, which green body is then purified and sintered, and deposited by separating the phases of the suspension through electrophoresis, in such a manner that the solids content of the suspension is deposited on a porous deposition membrane having pores whose diameter is smaller than the average particle diameter of the solid particles present in the suspension, said membrane being arranged between the anode and the cathode, and the space between said membrane and the anode being filled with an electrically conducting liquid, a porous auxiliary membrane being arranged between and at a distance from the deposition membrane and the cathode, said auxiliary membrane having pores with a diameter which is smaller than the average particle diameter of the solid particles present in the suspension, and the space

Abstract: A method is disclosed for preparing an improved bioreactive material of the glass or partially crystallized glass type for bone prostheses or dental implants, which can be welded to bone tissue by chemical bonding. The material consisting essentially of, by weight, 5 to 14% Na.sub.2 O, 0 to 12% P.sub.2 O.sub.5, 49 to 57% SiO.sub.2, and balance, no more than 33% CaO+CaF.sub.2, the material containing 0.5 to 7% CaF.sub.2, and is prepared by a method comprising the steps of preparing a mixture of powders constituting a precursor of the material made of carbonates, phosphates, silica, oxides and fluorides, melting, homogenizing, casting and cooling the mixture to obtain an intermediate, non-crystallized glass, optionally annealing, and then grinding, either pressing the non-crystallized ground glass obtained cold to shape it, then sintering naturally or under a load after degassing, or sintering under a load directly after degassing, then cooling and optionally polishing or machining.

Abstract: A method and composition for protecting a gamma titanium aluminide alloy specimen subject to high temperature oxidation is disclosed. An alumino silicate glass coating is applied on the surface of the gamma titanium aluminide specimen. The coated specimen is heated to a temperature in a range of 2150.degree.-2250.degree. F. for a sufficient time period to form a silicide interfacial layer between the alloy and the glass coating. The glass coating is preferably a composition including SiO.sub.2 in a weight percentage of 60 to 65 Al.sub.2 O.sub.3 in a weight percent of 16 to 20. The glass coating results in minimal oxidation.

Abstract: A composite article, such as a telescope mirror blank, comprising a solid glass body and a supporting network structure, the structure being composed of a network of interlocking struts frit sealed to one another and to the face plate. The article is characterized in that sufficient of the glass body is incorporated in particulate form in the struts to maintain an average expansion mismatch (-50.degree. C. to +50.degree. C.) between the network structure and the glass body of no more than 0.15 ppm/.degree.C.

Abstract: A method of manufacturing a glass or glass-ceramic matrix composite article is disclosed which serves to eliminate the need for an expensive vacuum hot press and to significantly reduce the time required for densification. A preform composed of a mixture of chopped or continuous fibers such as carbon or silicon carbide and glass powder is heated to a temperature sufficiently high to soften the glass powder to a deformable state. Thereupon, the preform is deformed between dies which are at a temperature below that of the preform. A resultant composite article assumes the configuration of the shaped die cavity and is cooled by the natural loss of heat to the dies.

Abstract: A process for producing a ceramic preform, which comprises mixing an alkoxysilane and fine silica powder, molding the mixture, followed by heating for de-alcoholysis.

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 process is provided for forming a glass fiber having one or more metal aments in its core. In the process, a metal rod or particles of a metal or semiconducting material optionally mixed with glass powder is introduced into a hollow glass tube closed at one end, and the tube is evacuated while the closed end is heated and a fiber drawn therefrom. The resultant glass fiber contains one or more discrete filaments of the metal or semiconducting material.

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: A method of manufacturing a vitreous enamel body includes forming particles of vitreous material and melting to fuse the particles together to form the body. The particles of vitreous material are spherulized and are selected as to their granulometric properties according to the degree of compaction required in the finished enamel body. From 20% to 40% of the bulk volume of the mixture is a fine particle size fraction. Such a finished enamel body may be a coating, for example a high-compacity enamel coating on a bathtub, or it may be a self-sustaining body, for example a porous vitreous filter element. Porous coatings and compact self-sustaining bodies may also be made.

Abstract: The present invention is directed to a method for synthesizing highly crystalline pollucite articles at temperatures not exceeding 1650.degree. C. The method comprises two general steps:(a) a glass frit is prepared having a composition varying from approximately the stoichiometry of Cs.sub.2 O.2SiO.sub.2 to approximately the stoichiometry of Cs.sub.2 O.4SiO.sub.2 with, optionally, up to 5% Al.sub.2 O.sub.3 ; and(b) that glass frit is reacted at a temperature between about 1000.degree.-1650.degree. C. with an Al.sub.2 O.sub.3 -containing material in sufficient amounts to yield a final product having a stoichiometry approximating that of pollucite.

Abstract: A method of producing glass bodies having regions with different optical refraction, including a basic body and a coating layer which is sintered onto the basic body, covers the basic body at least partially and is made of glass, which as it is doped, has an index of refraction differing from that of the glass of the basic body. The starting material for producing the cladding on the basis of pulverulent ceramic material is deformed into a self-supporting, unsintered porous green body, is dried and submitted to a cleaning procedure in a heated gas phase. The coating layer to be bonded onto the basic body is melted into glass in a subsequent combined doping/sintering procedure in a gas phase containing the doping agent at a temperature in the range from 1150.degree. to 1500.degree. C. and is sintered onto the basic body.

Abstract: A method of manufacturing a large-diameter gradient-index glass having a predetermined refractive index gradient includes the steps of (a) hydrolyzing a solution consisting of an alkoxide of silicon and an alkoxide of boron to prepare a sol, (b) adding an aqueous solution of lead acetate and an organic acid to the sol to prepare a gel porous body, (c) aging and sequentially treating the gel porous body by using a water-isopropanol solution of lead acetate, an isopropanol-acetone solution, and acentone, thereby performing a pretreatment, (d) dipping the pretreated gel porous body into a lower alcohol solution of at least one of potassium acetate and sodium acetate to form a lead ion concentration distribution which is gradually changed from a surface to an interior of the gel porous body, (e) sequentially treating the gel porous body having the lead ion concentration distribution by sequentially using an isopropanol-acetone solution and acentone, and (f) drying and heating the gel porous body to prepare a glas

Abstract: A process for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry.

Abstract: A granular body, from which an article having a nonuniform refractive index may be formed, has grains of two substances which have different refractive indicies in a geometric distribution in the granular body corresponding to the geometric distribution of the substances required for the nonuniform refractive index of the article and a way of shape-stabilizing the granular body. A method of making the granular body comprises controllably feeding the grains into the geometric distribution in the granular body and shape-stabilizing it. Preferably the granular body is compressed into a porous compact which holds itself together and is treated with a gas to achieve desired optic properties in the article.

Abstract: A method of manufacturing a thermal printer head on a substrate having a heat accumulating layer on a surface thereof, a dot-like heat generating resistor group arranged in a straight line on said surface of said heat accumulating layer, and an electrode group for supplying power to said heat generating resistor group. The heat accumulating layer is formed by the sequential steps of:(1) forming a slip, which contains, as major component, an inorganic powder material for constituting said heat accumulating layer and an organic binder into a green sheet;(2) cutting the green sheet into the shape of heat accumulating layer;(3) laminating the cut green sheet to a predetermined position of the substrate; and(4) firing the green sheet.

Abstract: Apparatus includes a furnace for vitrifying waste material, a storage container for delivering waste material to the furnace and a pipe for passing a heat transfer medium through the storage container to preheat the waste material and remove water therefrom. The pipe may be a pipe through which exhaust gas is passed or a pipe through which a liquid medium is passed after heat transfer from the exhaust gas. The apparatus further includes means for removing dust from the exhaust gas and heating same to break down dioxines and furanes therein.

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 of producing a high purity silica powder which can be fused to form transparent, bubble-free particles. An ammonium fluosilicate solution is purified preliminarily by removing colloidal-sized silica onto which impurities in the solution have been adsorbed. The high purity powder is produced by ammoniation of an unsaturated aqueous solution of ammonium fluosilicate. Silica powder produced is filtered, washed, and dried before fusion. Additional pre-fusion treatments such as washing, hydrothermal leaching, calcination, and a combination thereof, may be utilized to ensure that the concentration of volatile material is low.

Abstract: Machinable ceramics with 30-60 vol. % of fine crystals of fluorophlogopite, a synthetic mica, evenly dispersed in a vitreous matrix is produced using as principal raw materials kaolin and activated clay, which are natural minerals, other than metal oxides themselves. According to the production process, a mixture of fine particulate raw materials is calcined under first heat treatment conditions in which a maximum temperature is in the range of 1,000.degree.-1,100.degree. C. The raw materials include kaolin and activated clay as principal raw materials, Mg-containing, K-containing and F-containing compounds as auxiliary raw materials and B.sub.2 O.sub.3 as a sintering aid. The resulting calcined mass is ground into fine particles, followed by the formation of a green body of a desired shape. The green body is then sintered into a fired body under second heat treatment conditions in which a maximum temperature is in the range of 1,100.degree.-1,250.degree. C.

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 method for molding high temperature composites that transmits more uniform pressures to the surface of the composites. A compliant glass, glass-ceramic, or ceramic layer is caused to apply pressure to a composite precursor and heat is applied to the composite precursor to form a composite.

Abstract: A beam carries two abutments and is moveable on the conveying direction of the conveyor. Starting from rest, the beam is accelerated to a speed less than that of the glass sheet moving on the conveyor, so that the glass sheet contacts the abutments while both are moving along the conveyor. Once the glass sheet is correctly oriented, the beam is accelerated and raised to permit the passage of the glass sheet. The beam is then retracted to the initial position for the next cycle of operation.

Abstract: A method is disclosed for recycling reinforced plastic composite materials. The reinforced plastic composite material is heated to separate said plastic matrix material from said reinforcement material. At least the separated reinforcement material is recycled. The products produced by these methods and processes are also disclosed.

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.