Abstract: Infusible cured phenolic resin fibers of the present invention have a birefringence of at least 2.times.10.sup.-3 with the x-ray diffraction pattern of the fibers showing an amorphous halo. The tenacity of infusible cured phenolic resin fibers is significantly increased by subjecting the fibers to sufficient longitudinal tension as to cause at least about 30% elongation of the fibers. The Young's modulus of elasticity of the fibers is also significantly increased thereby. Preferably the resulting stretched infusible cured phenolic resin fibers have a tenacity of at least about 4 g./den.

Abstract: A composition comprising negatively doped hot pressed particulate silicon carbide, the process for making the composition, an electrical hot surface fuel ignitor manufactured from the composition, a silicon brazed electrical connection for the ignitor and an ignitor circuit containing a dropping resistance.

Abstract: The invention comprises the process for making an inorganic refractory insulation article by forming a fiber mat from a fiber slurry, impregnating the mat with a conditioned colloidal silica composition comprising colloidal silica, acid, aluminum chlorhydrate and water and drying the mat to form the article. The invention further comprises an inorganic refractory insulation article comprising randomly oriented refractory fibers retained by dried colloidal silica uniformly distributed throughout the article and from about 0.001 to about 1.5 weight percent of aluminum chlorhydrate which article is manufactured in accordance with the process.

Abstract: Apparatus for mounting a plurality of centrifugal throwing wheels within a blast drum contained within a blast cabinet such that the throwing wheels are carried by a set of tracks which permit the throwing wheels to be rolled into and out of the blast cabinet. A feed screw is located within the blast drum for transporting abrasive particles to the throwing wheels and cooling ducts are located within the blast drum for carrying a flow of air to the throwing wheels. The feed screw and cooling ducts are fixedly located within the blast drum and do not move when the throwing wheels are retracted therefrom.

Abstract: A one-step curing method for the manufacture of neutron absorbing articles, such as those of long thin plate form for use in storage racks for spent nuclear fuel, includes curing a mixture of boron carbide particles, phenolic resin in liquid state and phenolic resin in particulate solid form at an elevated temperature to produce a neutron absorbing article containing at least 6% of B.sup.10 content from the boron carbide thereof, 60% to 80% of boron carbide particles and 40% to 60% of irreversibly cured phenolic polymer, with the proportion of weight of phenolic resin in liquid state to that of phenolic resin in solid state being within the range of about 1:0.5 to 1:4, the temperature of the cure being in the range of about 130 to 200.degree. C. and the cure being effected over a period of about two to twenty hours.

Abstract: A method of removing nitrogen oxides (NO.sub.x) from exhaust gas mixtures is described. The removal of NO.sub.x from exhaust gas mixtures is accomplished by exposing the exhaust gas mixture, in a manner that does not substantially impede the gas flow, to a ceramic material containing from about 75% to about 95% by weight silicon carbide and from about 0.3% to about 10.0% silica. A reduction of at least 85% of NO.sub.x from the mixture is to be expected and reductions up to 95 to 100% are attainable. Ceramic mixtures containing silicon nitride in amounts between about 10% and about 30% are found to reduce the amount of NO.sub.x in exhaust gases at temperatures as low as 200.degree. C.

Abstract: Pressureless sintered silicon carbide ceramic bodies, having an equiaxed microstructure and an alpha crystalline habit can be produced by firing shaped bodies, containing finely divided silicon carbide, boron source such as boron carbide, carbon source such as phenolic resin and a temporary binder, at a sintering temperature of from about 1900.degree. C. to about 2250.degree. C., depending on the sintering atmosphere, under conditions such that a coating of carbon source is maintained on the finely divided silicon carbide, and sufficient boron is maintained within the shaped body during firing. Boron can be maintained within the shaped body by various techniques, such as the use of a "seasoned boat" or graphite container for the body being sintered, which has been saturated with boron by exposure to boron at or about the temperature of sintering.

Abstract: The present invention relates to fiber reinforced carbon and graphite articles that are characterized by a matrix of fibrous carbon material bonded together by a deposited pyrolytic material and having the residue of a carbonized filler material dispersed within the article in contact with the pyrolytic material.Fiber reinforced carbon and graphite articles are produced by(1) Forming reinforcing fibers into a shape without any binder material,(2) Infiltrating the fibers with a pyrolytic material in a manner to deposit pyrolytic material on the fibers and bond together the fibers, to form a bonded body,(3) Subsequently impregnating the bonded body with a carbonizable filler material, and,(4) Curing and carbonizing the filler material.The articles are substantially free of internal cracks and voids and are of high strength even at relatively low densities. As such, the articles are particularly useful in the aerospace industry where strong, lightweight materials are required.

Abstract: A refractory moldable composition which, upon drying, sets up to refractory shapes which are strongly adherent to the molding surfaces and are essentially crack-free, contains about 45 to about 65% of a liquid vehicle, such as water; about 21 to about 26% ceramic fiber; about 7 to about 30% finely divided silica; and sufficient adhesion enhancing agent to impart from about 18 to about 50 grams per square centimeter adherence to steel. The molded composition adheres excellently to molding surfaces and dries to give an essentially crack-free refractory shape, useful as thermal insulation at temperatures up to 1300.degree. C. The composition may optionally include hollow plastic or ceramic spheres.

Abstract: A sinterable silicon carbide mixture is described which is prepared by mixing finely-divided silicon carbide containing between about 0.5 and about 5.0 percent by weight of excess carbon with a finely-divided beryllium-containing additive wherein the amount of beryllium in the mixture is equal to between about 0.03 and about 1.5 percent by weight of the powder. A dense silicon carbide ceramic product is prepared from the powder mixture by pressureless sintering wherein the article is initially shaped and subsequently sintered in a beryllium-containing atmosphere at a temperature from about 1950.degree. to about 2300.degree. C.

Abstract: Gas is injected into molten metal, such as aluminum, to purify the molten metal either of dissolved gases (degassing), or of dissolved solids such as magnesium ( "demagging"). The apparatus for accomplishing this injection contains two metallic bath chambers, the molten metal being transferred from one chamber to the other through a conduit. A gas injection conduit is connected to the metal transfer conduit at a location submerged within the first metallic bath chamber from which metal is transferred to the second chamber, and the gas to be injected is introduced through this gas injection conduit into a location submerged within the first metallic bath chamber.

Abstract: Corrosive chemicals are contained in metallic vessels, the inside portion of which is coated with a homogeneous, porous polymer containing inorganic filler. The particle size, shape and distribution provides a controlled porosity which allows entrapped permeants from the corrosive chemical to escape, yet does not significantly affect the utility of the protective coating as a chemical corrosion barrier protecting the metallic vessel.

Abstract: Apparatus and method are provided for producing a blast pattern with a centrifugal throwing wheel for alternatively providing a blast pattern having a conventional length and for providing a blast pattern having a shorter length than heretofore possible with a standard throwing wheel.

Abstract: A process for the manufacture of an aluminum oxide or zirconium oxide fiber comprising fiberizing a liquid containing lactic acid and an oxidizable compound selected from basic aluminum chloride, zirconium acetate and zirconium oxychloride and the resulting fibers. The liquid optionally also contains colloidal silica.

Abstract: A fused abrasive grain, useful for inclusion in coated abrasives and bonded abrasives, consists essentially of alumina; titanium oxide containing from about 0.42 to about 0.84% titaniun, by weight of the abrasive grain, present as a reduced titanium oxide having an average oxidation state lower than in Ti.sub.2 O.sub.3 ; from about 0.05 to about 0.3% by weight carbon; from about 0.02 to about 0.1% by weight Na.sub.2 O; and from 0 to about 0.1% by weight total of calcium and silicon oxides. The grain before roasting has a gain on ignition of from about 0.4 to about 0.7% by weight, and is produced in an electric furnace by fusing high-purity titania, alumina containing Na.sub.2 O as the only significant oxide impurity, and carbon, followed by crushing and roasting the fused grain.

Abstract: Granular activated carbon is manufactured from sub-bituminous coal by crushing and screening the as received coal containing about 10 to about 25% moisture by weight to produce 8/30 mesh granules, treating the granules with a dilute aqueous solution of inorganic acid at a concentration from about 1 to about 25% by weight to reduce the volatile content and thereby increase the fixed carbon content, the particular concentration being selected to provide the desired activity and porosity of the activated carbon, comprising: mixing the granules with the acid, washing off the acid, and drying the granules at least partially to a moisture content below about 25% by weight. The granules are mixed with from 0 to about 15% by weight of coal tar pitch.

Abstract: There is disclosed a device for securing refractory and/or insulating material against a furnace wall. The device comprises a metal pin or stud which is attached to the wall at one end and is provided with a plurality of notched portions adjacent the other end. The stud cooperates with a hollow, preferably ceramic anchor, which is provided with a rectangular slot that fits over the notched portion of the stud and may be secured thereon by rotating an anchor through 90 degrees to effect a locking arrangement. The anchors may be interfitted in order to provide a support for electrical heating elements. The significant feature is that the size of the anchor is such as to allow another anchor to interlock and make a collar which can support electrical heating elements. As the anchor is preferably a ceramic support it is electrically insulating, and prevents the electrical heating elements from contacting the studs.

Abstract: A neutron absorbing article, preferably in flat plate form and suitable for use in a storage rack for spent nuclear fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total content of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications.

Abstract: Granular activated carbon is manufactured from briquettes of about 1".times.2", formed from brown coal, from which iron material has been extracted and which has a moisture content of about 15% by weight, by crushing and screening the pretreated coal briquettes to produce 8/30 mesh granules, treating the granules with a dilute aqueous solution of inorganic acid (H.sub.2 SO.sub.4, H.sub.3 PO.sub.4 or HCl) at a concentration of about 1 to about 10% by weight to reduce the volatile content and thereby increase the fixed carbon content comprising: mixing the granules with the acid, washing off the acid, and drying the granules at least partially to a moisture content below about 25% by weight. In one case the washed granules are dried partially to a moisture content of about 10 to about 25% by weight without the addition of a carbonaceous binder such as coal tar pitch. In the other case the granules are dried thoroughly and mixed with about 5 to about 15% by weight of coal tar pitch.

Abstract: Disclosure is made of a high-density, high-strength silicon carbide ceramic material that is produced using a silicon carbide powder containing boron or boron-containing compound as a densification additive by the utilization of boron in the sintering atmosphere.