Abstract: A shrink resistant flexible ceramic fiber and its process of manufacture which comprises melting from about 40 to 65 weight percent of alumina with from about 35 to about 60 weight percent of silica, forming fibers from the melt, rapidly solidifying the fibers, heating the fibers to a sufficient temperature for a sufficient time to form microcrystals and cooling the fibers to below the crystallization temperature before macrocrystals can form.

Abstract: A process for strengthening carbide fibers by removing internal stresses caused by their formation. This process is accomplished by drawing the carbide fiber under tension through a furnace. The temperature of the furnace may range from about 2050.degree. to 2300.degree. C. while the fiber tensile stress may vary from about 200 to 3500 p.s.i. when using boron carbide fibers with diameters ranging from about 8 to 14 microns.

Abstract: A method of pressureless sintering silicon carbide mixtures to obtain a sintered, dense product when the silicon carbide starting materials do not include a densification aid, such as boron, beryllium or aluminum, is described. The starting materials are mixtures containing predominantly particulate silicon carbide and include usually less than about 10 and, preferably, less than about 6 percent by weight of carbon in the form of elemental carbon or in the form of a carbon source material. The mixtures may also contain minor amounts of other additives, such as lubricants, surfactants or agglutinants, to aid in forming a compact, or green body, from the mixtures, or minor amounts of other ceramic materials depending upon the nature of the desired final product. The mixtures are formed into compacts, or green bodies, by known techniques.

Abstract: An apparatus for fuel ignition comprising an electrical source for providing electrical current; an electrically operated fuel ignition means; a valve means which allows passage of fuel to the ignition means when the valve means is opened; a first valve control means which will open the valve upon application of an electrical current and a second valve control means which will retain the valve means in an open position but will not initially open the valve upon application of an electrical current; an activating switch electrically connected between the electrical source and the rest of the apparatus so that the apparatus will not operate unless the activating switch is closed; a time delay switch connected between the activating switch and the rest of the apparatus and connected to an ignition sensing switch means so that the time delay switch stops the flow of electrical current to the rest of the apparatus if the ignition sensing switch means does not sense ignition within the time delay; and an ignition s

Abstract: Ceramic compositions that may be injection molded and subsequently sintered are described. A particulate ceramic material, such as silicon carbide, is coated with a mixture of thermoplastic resin and oils or waxes, and utilized as a feed material in an injection molding process. The molded product may subsequently be sintered at 2000.degree. C. to 2200.degree. C. to produce a hard, dense article.

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: A neutron absorbing article, preferably in long, thin, flat form, suitable for but not necessarily limited to use in storage racks for spent nuclear fuel at locations between volumes of such stored fuel, to absorb neutrons from said spent fuel and prevent uncontrolled nuclear reaction of the spent fuel material, is composed of finely divided boron carbide particles and a solid, irreversibly cured phenolic polymer, forming a continuous matrix about the boron carbide particles, in such proportions that at least 6% of B.sup.10 from the boron carbide content is present therein.

Abstract: A coated abrasive belt backing material woven from 100% high tenacity polyester staple yarns in a sateen weave is heat set and destretched to a dimensional stability warpwise of less than 6.5% elongation at 170 pounds per linear inch of width tensile, while maintaining its desired width during such heat setting and destretching, cloth finished, coated with maker, abrasive and size, cured and product finished to form endless belts having superior properties of strength, toughness, body retention, pliability and base adhesion.

Abstract: A composite, neutron absorbing, coated article, suitable for installation in storage racks for spent nuclear fuel and for other neutron absorbing applications, includes a backing member, preferably of flexible material such as woven fiberglass cloth, a synthetic organic polymeric coating or a plurality of such coatings on the backing member, preferably of cured phenolic resin, such as phenol formaldehyde or trimethylolphenol formaldehyde and boron carbide particles held to the backing member by the cured coating or a plurality of such coatings. Also within the invention is a method for the manufacture of the neutron absorbing coated article and the use of such an article.

Abstract: Neutron absorbing articles, such as those in plate form suitable for use in a storage rack for spent nuclear fuel and having such properties as to make them useful in such application for long periods of time, are made by an improved one-step curing method in which a mixture of boron carbide particles, powdered phenolic resin and a minor proportion of a liquid medium which boils at a temperature below 200.degree. C., preferably water, is compacted to desired article form and is cured at an elevated temperature, without simultaneous imposition of pressure in compacting or pressing means, so as to cause bonding of the irreversibly cured phenolic polymer resulting to the boron carbide particles and production of the neutron absorber in desired form.

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: Ceramic compositions that may be injection molded and subsequently sintered are described. The compositions include minor amounts of organo-titanates which materially reduce the viscosity of the compositions. The reduction in viscosity is particularly effective in compositions containing high loadings of silicon carbide as the ceramic material. The organo-titanates found useful are represented by the formula:(R.sub.1 --O).sub.m --Ti--(O--X.sub.z --R.sub.2).sub.nwherein:(a) m is an integer from 1 to 8 andn is an integer from 0 to 4,(b) m+n=4,(c) z is an integer from 0 to 1,(d) R.sub.1 is aliphatic containing 1 and 4 carbon atoms,(e) X is independently selected from the group of phosphite, phosphate, and pyrophosphate.(f) R.sub.2 is aliphatic containing from 8 to 25 carbon atoms.

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: 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.