Abstract: A porous refractory body is formed by bonding Si.sub.2 ON.sub.2 grain or other suitable refractory grain with fine crystals of Si.sub.2 ON.sub.2 formed in situ by firing a shaped body under nitridation conditions. The body has an open pore structure, is resistant to the constituents of an aluminum chloride electrolysis cell and has good structural strength.

Abstract: Refractory materials with high sintering temperatures are made suitable for use as low temperature setting dry vibration cements, ramming cements, gunning cements, and the like by incorporation therein of up to 4% boric acid and a low temperature softening glass or frit. The lower temperature softening frit is finely ground and uniformly mixed with a refractory grain or aggregate. When the mixture is subjected to a temperature as low as 350.degree. C, the frit softens and bonds the refractory grain into a monolithic structure which retains its integrity up to and through the elevated temperatures at which the refractory grains sinter and other high-temperature ceramic bonds form.

Abstract: Silicon nitride based refractory articles with flexural strengths at room temperature of up to 150,000 p.s.i. and at 1375.degree. C of up to about 117,000 p.s.i. result when mixtures of 80 to 98.5% by weight of silicon nitride, 1 to 15% by weight of yttrium oxide, and 0.5 to 10% by weight of thorium oxide are pressure sintered according to conventional methods.

Abstract: An adhesive composition which, in the preferred aspects of the invention, is a partially cured reaction product of the composition in the form of a dried, preformed film that is heat-activatable, is provided comprising in admixture a poly-functional active hydrogen containing component consisting of, in combination, a hydroxyl terminated polyurethane polyester having a hydroxyl number no greater than about 15 and a member containing at least difunctional active hydrogen having an active hydrogen equivalent weight of at least about 27 and less than about 500, a component having available free isocyanate groups, and a fourth component such as a chlorinated aliphatic hydrocarbon, a chlorinated aromatic hydrocarbon, or an alkylated polystyrene.

Abstract: Silicon carbide articles are formed by wet milling a mixture of silicon carbide having an average particle size less than 10 microns, and colloidal graphite; eliminating powder agglomerates larger than 325 mesh (U.S. Standard Sieve Series); drying the milled powder and pressing it to the desired shape; and finally, firing the preform at approximately 2000.degree. C. in the presence of silicon, converting the graphite to silicon carbide.

Abstract: A ceramic resistance gas igniter comprised of 10 to 60% by weight of silicon carbide and 40 to 90% by weight of silicon nitride, slicon oxynitride, or silicon aluminum oxynitride, and having a density preferably greater than 95% of the theoretical density of the composite. As a result of the combination of high density and composition, the igniters have moduli of rupture in excess of 80,000 p.s.i., a resistivity range of from 0.1 to 10.sup.4 ohm centimeters, and superior resistance to corrosive gases.

Abstract: Process tube, paddle, and boat for a semi-conductor diffusion furnace composed of a matrix of high purity sintered silicon carbide which is made impervious to gases by impregnation thereof with silicon metal which is 99.9% pure. The process tube, paddle and boat provide the ultra pure environment needed for semi-conductor production and are highly resistant to the degradative effect of a great number of high temperature heating cycles.