Norton Company

Malcolm E Washburn

Joseph N Panzarino

Stephen D Hartline

Cecil M Jones

Louis J Trostel, Jr

Anil K Agarwal

Charles W Taylor

The present invention is an electrical device made up of a mixture of silicon carbide and molybdenum disilicide, and may include silicon nitride or aluminum nitride or boron nitride. An electrical device is also disclosed which is particularly suited for use as an igniter in liquid and gas fuel burning systems. The device is made up of a sintered, preferably hot-pressed, mixture of fine powders of aluminum nitride or silicon nitride, silicon carbide and molybdenum disilicide where, when all three are present, they are present in substantial quantities.

Refractory electrical device

An improved silicon nitride bonded silicon carbide refractory is disclosed. The improvement results from coating the silicon carbide grains with, or introducing into the bond during the mix preparation step, zirconium orthosulfate. The resulting product has higher moduli of rupture and elasticity as compared to prior art compositions where zirconia is introduced into the bond.

High strength nitride bonded silicon carbide refractories

An oxygen sensing package includes a solid electrolyte sensor and a silicon carbide heating element arranged so as to surround the solid electrolyte and radiate heat to it from convex surfaces. n

Self heated sensor package

The gasification of coal can be accomplished more efficiently if it is operated at a temperature high enough so that the mineral constituents of the coal will form a molten slag which can be continuously removed from the gasifier during operation. Proper control of such a process requires careful temperature control, but the molten coal slag has been found to be corrosive to most thermocouple materials and to conventional refractory ceramics which are used as thermocouple protection tubes in other environments. It has now been found that magnesium chromite serves satisfactorily as a corrosion resistant refractory material in molten coal slags, and that thermocouple protection tubes of this material can be made by isostatic pressing of granular magnesium chromite and subsequent firing.

Refractory bodies for corrosive environments

A novel raw batch and improved fired refractory cement is described. A bulk refractory grain mass is initially bonded with a fired bond, which upon being fired includes Si.sub.3 N.sub.4 and/or Si.sub.2 ON.sub.2 reaction component that better protects the ultimate high temperature sintered cement product from erosion when the cement is used as a liner for furnace walls, troughs, and runners that contain a flow of molten iron or slag, as well as induction furnaces which process corrosive slag.

Refractory cement

A reaction bonded silicon oxynitride product having a density of 85 to 95% of theoretical density, a degree of density heretofore not attainable by sintering or reaction bonding. Such high densities are attained by nitriding, in an oxygen free atmosphere ultra fine silicon and ultra fine silica in the presence of certain reaction aids. The particle size of the silicon powder must be at least as fine as about 3 microns and the silica as fine as about 0.3 microns.

High density silicon oxynitride

A new form of reaction bonded silicon nitride is described along with the process of making this new product. The product is characterized by isotropic structure, extremely fine pore and grain size, high strength and a high ratio of alpha silicon nitride to beta silicon nitride. The product has a density of at least 2.45 grams/cc and is essentially free of pores greater than 15 microns.

Reaction bonded silicon nitride

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.

Porous silicon oxynitride refractory shapes

A lightweight insulating refractory shape is made of Si.sub.2 ON.sub.2 having a density of less than 50% of theoretical, a relatively high compressive strength, a low thermal conductivity and high resistance to attack by chlorine, fused chlorides and molten aluminum.

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Princeton, MA, United States of America

Malcolm E Washburn