Abstract: A solid solution and a process for producing a solid solution, the solid solution including at least the compounds: silicon carbide and aluminum oxycarbide, and also aluminum nitride. The new material including all three compounds is referred to by the acronym, SiCAlON, which is a coined term consisting of the chemical abbreviations for the elements present in the solid solution. The solid solution is obtained by heating an intimate mixture of reactants above about 1550.degree. C. The silicon carbide in the solid solution has the alpha or hexagonal structure and the aluminum nitride has the wurtzite or hexagonal structure. The solid solution is characterized by the substantial absence of iron or other impurities that tend to encourage the formation of silicon carbide as a separate phase having a beta or cubic structure.

Abstract: A method is disclosed for preparing a dense, B"-alumina-containing ceramic body exhibiting an electrical resistivity for sodium ion conduction at 300.degree. C. between about 3 and about 20 ohm-cm, by sintering a green ceramic body formed from a composition comprising at least about 90 weight percent of aluminum oxide, about 8.7 to 9.4 weight percent of sodium oxide, about 0.7-0.9 weight percent of lithium oxide, and from 0.0 to about 4.0 weight percent of magnesium oxide at a temperature between about 1400.degree. C. and about 1600.degree. C., for between about three (3) minutes and about 180 minutes to obtain a body containing both B and B"-alumina crystalline forms. The sintered body exhibits a density greater than 90% of theoretical for polycrystalline B"-alumina and a uniform grain size between about 20 and 100 micrometers. All of these compositions were prepared by using either a binary liquid forming mixture between sodium aluminate (NaAlO.sub.2) and lithium aluminate (LiAlO.sub.

Abstract: A process for removing silicon from a silicate-bearing material. The silicate-bearing material is analyzed for its silicon content and mixed with a controlled quantity of carbon as indicated by the analysis. The carbon is limited to an amount less than the stoichiometric amount necessary to react with the silicon to form silicon carbide. The silicate-bearing material/carbon mixture is formed into a first phase and interposed with a second phase containing additional carbon to form a reaction mixture. The reaction mixture is subjected to a carbothermal reduction reaction to reduce silica in the silicate-bearing material to silicon monoxide. At the temperatures involved in the reaction, the silicon monoxide is in the gaseous phase and readily diffuses from the first phase into the second phase where the diffused silicon monoxide reacts with the additional carbon in the second phase to form silicon carbide.

Abstract: Methods of preparing a dense and strong polycrystalline .beta."-alumina-containing ceramic body exhibiting an electrical resistivity for sodium ion conduction at 300.degree. C of 9 ohm-cm or lower obtained directly after sintering and having a controlled fine microstructure exhibiting a uniform grain size under 50 micrometers. The invention more particularly relates to methods of uniformly distributing selected metal ions having a valence not greater than 2, e.g. lithium or magnesium, uniformly throughout the beta-type alumina composition prior to sintering to form .beta."-alumina. This uniform distribution allows more complete conversion of .beta.-alumina to .beta."-alumina during sintering. As a result, the polycrystalline .beta."-alumina containing ceramic bodies obtained by methods of this invention exhibit high density, low porosity, high strength, fine grain size (i.e.

Abstract: A method for preparing a dense and strong polycrystalline .beta."-alumina-containing ceramic body exhibiting an elecrical resistivity at 300.degree. C of 5 ohm-cm or lower, and a controlled and uniform grain size under 50 micrometers, comprising:A. preparing fully converted .beta."-alumina seeds;B. mechanically mixing in the above-mentioned .beta."-alumina seeds with a matrix powder of a composition consistent with the formation of .beta."-alumina upon sintering; andC. sintering at about 1600.degree. C for less than 10 minutes in an open-air atmosphere or under noble metal encapsulation, a green ceramic body formed from the powder mixture of which one ingredient is the .beta."-alumina seeds and the other ingredient is the matrix powder of a composition consistent with the formation of .beta."-alumina.The polycrystalline .beta."-alumina-containing ceramic bodies obtained by the method of this invention exhibit high density, low porosity, high strength, fine grain size, and low electrical resistivity.

Abstract: A method of producing a sinterable refractory material having a low coefficient of thermal expansion and comprising essentially a dispersion of aluminum oxide throughout a silicon nitride matrix, herein called SIALON. The process includes obtaining aluminum and silicon from generally readily available raw material sources.