Abstract: A superrefractory dry ramming material based on zirconium oxide for the lining of induction-type crucible furnaces comprising a zirconium oxide low in SiO.sub.2 and conventionally stabilized with CaO, MgO, Y.sub.2 O.sub.3, rare earths or their mixed oxides which has a particle size ranging from 0 to 8 mm, and from 5 to 40 weight percent finely divided monoclinic, fused zirconium oxide containing less than 0.5 weight percent SiO.sub.2.

Abstract: A refractory composition for use in the manufacture of pipes for casting steel, the composition consisting essentially of: (a) from 96 to 98% by weight of zirconia which is partially stabilized by CaO, MgO or Y.sub.2 O.sub.3, at least 90% of which has a particle size of between 0.1 and 10 .mu.m, and (b) from 2 to 4% by weight of an aluminous hydraulic binder, this composition having the following overall chemical analysis: 1.4 to 3.2% by weight of Al.sub.2 O.sub.3, 3.7 to 4.6% by weight of CaO, or 0.36 to 1.15% by weight of CaO plus 2.7 to 3.5% by weight of MgO, or 0.36 to 1.15% by weight of CaO plus 5.36 to 8.80% of Y.sub.2 O.sub.3, less than 1% by weight of SiO.sub.2 +Na.sub.2 O+Fe.sub.2 O.sub.3 +TiO.sub.2 taken together, and ZrO.sub.2 to make up to 100%.

Abstract: A refractory mix comprising an acid stabilized aqueous zirconia sol and an active refractory material in an amount effective to gel said sol and articles prepared therefrom.

Abstract: A low thermal expansion cordierite ceramic is produced by combining cordierite with a zirconium compound and a phosphorus compound and sintering the resultant mixture thereby giving rise to zircon therein.

Abstract: Spray-coating materials having a high heat-resistance and thermal conductivity for the surface protection of materials. The spray-coating material consists of 8-35 wt. % magnesium oxide MgO or calcium oxide CaO, 2-10 wt. % of beryllium oxide BeO and 55-90 wt. % of aluminum oxide Al.sub.2 O.sub.3, zirconium dioxide ZrO.sub.2, silicon dioxide SiO.sub.2, chromic oxide Cr.sub.2 O.sub.3 and titanium dioxide TiO.sub.2. The spray-coating material of the invention can be employed to advantage, for example, in the chemical industry and in metallurgy.

Abstract: Zirconia ZrO.sub.2, ceria CeO.sub.2 or thoria ThO.sub.2 may be rendered ionically conductive; a typical composition is ZrO.sub.2 +12 mol % CaO.This is sintered in the solid state as a 40 nm powder using as a sintering additive 0.1 mol % MgO at 1450 C. for 4 hours; a density 98% of the theoretical is achieved.For other fluorite oxide compositions, MgO is also useful as a sintering additive but in different proportions.

Abstract: A novel process for fabricating novel high zirconia content refractory articles directly from novel sinterable compositions including as the major ingredient thereof baddeleyite ore concentrates thereby reducing costs. Appropriate additives, particularly zircon, further provide enhanced resistance to thermal shock damage. Plasticizers, binders and other processing aids are identified for press forming exemplary compositions into continuous casting nozzles, shrouds and other ceramic products typically used in the processing of molten steel, specialty metals and glass.

Abstract: Sheathed electrical heating elements containing MgO heat conductive, electrical insulating material having a high degree of calcination together with additives in the form of a clay and fumed silica to increase the electrical resistivity, density and flow properties.

Abstract: A material for magnetic head sliders comprises a mixed powder consisting of 40 to 80% by weight of Al.sub.2 O.sub.3 and 20 to 60% by weight of TiO.sub.2, and further contains, per 100 parts by weight of the Al.sub.2 O.sub.3 and TiO.sub.2 mixture, 0.5 to 5 parts by weight of at least one of CaO, MgO and Y.sub.2 O.sub.3, and 0.5 to 10 parts by weight of ZrO.sub.2.

Abstract: Materials, methods and articles for the electrochemical determination of sulfur and carbon in fluids are provided. In accordance with a preferred embodiment, an electrolyte is furnished comprising a solid solution of an oxide of either zirconium, thorium or hafnium together with an oxide of an element of groups IIA or IIIB of the periodic table of the elements together with a sulfide or carbide of an element of groups IIA or IIIB of the periodic table. Processes employing such electrolytes together with articles incorporating them are also contemplated.

Abstract: A ceramic formed body having high temperature change resistance and stren and being composed of a ceramic matrix with dispersed particles of ZrO.sub.2, HfO.sub.2, or mixture thereof, is formed of a powdered ceramic material which is a precursor to the matrix material of the ceramic matrix, mixed with a compound which can form ZrO.sub.2, HfO.sub.2 or mixture thereof upon reaction with the ceramic material, and thereafter densely sintered below the reaction temperature. The sintered body is then heat treated above the reaction temperature to convert the precursor ceramic material into the matrix material and form the ceramic body with in situ formation of the dispersed particles.

Abstract: There is provided a refractory mix comprising an acid stabilized aqueous zirconia sol and an active refractory material in an amount effective to gel said sol.

Abstract: Sheathed electrical heating elements containing MgO heat conductive, electrical insulating material having an additive of fine particles of spherically shaped fused ZrO.sub.2 to increase the electrical resistivity and maintain favorable tap density and flow properties. The spherically shaped ZrO.sub.2 particles are formed by gravitationally separating the ZrO.sub.2 particles from ground fused zircon (ZrO.sub.2.SiO.sub.2).

Abstract: A composition is disclosed of about 0.45 to about 5.5 percent of an organic water-soluble binder which has a thermal decomposition temperature of about 100 to about 500.degree. C. and a viscosity of less than about 10,000 poises at 20.degree. C., about 1.5 to about 4.0 percent of a starch which has a thermal decomposition temperature of about 250 to about 535.degree. C. where the thermal decomposition temperature of the binder and the starch are at least about 50.degree. C. apart, about 1.5 to about 3.5 percent cellulose, about 0.5 to about 2.0 percent of a dispersant, and about 7 to about 11 percent water, and about 75 to about 89 percent of a high temperature refractory material such as stabilized zirconia. The composition is de-aired, formed into a shape, and fired to produce a ceramic structure.

Abstract: The present invention relates to a metal-oxide ceramic composition useful in induction heating applications for treating uranium and uranium alloys. The ceramic composition is electrically conductive at room temperature and is nonreactive with molten uranium. The composition is prepared from a particulate admixture of 20 to 50 vol. % niobium and zirconium oxide which may be stabilized with an addition of a further oxide such as magnesium oxide, calcium oxide, or yttria. The composition is prepared by blending the powders, pressing or casting the blend into the desired product configuration, and then sintering the casting or compact in an inert atmosphere. In the casting operation, calcium aluminate is preferably added to the admixture in place of a like quantity of zirconia for providing a cement to help maintain the integrity of the sintered product.

Abstract: A method is provided for producing a sintered zirconia article excellent in thermal shock resistance and high in sintered density. The method comprises mixing zirconia powder as the starting material and a stabilizing agent with a definite amount of partially stabilized zirconia powder, shaping and sintering the mixture, and heat treating it under specific temperature conditions.

Abstract: A high zirconia fused refractory product consists essentially of the following constituents analytically, on a weight basis:85% to 97% of ZrO.sub.2 ;0.1% to 3% of P.sub.2 O.sub.5 ;2% to 10% of SiO.sub.2 ;up to 3% of Al.sub.2 O.sub.3without a substantial amount of a rare earth oxide.

Abstract: A sintered ceramics for cutting tools having a relative apparent density of not less than 98% is obtained by sintering a mixture substantially consisting of 80-95% by volume alumina and the balance of titanium nitride and Zr-containing component(s) such as Zr, ZrC and/or ZrN wherein the volumetric ratio of TiN /Zr-containing component(s) ranges 95/5-50/50 in vacuum and/or vacuum inert atmosphere. Although the present invention does not need any application of hot pressing or HIP process, the resultant ceramics has an improved abrasion resistance comparable to those obtained by the latter processes.

Abstract: The invention provides a particulate sealing material for use in preparing hermetic seals between ceramic and cermet members, which material comprises at least 70 wt. % refractory oxide and minor quantities of non-vitreous additive comprising SiO.sub.2, MgO and B.sub.2 O.sub.3. This particulate sealing material is conveniently pressed into the form of a coherent element shaped to suit the particular sealing operation concerned, e.g. the sealing of an open end of a ceramic arc tube to a cermet closure therefor. The invention also provides a method of sealing a ceramic component to a cermet member by interposing said sealing material between the opposed faces of the component and member and applying heat and pressure to sinter the sealing material and achieve a seal between the component and member.

Abstract: A silicon nitride based ceramic tool is disclosed which is prepared from the starting powder compositions surrounded by and including the lines defined by the points A, B, and C and preferably D, E, and F in the FIGURE.

Abstract: Addition of from about 1.0 to about 15% by weight of a vanadium oxide or boric oxide promoter to a zirconia (ZrO.sub.2) powder promotes rapid densification at temperatures below about 1300.degree. C. For example, a density of greater than 92% of estimated theoretical density can be achieved by addition of 4% by weight of ZrV.sub.2 O.sub.7 to monoclinic ZrO.sub.2 and sintering at 1100.degree. C. for about 24 hours. Sintering at temperatures below about 1150.degree. C. avoids the destructive monoclinic/tetragonal phase transformation and provides for better control of microstructure and composition. A density of greater than 98% of estimated theoretical density can be achieved by addition of from about 2 to about 5% by weight of a boric oxide promoter to stabilized cubic ZrO.sub.2 and sintering at about 1200.degree. C. for about 4 hours.

Abstract: Stabilized zirconia refractories comprising fine block crystals of zirconia, having a high bulk density due to their dense texture and a higher bending strength than the conventional calcined zirconia refractories are disclosed. The stabilized electrocast zirconia refractories are obtained by pouring an electrofused melt of a blend of a zirconia-base material and a stabilizing agent into a mold and solidifying the poured melt from its lower portion by cooling the bottom part of the mold forcibly. Also the method for producing the stabilized electrocast zirconia refractories is disclosed.

Abstract: The present invention relates to ZrO.sub.2 -MgO-Al.sub.2 O.sub.3 -SiO.sub.2 ceramic materials having improved thermal stability and corrosion resistant properties. The utilization of these ceramic materials as heat exchangers for gas turbine engines is also disclosed.