Abstract: An evaporation material is employed to form an optical thin film which is adapted to be formed on an optical element such as a lens or the like. The evaporation material is provided such that zirconium oxide (ZrO.sub.2) is mixed with a titanium oxide (TiO.sub.A) having a molar ratio A(O/Ti) of oxygen to titanium in a range of 1.0 to 1.75 so that the mixture assumes a molar ratio (Ti/Zr) of titanium to zirconium in a range of 1.0 to 4.0. The mixture is sintered or fused and solidified.

Abstract: The present invention pertains to a refractory ceramic mass, consisting of a pure magnesia component A and a component B, which consists of granules of pure magnesia, wherein the magnesia granules of component B have a ceating consisting of a refractory material whose granule size is fine compared with that of the magnesia granules and is chemically extensively inert with respect to the magnesia granule or reacts with the magnesia granule and/or itself consists of a plurality of components that are chemically reactive with one another.

Abstract: A process is described for the production of alumina/zirconia materials which uses cheap scrap alumina/zirconia/silica material as feedstock along with a reducing agent to lower the final silica content to an acceptable level.

Abstract: A refractory powder includes a filler, a binder, and a metal powder. This provides improved heat transfer in the refractory material during heating, and reduces the problem of explosive cracking and spalling so the refractory material can be burned out at substantially constant temperature, thereby saving considerable amounts of time and energy.

Abstract: A sintering ceramic for stable high-temperature thermistors includes a system of matter containing manganese (IV) and a content of a basic oxide. A method for producing a sintering ceramic for stable high-temperature thermistors includes calcining a mixture of SrCO.sub.3 and Mn.sub.2 O.sub.3 or Mn.sub.3 O.sub.4 ; adding an oxide hydroxide of a dopant in a molar quantity x to an aqueous suspension of the calcined oxide mixture; and then carrying out a compacting densification of the system of matter.

Abstract: A method of preparing a mixture of zirconia and a stabilising agent for the zirconia comprises milling an aqueous suspension of particulate zirconia and particulate stabilising agent in a bead mill for at least 2 minutes in the presence of a particulate mixing medium having an average particle size from 0.2 mm to 3 mm. Preferred stabilising agents are oxides of yttrium, cerium, calcium or magnesium. Surprisingly, ceramics prepared from the product mixture are more resistant to degradation by attack from water above 100.degree. C. than are ceramics prepared from coprecipitated powders.

Abstract: A molten steel pouring nozzle having, along the axis thereof, a bore through which molten steel flows. At least part of an inner portion of the molten steel pouring nozzle, which inner portion forms the bore, is formed of a refractory consisting essentially of:zirconia clinker comprising calcium zirconate: from 40 to 64.9 wt. %,where, a content of calcium oxide in the zirconia clinker being within a range of from 8 to 35 weight parts relative to 100 weight parts of the zirconia clinker,graphite: from 10 to 35 wt. %, andcalcium silicate: from 25.1 to 50 wt. %,where, a content of calcium oxide in the calcium silicate being within a range of from 40 to 54 weight parts relative to 100 weight parts of the calcium silicate.

Abstract: The invention relates to fused ceramic beads, which have the following chemical composition in % by weight on the basis of the oxides:40 to 95% of ZrO.sub.2 and HfO.sub.2 ;at least one of Y.sub.2 O.sub.3 and CeO.sub.2, with the provisos that Y.sub.2 O.sub.3, when present, represents 0.1 to 10% and CeO.sub.2, when present, represents 1 to 25%, the total of Y.sub.2 O.sub.3 and CeO.sub.2 representing 0.1 to 25%;a quantity of SiO.sub.2 representing 10 to 45% of the composition when CeO.sub.2 is absent from the composition and 0.5 to 45% when CeO.sub.2 is present in the composition. Application to grinding and to dispersion in wet medium is provided.

Abstract: The present invention relates to non-magnetic ceramic substrate material for magnetic head having similar thermal expansivity to the metal magnetic thin film, abrasion resistance during contact traveling of the magnetic tape and good processability and thus increasing lifetime by preventing exfoliation and crack of the magnetic thin film. The material comprises 10-35 mol % of CaO, 10-40 mol % of TiO.sub.2, 10-60 mol % of NiO and 10-50 mol % of CoO.

Abstract: Three families of ceramic compositions having the given formula: .phi..sub.1+X Zr.sub.4 P.sub.6-2X Si.sub.2X O.sub.24, .phi..sub.1+X Zr.sub.4-2X Y.sub.2X P.sub.6 O.sub.24 and .phi..sub.1+X Zr.sub.4-X Y.sub.X P.sub.6-2X Si.sub.X O.sub.24 wherein .phi. is either Strontium or Barium and X has a value from about 0.2 to about 0.8 have been disclosed. Ceramics formed from these compositions exhibit very low, generally near neutral, thermal expansion over a wide range of elevated temperatures.

Abstract: A novel ceramic ferroelectric material having a low dielectric constant, loss and high tunability. The material is a composite comprising Barium Strontium Titanate (BSTO) and a ceramic material having a low dielectric constant. The preferred composite is represented by Ba.sub.1-x Sr.sub.x TiO.sub.3 --ZrO.sub.2, wherein x is greater than 0.00, but less than or equal to 0.70, and wherein the percent weight ratio between Ba.sub.1-x Sr.sub.x TiO.sub.3 and ZrO.sub.2 ranges from approximately 99%-40% and 1%-60%, respectively. The novel materials possess superior electronic properties; and they may be employed in various antenna systems.

Abstract: The invention relates to the thermal barriers, to a process and material for their production, and to their application. Thermal barriers consist of a material comprising at least one refractory oxide with low thermal diffusivity and at least one quasicrystalline aluminum alloy, the proportion of which represents from 2-30% by volume. They can be produced by deposition of a mixture of refractory oxide and of quasicrystalline alloy in vapor phase, or from a mixture of refractory oxide and quasicrystalline aluminum alloy in the molten state, or else by deposition onto the support to be protected with the aid of an oxygen-gas torch fed with material using a flexible cord which contains the refractory oxide and the quasicrystalline alloy. The applications include the protection of components of aircraft or motor vehicle engines, of aeronautical or aerospace components, of chemical reactors or of electrical households appliances.

Abstract: A material for a magnetic head slider consists essentially of 0.1 to 20.0 vol % of at least one of oxides the group Va elements of the International Periodic Table (Ta, Nb, V) and 80.0 to 99.9 vol % of stabilized cubic ZrO.sub.2 containing a stabilizer (Y.sub.2 O.sub.3, MgO, CeO.sub.2). It has improved precision machinability, machining efficiency, high strength, densified structure, affinity with the recording medium or lubricity, besides wear resistance. It may be machined precisely into a thin film magnetic head slider with a reduced amount of chipping.

Abstract: Partially stabilized zirconia is disclosed which contains yttrium oxide; an MgO ingredient in the grain boundaries; and the remainder being zirconium oxide and unavoidable impurities. Preferably a critical temperature difference of the partially stabilized zirconia is larger than or equal to 340.degree. C.The partially stabilized zirconia may be suitably used as a solid electrolyte body in an electrochemical device with at least a pair of electrodes.An MgO ingredient and, preferably an Al.sub.2 O.sub.3 and a SiO.sub.2 ingredients as well are believed to be present in the grain boundary in the partially stabilized zirconia and responsible for excellent thermal shock resistance.

Abstract: A refractory mix made comprising magnesite having an MgO content of at least about 95 wt. % and fused spinel-zirconia grain comprising 1 to 40 wt. % zirconia and refractory shapes, particularly brick, made therefrom.

Abstract: A solid composition provides high oxygen ion conductivity, and includes a metal oxide combined with multiple dopants. The oxide may, for example, include zirconia, bismuth trioxide, thoria or hafnia. The dopants are chosen such that they are of similar ionic radius to the oxide, but such that they generally have different valences. For example, zirconium has a +4 valence, while dopants are usually chosen which have +2 or +3 valences. Possible dopants include materials such as magnesia, yttria, and oxides of calcium, barium, strontium, lanthanum, ytterbium, and scandium. It has been found that choosing the dopants such that they exist in the composition at specified ratios results in surprising ability to transport oxygen ions. In the case of a composition which includes magnesia and yttria dopants placed within a zirconia matrix, it has been found desirable to maintain the ratio of the mole percentages of the magnesia to the yttria in the range of from about 5.75:10 to about 11:10.

Abstract: A method for preparing a ceramic article comprising compacting a particulate including a primary oxide and a secondary oxide to form a blank. The primary oxide is ZrO.sub.2. The secondary oxide is selected from the group consisting of MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, rare earth oxides and combinations thereof. The blank is sintered in contact with oxide selected from the group consisting of MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3 and rare earth oxides. The zirconia alloy ceramic articles produced have a cubic phase case and a tetragonal phase core.

Abstract: A zirconia ceramic having a tetragonal phase crystal grain structure and a process for producing same. The ceramic comprises zirconium oxide and a dopant that is an oxide of a rare earth element, calcium, or magnesium, or mixtures thereof, and the ceramic has a molar ratio of dopant to zirconium oxide in the range of from above about 3:97 to about 5:95 when the ceramic comprises less than about 0.5 mole percent of the oxide of magnesium, the ceramic has a molar ratio of dopant to zirconium oxide in the range of from about 0.5:99.5 to about 1.0:99.0 when the ceramic comprises from about 0.5 mole percent to about 1.0 mole percent of the oxide of magnesium, and the ceramic does not comprise more than about 1.0 mole percent of the oxide of magnesium.

Abstract: A corrosion and erosion resistant, high strength refractory composition suitable for use as a slide gate valve plate or insert for such plates. The mix for the composition comprises in weight per cent about 87-90 high purity, partially stabilized zirconia; 4-5 silicon metal; 3-12 alumina, 3-5 graphite and 4-7 carbonaceous binder. The mix is pressed to a desired shape and fired in a reducing atmosphere at a temperature in excess of 1000.degree. C. to produce a carbon bonded shape. High purity magnesia and high purity yttria, partially stabilized zirconia materials are employed in the mix to obtain superior hot strength properties.

Abstract: A known relatively dense composite refractory material has a matrix of a refractory material and a dispersed phase in the form of particles of a ceramic material, each dispersed particle comprising an agglomerate of strongly bonded microcrystals, which exhibit strong thermal expansion anisotropy and do not crack spontaneously on cooling from about 1600.degree. C. to ambient temperature. The thermal shock resistance of this composite refractory material is improved by (a) ensuring that the matrix material comprises from 5 to 90 percent by volume of grains having a diameter in the range of from 15 micrometers to about 80 micrometers, and/or (b) including at least one thermal down-quench of from 50.degree. C. to 1500.degree. C. in the final cooling step in the production of the composite refractory material. Alumina is a typical matrix material, with monoclinic zirconia as the dispersed phase.

Abstract: The present invention provides a zirconium oxide-containing ceramic formed body, wherein it is also free from amorphous phases on the grain boundaries and triple points, displays a shrinkage of less than 5% in comparison with its green body and is obtainable by reaction sintering of a green body, said ceramic formed body being formed from a mechanically alloyed mixture which contains or consists of at least 1% by volume zirconium metal powder and at least 20% by volume of one or more metallic powders selected from the elements magnesium, aluminum, copper, selenium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc, strontium, yttrium, niobium, cerium, hafnium and tantalum, as well as the oxides thereof and zirconium oxide, sodium oxide, potassium oxide and lithium oxide.

Abstract: A thermal spray powder feed coating composition composed of stabilized zirconia mixed with zircon and a selected oxide, such as yttria, to form a refractory oxide coating ideally suited for hearth rolls for annealing steel Process for producing the coating and the coated article so produced is also disclosed.

Abstract: A sintered body where alumina is dispersed in a zirconia matrix in which yttria has been doped to form a solid solution can be obtained by compacting a mixed powder comprising zirconia or yttria-stabilized zirconia and yttrium-aluminum complex oxide and sintering the resulting compacted body. This sintered body comprises a fine zirconia matrix in which fine alumina particles are dispersed to strengthen it and is excellent in flexural strength and fracture toughness and has a practically effective oxygen ionic conductivity.

Abstract: A method for preparing a ceramic article comprising compacting a particulate including a primary oxide and a secondary oxide to form a blank. The primary oxide is ZRO.sub.2 and the secondary oxide is MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, rare earth oxides or a combination thereof. The blank is sintered in contact with MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, rare earth oxides or a combination thereof. The zirconia alloy ceramic articles produced have a cubic phase case and a tetragonal phase core.

Abstract: A nonmagnetic oxide substrate material has a composition of 15 to 60 mol % of NiO, 10 to 70 mol % of CoO, 10 to 40 mol % of TiO.sub.2, and 0.5 to 25 mol % of CaO and is formed of very minute crystal grains. Preferably MgO or ZrO.sub.2 is used as an additive to the material to present a total composition containing the additive of 0.5 to 3 wt % per 100 parts by weight of the nonmagnetic oxide substrate material. Preferably, the substrate material is formulated to have a thermal expansion coefficient falling in the range of from 100 to 140 X 10.sup.-7 /.degree.C. A magnetic head using this substrate material reduces the loss in surface smoothness due to the relative slide with the magnetic tape.

Abstract: A refractory composition, particularly for application as a dry vibratable refractory for forming the wearable, disposable monolithic lining coating the permanent lining of a tundish or ladle used in molten metal casting processes is disclosed. The composition contains a refractory aggregate, a first bonding agent actuatable at temperatures in the range of from about 300.degree. F. to about 1000.degree. F. to cause the formation of interparticle bonds between aggregate particles, at least one second bonding agent actuatable at temperatures in the range of from about 1000.degree. F. to about 2500.degree. F. to cause further formation of interparticle bonds between aggregate particles, and, optionally, clay. The use of both first and second bonding agents enables installation of the refractory in hot practice, in which vessel preheat temperatures of up to about 2500.degree. F. are utilized.

Abstract: A zirconia ceramic composed of crystals which scarcely undergo phase transformation from tetragonal system to monoclinic in the temperature range of from 100.degree. C. to 300.degree. C. even in the presence of water vapor or water is disclosed, said zirconia ceramic comprising at least 93% by weight of partially stabilized zirconia mainly composed of tetragonal crystals and containing mainly Y.sub.2 O.sub.3 and ZrO.sub.2 at the former to the latter molar ratio of from 2/98 to 4.5/95.5 and balance of at least one of the oxides selected from the group consisting of boron oxide, germanium oxide, and gallium oxide, wherein the content of the boron oxide is 1% by weight or less.

Abstract: A process for producing dense-sintered cordierite bodies and zirconium dioxide-reinforced cordierite bodies with a maximum of 50% by weight of ZrO.sub.2 is described, wherein a powder of cordierite particles of stoichiometric composition and, if appropriate, ZrO.sub.2 of a particle size of less than 3 .mu.m is heated at temperatures above 800.degree. C. at a rate of temperature rise of less than 5.degree. C. per minute. Virtually pore-free sintered bodies having outstanding mechanical properties can be produced by the process.

Abstract: A heat resistive phosphate sintered body including a solid solution of R.sub.y Zr.sub.4 Si.sub.x P.sub.6-x O.sub.24 in which O.ltoreq.x.ltoreq.2, 2/3.ltoreq.y.ltoreq.2, R is a combination of one or more of cations having 2-3 valences, and x and y meet an electrically neutral condition, wherein a thermal expansion hysteresis loss is not more than 0.3%, and a dimensional change after a heat cycling in which heating and cooling are repeated between 100.degree. C. and 1,200.degree. C. at 100 times is not more than 1%. A process for producing such a heat resistive phosphate is also disclosed. The process includes the steps of preparing a batch mixture, as a starting material, of (ZrO).sub.2 P.sub.2 O.sub.7, ZrP.sub.2 O.sub.7, RO and/or a phosphate of R in which R is a combination of one or more of cations having two or three valences, and if necessary further SiO.sub.2, calcining, milling and shaping the thus prepared mixture, and firing the thus shaped body, wherein a calcining temperature is not less than 1,400.

Abstract: Crystalline zirconium oxide powder with a BET surface of less than 30 m.sup.2 /g, preferably 10 to 20 m.sup.2 /g, a primary particle size of 0.1 to 0.5 .mu.m, a monoclinic crystal structure and, optionally, a content of Y.sub.2 O.sub.3 of 1 to 10% by weight and/or of 1 to 10% by wt. MgO.It is produced by adding an aqueous zirconium salt solution optionally containing yttrium ions and/or magnesium ions under agitation into a vessel which contains an aqueous base solution such as e.g. sodium hydroxide solution with a content of NaOH which corresponds to an excess of at least 0.5 mole/l NaOH. The mixture obtained in this manner is then treated hydrothermally at a temperature of 200.degree. to 400.degree. C., the product obtained is separated by filtration, washed chloride-free with water and dried at 100.degree. to 120.degree. C.The zirconium oxide powder can be used to produce sintered ceramics.

Abstract: Ceramic binder for forming and processing ceramic ware, comprising a sol-gel of a mixture of highly charged metal hydroxy cations and one or more low charged metal hydroxy cations, which are able to form an aqueous sol.

Abstract: A molten steel pouring nozzle having, along the axis thereof, a bore through which molten steel flows. At least part of an inner portion of the molten steel pouring nozzle, which inner portion forms the bore, is formed of a refractory consisting essentially of:______________________________________ zirconia clinker comprising calcium from 40 to 89 wt.%, zirconate where, a content of calcium oxide in the zirconia clinker being within a range of from 6 to 35 weight parts relative to 100 weight parts of the zirconia clinker; graphite from 10 to 35 wt.%, and crystal stabilized calcium silicate from 1 to 30 wt.%. comprising dicalcium silicate (2CaO.SiO.sub.2) and tricalcium silicate (3CaO.SiO.sub.

Abstract: An electrically conductive material for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO.sub.2 as a matrix and 6-19 wt. % monoclinic ZrO.sub.2 formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO.sub.2 as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns.

Abstract: Zirconia sols are prepared by hydrolyzing zirconium alkoxides by aqueous hydrogen peroxide in the presence of an acid, evaporating the hydrolysates to dryness, and redispersing the dried hydrolysates in an organic solvent and the sols can be used for the preparation of zirconia forms in a desired shape satisfactorily on a commercial scale with removal of as much residual carbon as possible and without foaming in the gelation and molding steps.

Abstract: The present invention relates to a process for producing an inorganic biomaterial, according to which, there can be obtained an inorganic biomaterial excellent in strength and biocompatibility, having a structure in which portions constituted by crystallized glass or crystals of calcium phosphate excellent in bioactivity are dispersed in a skeleton or matrix constituted by crystals of partially stabilized zirconia and/or alumina showing high strength. Accordingly, the inorganic biomaterial is very useful as biomaterial for artificial bones, dental implants, etc.

Abstract: A near infrared screening filter glass consisting essentially of from 35 to 60 wt. % of P.sub.2 O.sub.5, from 10 to 30 wt. % of Al.sub.2 O.sub.3, from 1.5 to 15 wt. % of SiO.sub.2, from 3 to 15 wt. % of B.sub.2 O.sub.3 and from 0.1 to 10 wt. % of CuO.

Abstract: A dielectric ceramic composition possessing a high relative dielectric constant, a high unloaded Q, and an excellent temperature characteristic is expressed as xPbO-yZrO.sub.2 -zCaO, in the relation of x+y+z=1, wherein x, y, z are in mol percentage ranges of 0.125.ltoreq.x.ltoreq.0.49, 0.4.ltoreq.y.ltoreq.0.6, 0.11 .ltoreq.z.ltoreq.0.275. A part of ZrO.sub.2 of the composition formula may be replaced by (B1B2)0.sub.2 (where B1 is Mg, Ca, Zn, Co, Ni, Mn, Cu, Al, Ga, or Y, and B2 is Nb, Ta, or W), or Sn.

Abstract: An ivory-colored zirconia sintered body having high toughness, high mechanical strength and aesthetical excellence, a process for its production and its use as a bracket for orthodontic application; the sintered body containing stabilizer-containing ZrO.sub.2 as a main component, and also containing, based on the stabilizer-containing ZrO.sub.2, 0.05 to 1.0 mol % of Er.sub.2 O.sub.3, 0.0001 to 0.05 mol % of Pr.sub.6 O.sub.11, 0.0001 to 0.3 mol % of Fe.sub.2 O.sub.3 and 0.05 to 0.

Abstract: A heat resistive phosphate-zircon composite body including a main crystalline phase and a secondary crystalline phase, the main crystalline phase being a solid-solved phase of R.sub.y Zr.sub.4 Si.sub.x P.sub.6-x O.sub.24 in which 0<x<2, 2/3<y<2, and R includes of one or more kinds of bivalent or trivalent cations (provided that x and y satisfy electrical neutrality), and the secondary crystalline phase being zircon. A process for producing a heat resistive phosphate-zircon composite body is also disclosed. The process includes the steps of measuring and mixing given amounts of ZrP.sub.2 O.sub.7, (ZrO).sub.2 P.sub.2 O.sub.7, RO and/or a phosphate of R, SiO.sub.2 and a zircon powder, shaping the mixture and firing the shaped body, wherein the given amounts of ZrP.sub.2 O.sub.7, (ZrO).sub.2 P.sub.2 O.sub.7, RO and/or the phosphate of R, and SiO.sub.2 are measured such that the composite body may include a main crystalline phase composed of a solid-solved phase of R.sub.y Zr.sub.4 Si.sub.x P.sub.

Abstract: A process is presented for the fabrication of a metal/ceramic composite by a non-vapor phase oxidation of a molten metal by contacting said molten metal at an elevated temperature with a sacrificial ceramic preform. The shape of the preform is retained but the ceramic preform is reduced, oxidizing the molten metal. A preferred sacrificial ceramic preform is silica, but can also be, for example, mullite, titania or zirconia, and the preferred molten metal is aluminum or an aluminum alloy. Thus, for example, is produced from immersing a silica preform into molten aluminum alloy, an Al/Al.sub.2 O.sub.3 composite metal/ceramic article which does not contain silica or silicon and which is extremely tough.

Abstract: Basic monolithic refractories of which the chemical composition consists essentially of, in oxide equivalence, 65%-96% by weight of MgO, 2.6%-20% by weight of ZrO.sub.2, 1.3-10% by weight of SiO.sub.2, 2% or less by weight of CaO, 0.5% or less by weight of Fe.sub.2 O.sub.3 and 1% or less by weight of Al.sub.2 O.sub.3, and with a mineral composition containing periclase as the main component and cubic zirconia and forsterite as sub-components, and with apparent porosity of 7% or less and bulk density of 3.2 g/cm.sup.3 or more.Basic monolithic refractories under this invention possess excellent slaking resistance, slag erosion resistance, slag penetration resistance and spalling resistance. They exhibit an excellent service life, especially as lining material for steel-making furnaces.

Abstract: An oxide-based strengthening and toughening agent, such as tetragonal Zro.sub.2 particles, has been added to copper oxide superconductors, such as superconducting YBa.sub.2 Cu.sub.3 O.sub.x (123) to improve its fracture toughness (K.sub.IC). A sol-gel coating which is non-reactive with the superconductor, such as Y.sub.2 BaCuO.sub.5 (211) on the ZrO.sub.2 particles minimized the deleterious reactions between the superconductor and the toughening agent dispersed therethrough. Addition of 20 mole percent ZrO.sub.2 coated with 211 yielded a 123 composite with a K.sub.IC of 4.5 MPa(m).sup.0.5.

Abstract: A process for producing a ceramic implant which comprises creating a powder mixture comprising zirconia and .alpha.-tricalcium phosphate or zirconia and hydroxyapatite, in a weight ratio of 0.05 to 20 on the surface of a molded unsintered product of partially stabilized zirconia, followed by sintering at 1200.degree. to 1550.degree. C. The partially stabilized zirconia may have a BET specific surface area of from 5 to 10 m.sup.2 /g and have been subjected to wet pulverization to increase the BET specific surface area from 1.05 to 2.0 times relative to the starting material.

Abstract: A method for producing a ceramic is disclosed. The method involves comminuting a batch composed of from 6 to 95 percent of particulate ZrO.sub.2 and from 5 to 94 percent of particulate Al.sub.2 O.sub.3. A part of the particulate ZrO.sub.2 is in a metastable tetragonal crystal structure, for example, as a consequence of 3.sup.m/o of Y.sub.2 O.sub.3 dissolved therein and a part has a monoclinic crystal structure. The comminuted batch is compacted into a shape, and the shape is fired. The degree of comminution of the batch, the firing conditions and the proportions of stabilized and monoclinic ZrO.sub.2 in the batch are controlled to produce a dense, gas impervious ceramic which contains both metastable tatragonal and monoclinic ZrO.sub.2, and in such proportions that the ceramic has improved strength by comparison with an otherwise identical ceramic wherein all of the ZrO.sub.2 is in either a metastable tetragonal or a monoclinic crystal structure.

Abstract: Fused zirconia refractory materials having high-temperature resistance and corrosion resistance which includes 1-14 30 wt % of calcia and 0.05-2 wt % of yttria or rare earth minerals including yttria as a stabilizer of zirconia, which are produced by the process comprising adding and mixing calcia and yttria or rare earth minerals including yttria to zirconia materials as a stabilizer, fusing the mixed materials in an electric arc furnace, cooling slowly the fused materials to obtain an ingot, crushing the ingot to particles and oxidizing and annealing the particles.

Abstract: A ceramic material suitable for packaging of large scale integrated circuits is produced by the process of forming a mixture of a powdered glass ceramic material which is a glassy precursor to cordierite ceramic material, formed by the steps which are as follows:a. Mix tetragonal phase material selected from the group consisting of zirconia of hafnia powder containing a stabilizing oxide compound selected from the group consisting of MgO, CaO and Y.sub.2 O.sub.3 and a glass frit powder or frit of a glassy precursor of cordierite glass ceramic to yield a suspension of solids. Preferably, a binder is included.b. Disperse the suspended solids to yield a dispersion of the zirconia or hafnia with the stabilizing oxide compound and the glassy precursor.c. Densify the dispersion of zirconia or hafnia with the stabilizing oxide compound and the glassy precursor by a sintering heat treatment at a temperature of about 840.degree. C.

Abstract: A graded electrolyte of zirconia and bismuth oxide containing proposed surface regions one of which is rich in zirconia, the other rich in bismuth oxide is disclosed. The strength and reduction resistance of zirconia is combined with the high ionic conductivity of bismuth oxide to form a superior oxygen ion-conducting electrolyte which is especially useful in fuel cells.

Abstract: Partially stabilized cubic or tetragonal zirconia powder are provided which comprise aggregates of dense equiaxial primary particles, wherein said particles have an average diameter of less than about 150 nm and comprise zirconia and a homogeneously distributed stabilizer, as well as processes for their production employing flame combustion of homogeneous mixtures of ZrCl.sub.4 and stabilizer precursors.

Abstract: A beta alumina sintered body having no tantalum component in an intergranular phase is manufactured by mixing raw materials consisting essentially of 8.0-10.0 wt % of sodium oxide, 3.0-5.5 wt % of magnesium oxide and/or 0.1-2.0 wt % of lithium oxide, 0.01-0.5 wt % of tantalum oxide, and the remainder of aluminum oxide to obtain raw material powders; forming the raw material powders to obtain a formed body; and sintering the formed body.

Abstract: A ceramic consisting essentially of from 1 to 15 percent of glass and 99 to 85 percent of a mixture of particulate Al.sub.2 O.sub.3 and particulate ZrO.sub.2 is disclosed. ZrO.sub.2 is present in a sufficient amount, usually from 1/4 to 6 percent based on the weight of the ZrO.sub.2 and Al.sub.2 O.sub.3, to strengthen the ceramic significantly, by comparison with an otherwise identical ceramic where the particulate ZrO.sub.2 is replaced either by the glass or by particulate Al.sub.2 O.sub.3. The glass constitutes a vitreous phase bonding the particulates into a dense, gas impervious structure, and can be a calcium magnesium silicate glass containing from 45 to 80 percent of SiO.sub.2, from 8 to 55 percent of CaO and MgO, and not more than 15 percent of Al.sub.2 O.sub.3.