Abstract: A ceramic including a first phase having a general formula R1+(x/2)Zr4P6-xSixO24 where R is selected from the group consisting of Ba, Ca, and Sr and 0≦x≦2, wherein the first phase has a volumetric heat capacity (Cp1), and at least 10 weight percent of a second phase having a volumetric heat capacity (Cp2), wherein Cp2>Cp1. The ceramic has a coefficient of thermal expansion from 22° to 1000° C. of −15×10−7/° C. to +15×10−7/° C., a permeability of at least 0.25×10−12 m2, a total porosity of at least 35% by volume, and a median pore diameter of at least 6 micrometers, and a volumetric heat capacity of the solid Cp(solid) of at least 3.15 J/cm3 K.

Abstract: A WC-based composite ceramics sintered body consisting of 40 volume % to 90 volume % of WC including solid-solved oxygen represented by a chemical formula of WCxOy (where 0.005<y/x+y<0.05), with the remainder being partially stabilized ZrO2 and inevitable impurities, wherein partially stabilized ZrO2 includes one or more of stabilizers selected from the group consisting of Y2O3, CeO2 and MgO. A prepared powder of raw material is held in an atmosphere containing oxygen in a temperature range of 200° C. to 600° C. for 0.1 hour to 3 hours to provide WC grains including solid-solved oxygen represented by a chemical formula of WCxOy (where 0.005<y/x+y<0.05). Partially stabilized Zro2 including one or more of stabilizers selected from the group consisting of Y2O3, CeO2 and MgO is used as a phase for filling up the grain boundary of the WC grains.

Abstract: A sensor material for measuring physical parameters capable of configuring a sensor capable of directly measuring a high value of physical parameters such as high stress or high pressure without employing a pressure resistance container. The sensor material for measuring static and dynamic physical parameters includes a matrix made of an electrically insulating ceramic material, and piezoresistance materials which are dispersed in the matrix so as to be electrically continuous to each other.

Abstract: Mixed oxides of cerium oxide and zirconium oxides having a high oxygen storage and high oxygen release rate are disclosed. The mixed oxides are made of polycrystalline particles of cerium oxide and zirconium oxide having a controlled domain structure on the subcrystalline level wherein adjacent domains within a single crystallite have a different ratio of zirconium and cerium. The mixed oxides are prepared by a co-precipitation technique using mixed salt solutions of cerium and zirconium having a solid content of at least 23%, based on an oxide basis.

Abstract: The invention presents an ion conductor with high reliability, that is one of the following perovskite oxides: {circle around (1)} perovskite oxide of the composition BaZr1-xCexO3-p (0<x<0.8); {circle around (2)} perovskite oxide consisting essentially of Ba, Zr, Ce and O, and substantially conducting protons only; {circle around (3)} perovskite oxide of the composition BaZr1-x-yCexMyO3-p (M, O≦x<1,0<y<1, x+y<1) that is a single-phase polycrystal of cubic, tetragonal or orthorhombic crystal structure whose unit cell edges a, b and c (with a≧b≧c) satisfy 0.8386 nm<a<0.8916 nm and b/a≧0.90; {circle around (4)} perovskite oxide of the same composition as in {circle around (3)} that is a single-phase sintered product with a density of at least 96% of the theoretical density; and {circle around (5)} perovskite oxide of the same composition as in {circle around (3)} that is a single-phase sintered product with 1 to 30 &mgr;m granular diameter.

Abstract: Wear resistant member for electronic equipment comprises a zirconium oxide sintered body of which specific resistance is in the range from 1 to 105 &OHgr;·m. A conductivity enhancer of which specific resistance is 10−5 &OHgr;·m or less is compounded to a zirconium oxide sintered body to materialize specific resistance from 1 to 105 &OHgr;·m. For a conductivity enhancer, carbides and nitrides of various kinds of metals can be used. Wear resistant member can be used as a bearing ball, being applied in a rotational driver of electronic equipment such as a magnetic recording device and an optical disk device. Deficiency due to static electricity of electronic equipment is cancelled due to specific resistance that a zirconium oxide sintered body has.

Abstract: The present invention provides a method of making a ceramic filter, by forming a mixture from NZP-forming raw material powders selected from metal oxide sources capable of reacting to form a reaction product comprising an NZP-type phase having the general formula R1+(y/2)Zr4P6−ySiyO24 where 0≦y≦1.0 and R is one or more of the metals Ca, Sr, and Ba, pre-reacted powder having the same general formula, and mixtures thereof; and a precursor additive selected from the group consisting of silica precursor, zirconia precursor, and mixtures thereof; shaping the mixture into a green structure; and, firing the green structure to produce a ceramic filter having an open porosity of at least 35% by volume, a median pore size of at least 8 micrometers and a permeability of at least 0.30×10−12 m2, and being suitable as a diesel particulate filter.

Abstract: A re-usable alumina-magnesia graphite refractory suitably used for a refractory for continuous casting, such as a long nozzle used for pouring a molten metal from a ladle capable of re-use or intermittent use to a tundish, an immersion nozzle used for charging a molten metal from a tundish to a mold and a long stopper for controlling the flow rate of the molten steel; and produced by blending 3 to 60 wt % of magnesia having a particle size of 0.02 to 1.0 mm to a compound comprising mainly alumina and graphite, and kneading, molding, and baking the compound. The raw material compound comprising mainly alumina and graphite can contain spinel or zirconia.

Abstract: The present invention relates to porous calcium zirconate/magnesia composites having a thermally and chemically stable porous structure, which consist of sintered compacts having a fine composite structure stable under high temperatures due to uniformly dispersed equimolar amounts of calcium zirconate [CazrO3] and magnesia [MgO] and controlled grain growth, and a method of producing the same, and the present porous composites are useful as, for instance, a functional material for filtering highly corrosion resistant materials, lightening members used at super-high temperatures, catalyst carriers, insulation or sound-absorbing materials, and the like.

Abstract: An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.

Abstract: Ceramic monoliths are described which exhibit tunable coefficients of thermal expansion from about −5 to −11×10−6° C.−1 near ambient temperatures. These two-phase ceramics, which are fabricated, for example, by reactive sintering of WO3 and ZrO2, consists of a matrix of ZrW2O8 with inclusions of ZrO2 having diameters less than 10 &mgr;m. Additives may increase the density of the monoliths to greater than 98% of the calculated density. Green body densities, pre-sintered particle size distribution, sintering atmosphere, microstructure, and mechanical properties are discussed. These ceramics may be used as substrates for thermally compensating fiber Bragg gratings.

Abstract: A ceramic including a first phase having a general formula R1+(x/2)Zr4P6−xSixO24 where R is selected from the group consisting of Ba, Ca, and Sr and 0≦x≦2, wherein the first phase has a volumetric heat capacity (Cp1), and at least 10 weight percent of a second phase having a volumetric heat capacity (Cp2), wherein Cp2>Cp1. The ceramic has a coefficient of thermal expansion from 22° to 1000° C. of −15×10−7/° C. to +15×10−7/° C., a permeability of at least 0.25×10−12 m2, a total porosity of at least 35% by volume, and a median pore diameter of at least 6 micrometers, and a volumetric heat capacity of the solid Cp(solid) of at least 3.15 J/cm3 K.

Abstract: A metal-zirconium oxide material made by sol-gel techniques from alkoxides including heterometallic alkoxides. The heterometallic alkoxides include zirconium and another metal selected from alkali metals and alkaline earth metal. Optionally, in forming this material, heterometallic alkoxides of zirconium and lanthanide metal may be included during sol-gel processing, as well as mono-metal alkoxides of these metals or zirconium.

Abstract: A zirconia containing ceramic ball is formed of a zirconia containing ceramic material which contains in an amount of not less than 10% by volume the zirconia ceramic phase composed predominantly of zirconium oxide. The size of the largest pore among pores present in a region extending radially from the surface of the ball to a depth of 50 &mgr;m as observed on a polished cross section of the ball taken substantially across the center of the ball is not greater than 3 &mgr;m. The ceramic ball can be manufactured through firing a green body whose relative density is enhanced to not lower than 61% by use of rolling granulation.

Abstract: The present invention is milling media composed of ceramic particles having an average size of 0.1 to 20 mm. The ceramic particles contain a tetragonal zirconia core and a continuous shell on the core comprising cubic zirconia, monoclinic zirconia, spinel or zircon. The present invention is also a method of manufacturing the milling media which includes providing ceramic particles having an average size of 0.1 to 20 mm. The ceramic particles are tetragonal zirconia. The ceramic particles are coated with a clay material and sintered to form a shell of cubic zirconia, monoclinic zirconia, spinel or zircon over the tetragonal zirconia core.

Abstract: A method is provided for physical vapor deposition of ceramic thermal barrier coatings and articles made therefrom Impurity levels in conventional yttria stabilized zirconia source materials have caused undesired spitting (eruptions) due to a combined effect of various impurities thereby requiring relatively low evaporation rates to control the level of spitting during the process. The present method provides a high purity source material having a purity index sufficiently low to result in reduced spitting in the vapor deposition process and to permit in evaporation rates. Reducing the density of the source material has also been found to reduce spitting. The method permits higher processing rates and/or reduced levels of spitting.

Abstract: The present invention discloses novel magnesia-spinel refractory compositions and bricks formed thereof that exhibit longer lining life, greater hot strength and reduced tendency to spall under high thermal loading conditions. The invention is designed to slow or retard the reaction between spinel and lime through the addition of zirconia in the form of an alumina-zirconia grain to the refractory mix. Zirconia reacts more readily with the lime in the refractory composition and surrounding environment to form calcium zirconate.

Abstract: A ceramic composite material comprises a ceramic material constituting a matrix, and dispersion particles disposed in the matrix in a dispersing manner. A specific shape of a ceramic composite material is, for instance, a sinter or a thermally sprayed layer. The dispersion particles are consisting of a composite oxide including at least one kind of a first metallic element selected from alkaline earth metals such as Mg and Ca, and at least one kind of a second metallic element selected from W, Ti, Ta, Mo, Nb, V, B, Te, Ge and Si, for instance, are composite oxide particles precipitated by reacting a compound containing a first metallic element and a compound including a second metallic element through heat treatment. The precipitated particles consisting of such a composite oxide can be dispersed as planar particles or acicular particles in the ceramic layer to which, for instance, thermal spraying is applied.

Abstract: Disclosed are certain catalysts and catalyst support materials and processes for the preparation of the catalyst support materials and for the selective hydrogenation of 3,4-epoxy-1-butene (EpB) to 1,2-epoxy-butane (butylene oxide—BO). The catalyst support materials have micropores filled with one or more inorganic oxides and the supported catalysts comprise one or more Group VIII metals deposited on the support materials. The rhodium-containing supported catalysts are especially useful for the selective hydrogenation of EpB to BO.

Abstract: The production of open-celled porous inorganic sintered products comprises the stepsa) introducing a flowable mixture comprising an aqueous polymer dispersion, sinterable inorganic powder and dispersant into a precipitation bath in which the polymer precipitates or coagulates to form a non-flowable product comprising polymer, inorganic powder and dispersant,b) removing the product from the precipitation bath and drying the product,c) heating the product to remove polymer and dispersant and sintering the product.The porous open-celled sintered products comprising sintered inorganic powder have a pore volume of from 50 to 95%, a surface area of from 0.1 to 50 m.sup.2 /g and an at least bimodal pore size distribution having maxima in the ranges from 0.02 to 5 .mu.m and from 20 to 500 .mu.m.

Abstract: Ceramic guide rails for guiding photographic film into a perforating machine are disclosed. The ceramic includes zirconium oxide and yttria in a molar ratio of yttria to zirconium oxide of from about 3:97 to about 5:95. The zirconium oxide is essentially the tetragonal phase crystal grain. In an alternate embodiment of the present invention the outer surface of the zirconium oxide is altered to the cubic phase crystal grain or the monoclinic crystal grain.

Abstract: The present invention provides a ceramic sintered body excellent in oxidation resistance under high temperatures and markedly superior to the conventional ceramic sintered body in the mechanical strength over a wide temperature range of between room temperature and 1,500.degree. C. The ceramic sintered body of the present invention comprises at least one ceramic crystal grain selected from the group consisting essentially of a monosilicate represented by the general formula RE.sub.2 SiO.sub.5, where RE denotes a IIIa group element including yttrium, and a disilicate represented by the general formula RE.sub.2 Si.sub.2 O.sub.7, where RE denotes a IIIa group element including yttrium, and at least one additional element selected from the group consisting of Al, Cr, Hf, Nb, Zr, Ti, V, Ta, Ca and Mg which is segregated in the boundaries of the ceramic crystal grains in an amount of 0.1 to 15% by weight of the sintered body in terms of the oxide thereof.

Abstract: The present invention is ceramic article of stabilized zirconia wherein the stabilized zirconia has a molar ratio of rare earth oxide:zirconia of from 1:99 to 15:85, at a weight percent of from about 97 to 75. The ceramic article includes smectite clay from about 3 to 25 weight percent wherein the article is a mass of sintered particles having a continuous tetragonal phase having dispersed therein monoclinic phase particles having size of less than 100 nm.

Abstract: A zirconia diaphragm structure, and a method of producing such structure in which the zirconia diaphragm structure includes a zirconia substrate having at least one window, and a zirconia diaphragm plate formed integrally with the zirconia substrate so as to close each window, the zirconia substrate comprising a zirconia material as a major component, and containing 0.1-3.0% by weight of alumina, 0.1-3.0% by weight of silica, 0.1-5.0% by weight of alumina and silica, 0.1-5.0% by weight of alumina and magnesia, or 0.1-5.0% by weight of alumina, silica and magnesia.

Abstract: Disclosed are a ceramics sheet which has an area of 400 cm.sup.2 or more, thickness of 0.4 mm or less, maximum waviness height of 100 .mu.m or less, and warp of 0.1% or less and in which frequency of generated cracking and breakage is 10% or less when a load-applying test and a deflection-loading test each described in the text are carried out in succession, and a flat and large ceramics sheet having an area of 600 cm.sup.2 or more and thickness of 1 mm or less.

Abstract: A sintered ceramic body which can be worked by electrical discharge machining, has high mechanical strength, and can be worked into sintered ceramic tools which have long life is disclosed. Further, sintered ceramic tools which have long life and scarcely cause flaws in work pieces are provided. The sintered ceramic body comprises ceramic particles having specific particle diameter and particle distribution.

Abstract: Disclosed is a sintered piezoelectric ceramic which is resistant to the high voltage for polarization with no dielectric breakdown and has good moisture resistance. When a plurality of the ceramics are fired, they are prevented from being fused and combined together. The production costs of the ceramic are low. The sintered piezoelectric ceramic comprises particulate or agglomerate zirconia grains dispersed in piezoelectric ceramic grains, in which the mean grain size of the piezoelectric ceramic grains is smaller than that of the zirconia grains.

Abstract: A ceramic green sheet includes ceramic particles having a spherical diameter of 0.01-0.5 .mu.m of a primary particle as a ceramic component, an average degree of aggregation of 10 or less, wherein the ceramic green sheet contains at most 1 vol % of secondary particles having a diameter of 20 .mu.m or more and has a surface roughness (Ra) of 0.2 .mu.m or less. A method for producing a ceramic substrate having a thickness of 30 .mu.m or less includes the steps of: preparing a ceramic slurry by mixing a ceramic powder with an organic binder and at least one organic solvent, and adjusting a viscosity to be within the range of 100-10,000 mPa.s; removing coarse aggregated particles from the ceramic slurry; molding the ceramic slurry into a ceramic green sheet by a reverse roll coater method; and firing the ceramic green sheet so that an average crystal grain size be 2 .mu.m or less.

Abstract: A method for preparing aerogel thin films by an ambient-pressure, continuous process. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.

Abstract: A ZrO.sub.2 -containing glass ceramic is described, the main crystalline phase of which is formed by ZrO.sub.2 and which has at least one further crystalline phase, and which can be used in particular in dentistry.

Abstract: A sintered ceramic body which can be worked by electrical discharge machining, has high mechanical strength, and can be worked into sintered ceramic tools which have long life is disclosed. Further, sintered ceramic tools which have long life and scarcely cause flaws in work pieces are provided. The sintered ceramic body comprises ceramic particles having specific particle diameter and particle distribution.

Abstract: An improved materials transporting element useful for transporting materials in sliding contact with a ware plate, for instance in materials feeder equipment, has a high precision, durable, wear and abrasion resistant sliding surface. The transporting element may have a tetragonal zirconia polycrystal ceramic sliding surface for reciprocal sliding contact with the ware plate having a zirconia-alumina sliding surface. Alternatively, the transporting element may have a zirconia-alumina ceramic composite sliding surface with the ware plate having a tetragonal zirconia polycrystal ceramic sliding surface.

Abstract: An object of the present invention is to provide a novel ceramic composite that has not only excellent dynamic characteristics, but also good electromagnetic characteristics, typified by dielectric characteristics, and the present invention relates to a ceramic composite, characterized in that an oxide having a perovskite structure which includes as raw materials lead and/or an alkaline earth metal is dispersed in a ceramic matrix, and in the above-mentioned ceramic composite, preferably the ceramic matrix is MgO, MgAl.sub.2 O.sub.4, or ZrO.sub.2, and also, preferably in the above-mentioned ceramic composite, the perovskite structure oxide particles are covered with MgO, MgAl.sub.2 O.sub.4, or ZrO.sub.2, and the ceramic matrix is Al.sub.2 O.sub.3.

Abstract: A ZrO.sub.2 based ceramic material having excellent mechanical strength and fracture toughness comprises a first phase of ZrO.sub.2 grains containing CeO.sub.2 as a stabilizer and having an average grain size of 5 .mu.m or less, a second phase of Al.sub.2 O.sub.3 grains having an average grain size of 2 .mu.m or less, and a third phase of elongated crystals of a complex oxide of Al, Ce, and one of Mg and Ca. At least 90 vol % of the first phase is composed of tetragonal ZrO.sub.2. An aluminum (Al) content in the ceramic material is determined such that when Al of the complex oxide is converted to Al.sub.2 O.sub.3, a total amount of Al.sub.2 O.sub.3 in the ceramic material is within a range of 0.5 to 50 vol %. A content of the third phase in the ceramic material is determined within a range of 0.5 to 5 by area %. It is preferred that fine Al.sub.2 O.sub.3 grains having an average grain size of 1 .mu.m or less of the second phase are dispersed within the ZrO.sub.2 grains at a dispersion ratio of at least 2%.

Abstract: A zirconia material resistant to low temperature degradation and process for manufacturing thereof includes heat treating zirconia material or zirconia composite material at 1200.degree.-1700.degree. C. in the presence of nitrogen source.

Abstract: The present invention is a sintered ceramic article having an elemental composition including Zr, O, and at least one element selected from the group consisting of Mg, Ca, Y, Sc, Ce and rare earth elements. The ceramic article includes a core and a casing. The casing is exterior to and continuous with the core. The core is a mass of sintered particles having an essentially tetragonal zirconia crystalline structure and the casing is a mass of sintered particles having a mixture of monoclinic zirconia crystalline structure and zircon crystalline structure.

Abstract: An alumina ceramic article and a method for preparing the article. The method comprises the steps of:(1) Compacting a mixture of a first concentration of particulate aluminum oxide sufficient to prevent retention of the zirconium oxide alloy particles in the surface in a predominantly tetragonal crystal structure and a second concentration of particulate zirconium oxide alloy. The zirconium oxide alloy is zirconium oxide and a secondary oxide selected from the group consisting of MgO, CaO, Y.sub.2 O.sub.3, Sc.sub.2 O.sub.3, CeO.sub.2, and rare earth oxides having a concentration of secondary oxide generally of about 0.5 to about 5 mole percent Y.sub.2 O.sub.3, from about 0.1 to about 1 mole percent MgO, from about 0.5 to about 15 mole percent CeO.sub.2, from about 0.5 to about 7.0 mole percent Sc.sub.2 O.sub.3, or from about 0.5 to about 5 mole percent CaO, relative to the total of the zirconium oxide alloy. The compacting results in the formation of a blank.

Abstract: An electrochemical process for producing unsaturated hydrocarbon compounds from unsaturated hydrocarbon compounds and for extracting oxygen from a gas containing N.sub.2 O, NO, NO.sub.2, SO.sub.2, or SO.sub.3 is described. The process is characterized by the use of mixed metal oxide materials having a perovskite structure represented by the formula:A.sub.s A'.sub.t B.sub.u B'.sub.v B".sub.w O.sub.xwherein A represents a lanthanide or Y, or a mixture thereof; A' represents an alkaline earth metal or a mixture thereof; B represents Fe; B' represents Cr or Ti, or a mixture thereof; and B" represents Mn, Co, V, Ni, or Cu, or a mixture thereof.

Abstract: A novel ceramic substrate useful for the preparation of superconductors, said substrate having the formula Ba.sub.2 DyMO.sub.5.5 where M represents at least one of the metals Zr, Sn and Hf and a process for the preparation of said ceramic substrate, which comprises (i)Reacting salts of dysprosium, barium and Zr, Sn or Hf in an organic medium, (ii) Pressing the resultant mixture in the form of pellets, (iii)Calcining the pellets by heating at a temperature in the range of 1000.degree. to 1200.degree. C., (iv)Repeating the calcination process for 30-45 h at temperature in the range of 1000.degree.-1200.degree. C. until a highly homogenous mixture is formed, (v)Grinding the calcined material and pelletizing at a pressure in the range of 3 to 4 tons/cm.sup.2, (vi) Sintering the resultant product at a temperature in the range of 1200.degree. to 1600.degree. C. for a period of 10 to 30 h, and then furnace cooled to room temperature.

Abstract: The invention is directed to a non-vapor phase process for forming a metal/ceramic composite containing a relatively inert metal such as silver, copper, or nickel by the reaction of a reactive metal or metal alloy containing the inert metal, and a sacrificial ceramic preform. The resulting metal/ceramic composite is essentially the same shape and dimensions as the sacrificial ceramic preform, and exhibits improved physical and mechanical properties, including improved corrosion and wear resistance.

Abstract: The present invention is a ceramic article of magnesium-X silicate, wherein X represents lithium, sodium, potassium or other monovalent ion from about 0.1 to 2 weight percent, and yttria stabilized zirconia and alumina composite from about 99.9 to 98 weight percent wherein the yttria stabilized zirconia has a molar ratio of yttria to zirconia of from 0.5:99.5 to 5:95 and the alumina comprises from 0.1 to 50 percent of the yttria stabilized zirconia and alumina composite.

Abstract: The present invention is a ceramic article of magnesium-X silicate, wherein X represents lithium, sodium or, from about 0.1 to 2 weight percent, and yttria stabilized zirconia from about 99.9 to 98 weight percent wherein the yttria stabilized zirconia has a molar ratio of yttria to zirconia of from 0.5:99:5 to 5:95.

Abstract: A process for producing a zirconia beating opacifier is disclosed. The process comprising the steps of: (I) heat treatment of a zirconia bearing material comprising heating the zirconia bearing material in the presence of an additive to form a heat modified product having one or more phases which, when incorporated in a glaze and the glaze fired, exhibit opacifying characteristics; and (ii) cooling the heat modified product to produce a product which can be used for imparting opacity.

Abstract: An electrical discharge machinable MgO-Partially Stabilized Zirconia (PSZ) and titanium di-boride (TiB.sub.2) ceramic composite body of good mechanical properties and the method of making it are disclosed. The ceramic composite comprising less than 40% by weight of TiB.sub.2 balanced by 10 mole % of MgO-Partially Stabilized Zirconia is fully densified by pressureless sintering at 1850.degree. C.-1900.degree. C. and exhibits the fracture toughness (K.sub.IC) value of 8-11 MPa.multidot.m.sup.1/2 measured according to the indentation crack length method and Evans-Charles' method provided in Journal of the American Ceramic Society volume 59 ?7-8!, 371-372 (1976) after annealing at 1320.degree.-1400.degree. C.

Abstract: A method for preparing a ceramic composite having a core/bulk of tetragonal zirconia alloy and a shell/surface comprising zirconium boride by sintering a zirconia or zirconia and alumina composite article in an argon atmosphere while in contact with boron carbide.

Abstract: A process and composition are disclosed for slip casting a ceramic powder in a porous mold. In this invention, a ceramic powder is blended with a polymeric cellulose ether. A slurry of ceramic powder-cellulose ether is formed. A porous mold is coated with a hydrophilic colloid of ammonium alginate to form a treated mold. The slurry is then poured in the treated mold and a slip is formed. This invention is particularly useful for forming crack-free slips made from difficult to cast ceramic powders.

Abstract: High-zirconia fused refractories consist essentially of 85-96 wt % of ZrO.sub.2, 3-8 wt % of SiO.sub.2, 0.1-2 wt % of Al.sub.2 O.sub.3, 0.05-3 wt % of B.sub.2 O.sub.3, 0.05-3 wt % of BaO, SrO and MgO in total, 0.05 wt % or more of Na.sub.2 O, 0.05-0.6 wt % of Na.sub.2 O and K.sub.2 O in total, and 0.3 wt % or less of Fe.sub.2 O.sub.3 and TiO.sub.2 in total, and does not substantially contain P.sub.2 O.sub.5 and/or CuO.

Abstract: A method for preparing a ceramic article comprising compacting a particulate alloy of a primary oxide and a secondary oxide to form a blank, and sintering the blank in contact with substantially pure zirconium oxide. The primary oxide is zirconium oxide and 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. Ceramic articles produced have tetragonal phase cores and monoclinic cases.

Abstract: A method for preparing a ceramic article comprising compacting a particulate alloy of a primary oxide and a secondary oxide to form a blank, and sintering the blank in contact with substantially pure zirconium oxide. The primary oxide is zirconium oxide and 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. Ceramic articles produced have tetragonal phase cores and monoclinic cases.

Abstract: A zirconia-based sinter containing a boron compound and stabilized with a rare earth metal oxide is provided which has excellent fracture toughness, mechanical strength and thermal stability. A zirconia-based sinter comprising ZrO.sub.2 as the main component, one or more rare earth metal oxides, R.sub.2 O.sub.3, selected from Yb.sub.2 O.sub.3, Er.sub.2 O.sub.3, Ho.sub.2 O.sub.3, Y.sub.2 O.sub.3, and Dy.sub.2 O.sub.3, and a boron compound or a boron compound and Al.sub.2 O.sub.3 and/or SiO.sub.2, wherein the molar proportion of R.sub.2 O.sub.3 /ZrO.sub.2 is from 1.3/98.7 to 2/98, excluding 2/98, and the content of boron components is from 0.05 to 8% by mole in terms of B.sub.2 O.sub.3 or in addition thereto the content of Al.sub.2 O.sub.3 is from 0.1 to 5% by mole and/or the content of SiO.sub.2 is from 0.05 to 1.5% by mole. A grinding part material and a bracket material for dental correction constituted of the zirconia-based sinter are provided.