Abstract: The invention provides a sintered, yttria stabilized zirconium-toughened alumina ceramic product comprising about 80-94 w/w % Al2O3, about 5-19 w/w % ZrO2 and about 0.18-0.72 w/w % Y2O.

Abstract: The invention provides a fused cast refractory product with a high zirconia content comprising, as. a percentage by weight based on the oxides: ZrO2+Hf2O: >85%; SiO2: 6% to 12%; Al2O3: 0.4% to 1%; Y2O3: 0.2%; a dopant selected from the group formed by Nb2O5, Ta2O5, and mixtures thereof, in a quantity such that the molar ratio ZrO2/(Nb2O5+Ta2O3) is in the range 200 to 350.

Abstract: Dental articles are produced using relatively low sintering temperatures to achieve high density dental articles exhibiting strengths equal to and greater than about 700 MPa. Ceramic powders comprised of nanoparticulate crystallites are used to manufacture dental articles. The ceramic powders may include sintering agents, binders and other similar additives to aid in the processing of the ceramic powder into a dental article. The ceramic powders may be processed into dental articles using various methods including, but not limited to, injection molding, gel-casting, slip casting, or electroforming, hand, cad/camming and other various rapid prototyping methods. The ceramic powder may be formed into a suspension, pellet, feedstock material or a pre-sintered blank prior to forming into the dental article.

Abstract: A process for forming a coating on a substrate, such as a turbine engine component, is provided. The process comprises the steps of: providing a first rare earth oxide stabilized zirconia composition; providing a second composition selected from the group consisting of a yttria stabilized zirconia composition, a ceria stabilized zirconia composition, alumina, a chromia-alumina composition, a gadolinia stabilized zirconia composition, and mixtures thereof; blending the first rare earth oxide stabilized zirconia composition with the second composition to form a blended powder; and depositing the blended powder onto the substrate. Articles having the coating formed from the above process are also described.

Abstract: A substrate for a heating assembly comprising a mixture of a mica material with an electrically insulating material, the substrate having a thermal coefficient of expansion that is higher than pure mica. A method of manufacturing the substrate is also disclosed.

Abstract: The invention concerns a sintered refractory product having the following average chemical composition, in weight percentages based on oxides: 20%<Al2O3<90%; 6%=SiO2<30%; 3%<ZrO2<50%; 0%=Cr2O3<50%. The inventive product is characterized in that it comprises 17 to 85 wt. % of mullite-zirconium grains.

Abstract: The present invention relates to a sintered product elaborated from a starting charge containing 75-99% of zircon, in mass percentage based on the oxides and having the following average weight chemical composition, in mass percentages based on the oxides 60%?ZrO2?72.8%, 27%?SiO2?36%, 0.1%?B2O3+GeO2+P2O5+Sb2O3+Nb2O5+Ta2O5+V2O5, 0.1%?ZnO+PbO+CdO, B2O3+GeO2+P2O5+Sb2O3+Nb2O5+Ta2O5+V2O5+ZnO+PbO+CdO?5% 0% ?Al2O3+TiO2+MgO+Fe2O3+NiO+MnO2+CoO+CuO?5%, other oxides: ?1.5%, for a total of 100%. Notably used in a glass furnace.

Abstract: Proposed is a zirconium crucible used for melting an analytical sample in the pretreatment of the analytical sample, wherein the purity of the zirconium crucible is 99.99 wt % or higher. In light of the recent analytical technology demanded of fast and accurate measurement of high purity materials, the present invention provides a zirconium crucible for melting an analytical sample, a method of preparing such analytical sample, and a method of analysis that enables the analysis of high purity materials by inhibiting the inclusion of impurities from the crucible regardless of difference in the analysts and their skill.

Abstract: A ZrO2—Al2O3 composite ceramic material having excellent wear resistance, hardness, strength and toughness is provided. This ceramic material comprises a ZrO2 phase composed of 90 vol % or more of tetragonal ZrO2, and containing 10 to 12 mol % of CeO2 as a stabilizer, and an Al2O3 phase. An amount of the Al2O3 phase in the ceramic material is in a range of 20 to 70 vol %, and preferably 40 to 70 vol %. In the composite ceramic material, Al2O3 grains each having a fine ZrO2 grain therein are dispersed. Some of the Al2O3 grains each having the fine ZrO2 grain therein are trapped within ZrO2 grains to form composite grains. A ratio of the number of the Al2O3 grains each having the fine ZrO2 grain therein relative to the number of the entire Al2O3 grains dispersed in the composite ceramic material is 10% or more, and preferably 50% or more.

Abstract: Wet-chemical methods involving the use of water-soluble hydrolytically stable metal-ion chelate precursors and the use of a nonmetal-ion-containing strong base can be used in a coprecipitation procedure for the preparation of ceramic powders. Examples of the precipitants used include tetraalkylammonium hydroxides. A composition-modified barium titanate is one of the ceramic powders that can be produced. Certain metal-ion chelates can be prepared from 2-hydroxypropanoic acid and ammonium hydroxide.

Abstract: A subject of the invention relates to providing a powder for a translucent zirconia sintered body which is necessary for the production of a zirconia sintered body having a high sintered-body density and high strength and giving an excellent sense of translucency, without conducting any special sintering, such as HIP sintering. The invention relates to a technique for obtaining, through normal-pressure sintering, a translucent zirconia sintered body characterized by comprising zirconia which contains 2-4 mol % yttria as a stabilizer and has an alumina content of 0.2 wt % or lower, and by having a relative density of 99.8% or higher and a total light transmittance, as measured at a thickness of 1.0 mm, of 35% or higher. It is preferred that a powder containing 0-0.2 wt % alumina with a particle diameter of 0.01-0.5 ?m, having a BET specific surface area of 5-16 m2/g and an average particle diameter of 0.3-0.7 ?m, and having a rate of sintering shrinkage in normal-pressure sintering (??/?T; g/cm3·° C.) of 0.

Abstract: This invention provides a colored zirconia-based sintered body, mainly composed of zirconia containing a stabilizer, which contains alumina and nickel spinel, and has a novel color tone, and a method for manufacturing such a zirconia-based sintered body. The colored zirconia-based sintered body is applicable not only to a highly decorative product such as a watch, but also to knives, tweezers, machining jigs and holding jigs for electronic parts, and sliding members.

Abstract: A ceramic article may comprise a sintered phase ceramic composition comprising aluminum titanate (Al2TiO5), zirconium titanate (ZrTiO4), and a niobium-doped phase.

Abstract: A high-zirconia cast refractory material which contains 85-95 wt % of ZrO2, 4-12 wt % of SiO2, 0.1 to less than 0.8 wt % of Al2O3, less than 0.04 wt % of Na2O, 0.01-0.15 wt % of K2O, 0.1-1.5 wt % of B2O3, 0.01-0.2 wt % of CaO, less than 0.4 wt % of BaO, less than 0.2 wt % of SrO, 0.05-0.4 wt % of Y2O3, and 0.3 wt % or less of Fe2O3 and TiO2 together, but does not substantially contain CuO and P2O5 (less than 0.01 wt %), such that the molar ratio of the glass-forming oxides (such as SiO2 and B2O3) to the glass-modifying oxides (such as Na2O, K2O, CaO, MgO, SrO, and BaO) is 20-100, said refractory material having an electric resistance being 200 ?·cm or higher after standing for 12 hours at 1500° C.

Abstract: In one aspect, the invention includes a refractory material for a pyrolysis reactor for pyrolyzing a hydrocarbon feedstock, the refractory material comprising an yttria stabilized zirconia, the refractory material comprising at least 21 wt. % yttria based upon the total weight of the refractory material. In another aspect, this invention includes a method for mitigating carbide corrosion while pyrolyzing a hydrocarbon feedstock at high temperature using a pyrolysis reactor system comprising the steps of: (a) providing a pyrolysis reactor system comprising stabilized zirconia in a heated region of the reactor, the stabilized zirconia including at least 21 wt. % yttria and having porosity of from 5 vol. % to 28 vol. %; (b) heating the heated region to a temperature of at least 1500° C.; and (c) pyrolyzing a hydrocarbon feedstock within the heated region.

Abstract: Method to produce an element (10) subject to wear, such as a mechanical member, an abrasion or crushing tool or suchlike, comprising a metal matrix (14) and at least a core (12) of ceramic material. The method comprises a preliminary step wherein the core (12) is prepared by mixing at least a first component with a base of aluminum oxide in the form of a (a-Al2O3) with a second component comprising a eutectic compound with a base of a-Al2O3 and ZrO2, a second step wherein the core (12) is arranged in a mold, so as to define a free volume inside the mold, and a third step wherein a molten metal material is cast into the mold, to occupy the free volume so as to anchor to the core (12) and thus form a single body.

Abstract: A biomedical member having high strength, high toughness and high hardness and an artificial joint that uses the same are provided. In addition, a biomedical member that exhibits high wear resistance even in in vivo environment and an artificial joint are provided. Such a composite ceramic is used that contains 65% by weight or more Al2O3, 4 to 34% by weight of ZrO2 and 0.1 to 4% by weight of SrO, while Sr forms a solid solution with part of the ZrO2 grains. The composite ceramics further contains TiO2, MgO and SiO2 as sintering additives, while controlling the amounts to 0.20% by weight or more SiO2, 0.22% by weight or more TiO2 and 0.12% by weight or more MgO, and the total amount of SiO2, TiO2 and MgO within a range from 0.6 to 4.5% by weight.

Abstract: The invention provides a novel fused cast refractory product with a high zirconia content having improved electrical resistivity. Said refractory product comprises, as a percentage by weight based on the oxides and for a total of more than 98.5%: ZrO2+Hf2O: >85%; SiO2: >10% to 12%; Al2O3: 0.1% to 2.4%; B2O3: <1.5%; and a dopant selected from the group formed by V2O5, CrO3, Nb2O5, MoO3, Ta2O5, WO3, and mixtures thereof, in a weighted quantity as expressed below: 2.43V2O5+4.42CrO3+1.66Nb2O5+3.07MoO3+Ta2O5+1.91WO3?0.2%.

Abstract: Dental articles are produced using relatively low sintering temperatures to achieve high density dental articles exhibiting strengths equal to and greater than about 700 MPa. Ceramic powders comprised of nanoparticulate crystallites are used to manufacture dental articles. The ceramic powders may include sintering agents, binders and other similar additives to aid in the processing of the ceramic powder into a dental article. The ceramic powders may be processed into dental articles using various methods including, but not limited to, injection molding, gel-casting, slip casting, or electroforming, hand, cad/camming and other various rapid prototyping methods. The ceramic powder may be formed into a suspension, pellet, feedstock material or a pre-sintered blank prior to forming into the dental article.

Abstract: This invention provides a colored zirconia-based sintered body, mainly composed of zirconia containing a stabilizer, which contains alumina and nickel spinel, and has a novel color tone, and a method for manufacturing such a zirconia-based sintered body. The colored zirconia-based sintered body is applicable not only to a highly decorative product such as a watch, but also to knives, tweezers, machining jigs and holding jigs for electronic parts, and sliding members.

Abstract: A spark plug which includes a center electrode metal shell and an insulator disposed therebetween utilizes for the insulator or ceramic with improved high temperature electrical properties which includes alumina in an amount between about 90 and about 99% by weight, a zirconium containing compound in an amount between about 0 and about 1% by weight, and an oxide mixture in an amount between about 1 and about 10% by weight. The oxide mixture includes a glass former, a network modifier and alumina in an amount between about 16% and about 40% by weight after firing, wherein the molar ratio of the glass former to the network modifier ranges between about 0.8:1 and 1.2:1. The ceramic insulator is particularly adapted for use as an insulator in a spark plug to provide improved dielectric strength and shunt resistance of greater than one 1000 megaohms at 1000 degrees Fahrenheit, so as to reduce the shunting of the spark plug and thereby improve the quality of the spark generated by the spark plug.

Abstract: Hardness, ageing resistance, wetting behavior in relating to water and high thermal conductivity are known characteristics of sintered molded bodies consisting of aluminum oxide; high strength and a high resistance to cracking, i.e., damage tolerance are known characteristics of sintered molded bodies consisting of zirconium oxide. These properties are combined in a material having a large fraction of aluminum oxide, zirconium oxide and optionally strontium aluminate.

Abstract: Methods of making and compositions of dense sintered ceramic nano- and micro-composite materials that are highly stable in a variety of conditions and exhibit superior toughness and strength. Liquid feed flame spray pyrolysis techniques form a plurality of nanoparticles (e.g., powder), each having a core region including a first metal oxide composition comprising Ce and/or Zr or other metals and a shell region including a second metal oxide composition comprising Al or other metals. In certain aspects, the core region comprises a partially stabilized tetragonal ZrO2 and the shell region comprises an ?-Al2O3 phase. The average actual density of the ceramic after sintering is greater than 50% and up to or exceeding 90% of a theoretical density of the ceramic.

Abstract: Disclosed are ceramic articles comprising a sintered phase ceramic composition containing, as expressed on a weight percent oxide basis: a(Al2TiO5)+b(ZrTiO4)+c(Y2O3)+d(YPO4) wherein “a, b, c, and d” represent weight fractions of each component such that (a+b+c+d)=1.00 and wherein 0.5<a?0.95; 0?b?0.5, 0.0?c?0.10, and 0?d?0.5. Also disclosed are precursor batch compositions and methods for manufacturing the ceramic articles disclosed herein.

Abstract: Aqueous dispersion containing a metal oxide powder with a fine fraction and a coarse fraction, in which—the metal oxide powder is silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, cerium oxide or a mixed oxide of two or more of the aforementioned metal oxides,—the fine fraction is present in aggregated form and has a mean aggregate diameter in the dispersion of less than 200 nm,—the coarse fraction consists of particles with a mean diameter of 1 to 20 ?m, —the ratio of fine fraction to coarse fraction is 2:98 to 30:70, and—the content of metal oxide powder is 50 to 85 wt. %, referred to the total amount of the dispersion. The aqueous dispersion is produced by a process comprising the steps:—production of a fine fraction dispersion by dispersing the pulverulent fine fraction in water by means of an energy input of at least 200 KJ/m3?, and—introducing the coarse fraction in the form of a powder into the fine fraction dispersion under dispersing conditions at a low energy input.

Abstract: Sintered product produced from a starting charge containing 75 to 99% zircon, and having the following average chemical composition by weight, the percentages by weight being based on the oxides: 60%<ZrO2+HfO2<75%; 27%<SiO2<34%; O<TiO2; O<Y2O3<3.5%; 0.1%<Nb2O5+Ta2O5<=5%; and other oxides: <1.5%; for a total of 100%, The sintered product may be used in a glass furnace.

Abstract: A ceramic article which is resistant to erosion by halogen-containing plasmas used in semiconductor processing. The ceramic article includes ceramic which is multi-phased, typically including two phase to three phases. The ceramic is formed from yttrium oxide at a molar concentration ranging from about 50 mole % to about 75 mole %; zirconium oxide at a molar concentration ranging from about 10 mole % to about 30 mole %; and at least one other component, selected from the group consisting of aluminum oxide, hafnium oxide, scandium oxide, neodymium oxide, niobium oxide, samarium oxide, ytterbium oxide, erbium oxide, cerium oxide, and combinations thereof, at a molar concentration ranging from about 10 mole % to about 30 mole %.

Abstract: This invention relates to ceramic powders comprising a zirconia-based component, e.g., yttria-stabilized zirconia, and an (alumina+silica)-based component, e.g., mullite. The ceramic powders are useful for forming thermal shock resistant coatings having the same composition, through deposition by thermal spray devices. This invention also relates to thermal barrier coating systems suitable for protecting components exposed to high temperature environments, such as the thermal environment of a gas turbine engine. This invention further relates to forming free-standing solid ceramic articles.

Abstract: A novel fused and cast refractory product with a high zirconia content having improved electrical resistivity includes, as a percentage by weight relative to the oxides and for a total of more than 98.5%: ZrO2 + Hf2O: >85% SiO2: 2% to 10% Al2O3: 0.1% to 2.4%, with Al2O3/SiO2 <0.5 Y2O3: ?1%, B2O3: <1.5%; and a dopant selected from the group formed by V2O5, CrO3, Nb2O5, MoO3, Ta2O5, WO3, and mixtures thereof, in a weighted quantity such that: 0.2%?2.43V2O5+8.84CrO3+1.66Nb2O5+6.14MoO3+Ta2O5+3.81WO3.

Abstract: The present invention provides a fused cast refractory block comprising a mean zirconia (ZrO2+HfO2) content of more than 85% as a percentage by weight based on the oxides, and with a standard deviation ? of the local zirconia content divided by the volume of the block of less than 7.5.

Abstract: A translucent zirconia sintered body, a dental article comprising a shaped, translucent zirconia body, a zirconia green body, and methods of making a translucent zirconia sintered body, methods of making a dental article comprising a shaped, translucent zirconia body, and methods of making a zirconia green body are described.

Abstract: The invention provides a novel fused and cast refractory product with a high zirconia content having improved electrical resistivity. Said refractory product comprises, as a percentage by weight relative to the oxides and for a total of more than 98.5%: ZrO2+Hf2O: >85% SiO2: 1% to 12% Al2O3: 0.1% to 2.4%, with Al2O3/SiO2<0.5 Y2O3: ?1%, B2O3: <1.5%; and a dopant selected from the group formed by V2O5, CrO3, Nb2O5, MoO3, Ta2O5, WO3, and mixtures thereof, in a weighted quantity such that: 0.2%?2.43V2O5+8.84CrO3+1.66Nb2O5+6.14MoO3+Ta2O5+3.81WO3.

Abstract: Part of the surface of a metallic-oxide refractory ceramic part, such as a fusion-cast refractory block, is treated using a high energy beam, to remove portions of the surface. A metal film may then be sprayed onto the treated surface of the ceramic part, for example to provide protection against erosion/corrosion in glass furnaces. Excellent adhesion between metal and ceramic can be attained.

Abstract: A zirconia porous body with excellent stability of heat resistance is manufactured. This relates to a zirconia porous body having peaks at pore diameters of 8 to 20 nm and 30 to 100 nm in a pore distribution based on the BJH method, with a total pore volume of 0.4 cc/g or more, and to a zirconia porous body having a peak at a pore diameters of 20 to 110 nm in a pore distribution based on the BJH method, with a total pore volume of 0.4 cc/g or more.

Abstract: An AZS type fused cast refractory product presenting the following chemical composition, as a percentage by weight: ZrO2: 15.5% to 22%; SiO2: 10.5% to 15%; Na2O+K2O+Li2O: 1.0% to 2.5%; impurities: <1%. Application to glass furnaces, in particular to the superstructures and crowns thereof.

Abstract: A composite ceramic body with increased strength is disclosed. The composite ceramic body, composed of a matrix of alumina particles with a mean particle diameter ranging from 0.7 to 1.8 ?m and nano-zirconia particles with a particle diameter of 0.15 ?m or less, wherein the alumina particles and the nano-zirconia particles fall in a respective weight percentage ratio ranging from 80:20 to 95:5 with a relative density of 93% or more and wherein in a cross section, a total sum of surface areas of pores, having cross-sectional areas equal to or greater than surface areas of circles having the same diameters as a mean particle diameter of the alumina particles, falls in a value of 2.2% or less based on a whole of the cross-sectional areas.

Abstract: A material comprising: from 98-50% by volume of zirconia as a matrix, which is stabilized with i) either of from about 2 to about 3 mole percent of yttria ii) or of from about 10 to about 15 mole percent of ceria; iii) or a mixture of ceria and yttria in the range of amounts as given in i) and ii) the stabilizing oxides may be substituted against each other in a ratio from 1:99 to 99:1 and a maximum stabilization of 3 mole percent related to pure yttria and 15 mole percent related to pure ceria respectively are not exceeded, and wherein the term mole percent is related to the zirconia matrix and wherein the zirconia matrix is obtainable from a) a powder of particles of zirconia having a mean particle size of <0.

Abstract: A zirconia porous body with excellent stability of heat resistance is manufactured. This relates to a zirconia porous body having peaks at pore diameters of 8 to 20 nm and 30 to 100 nm in a pore distribution based on the BJH method, with a total pore volume of 0.4 cc/g or more, and to a zirconia porous body having a peak at a pore diameters of 20 to 110 nm in a pore distribution based on the BJH method, with a total pore volume of 0.4 cc/g or more.

Abstract: A sintered ceramic material comprising: a) from 98-50% by volume of zirconia as a matrix, i) stabilized with a stabilizing composition having ii) of from about 2 to about 3 mole percent of yttria and of from about 10 to about 15 mole percent of ceria; wherein the term mole percent is related to the zirconia matrix and iii) the stabilizing composition is present in the range of from about 1:99 to about 99:1; and b) from about 2 to about 50% by volume of alumina of which from about 5 to about 90% by volume is in the form of hexagonal platelets of general formula REAl 11018, where RE stands for rare earth metal.

Abstract: A fusion-cast refractory is provided. The refractory comprises 0.8% to 2.5% Al2O3, 4.0% to 10.0% SiO2, 86% to 95% ZrO2, 0.1% to 1.2% B2O3, up to 0.04% Na2O, up to 0.4% CaO, up to 0.1% Fe2O3 and up to 0.25% TiO2.

Abstract: A ZrO2—Al2O3 composite ceramic material having excellent wear resistance, hardness, strength and toughness is provided. This ceramic material comprises a ZrO2 phase composed of 90 vol % or more of tetragonal ZrO2, and containing 10 to 12 mol % of CeO2 as a stabilizer, and an Al2O3 phase. An amount of the Al2O3 phase in the ceramic material is in a range of 20 to 70 vol %, and preferably 40 to 70 vol %. In the composite ceramic material, Al2O3 grains each having a fine ZrO2 grain therein are dispersed. Some of the Al2O3 grains each having the fine ZrO2 grain therein are trapped within ZrO2 grains to form composite grains. A ratio of the number of the Al2O3 grains each having the fine ZrO2 grain therein relative to the number of the entire Al2O3 grains dispersed in the composite ceramic material is 10% or more, and preferably 50% or more.

Abstract: Novel, monodispersed, spherical ZrO2 particles in the size range of approximately 10 to approximately 600 nm exhibiting metastable tetragonal crystal structure at room temperature and novel methods of preparation. The ZrO2 particles are approximately 100% in the tetragonal phase at room temperature and can be pure and free of foreign oxides. The novel method can include mixing zirconium-alkoxide and an alcohol, forming preparation one, followed by separately dissolving completely de-ionized water and a polymeric steric stabilizer in an alcohol forming preparation two. Next the preparations can be mixed with vigorous stirring while subjecting the materials to hydrolysis and condensation reactions with very slow stirring. Next, there is waiting for the formation of a sol from the mixture, followed by drying at approximately 80 degrees C. to form resultant material followed by crushing the resultant material.

Abstract: The invention concerns a sintered refractory product having the following average chemical composition, in weight percentages based on oxides: 20%<Al2O3<90%; 6%=SiO2<30%; 3%<ZrO2<50%; 0%=Cr2O3<50%. The inventive product is characterized in that it comprises 17 to 85 wt. % of mullite-zirconium grains.

Abstract: In dental ceramics containing zirconium dioxide and silicon-dioxide with a Zr/Si ratio of between 0.5 and 1.0, 1 to 12 wt % of aluminum oxide and up to 2 wt % of an alkali- or earth alkali metal oxide, those materials are selectively mixed with yttrium-stabilized zirconium dioxide with a Zr/Si ratio of the mixture being between 0.5 and 1 wt % and also a silicon organic compound as well as a compression aid, and a green body is formed from the mixture by milling, which green body is then sintered.

Abstract: A zirconia-containing powder including 2 to 6 weight % of a pigment which has a spinel structure represented by the chemical formula (Co1-xZnx)(Fe1-yAly)2O4(0?x?0.5, 0<y?0.5) or which is a coprecipitated material containing Co, Zn, Fe, and Al and has the same spinel structure after calcination, 0.05 to 6 weight % of Al2O3, and 3.60 to 7.10 weight % of Y2O3; and a black zirconia sintered body obtained by sintering the zirconia-containing powder within a temperature range of 1300 to 1500° C.

Abstract: The invention is directed to a material and a method of substantially eliminating destructive low-temperature, humidity-enhanced phase transformation of yttria-stabilized zirconia in general, as well as eliminating low-temperature degradation of yttria-stabilized tetragonal zirconia polycrystalline ceramic (Y-TZP). The martensitic-type phase transformation from tetragonal to monoclinic is accompanied by severe strength degradation in a moist environment at low-temperature, specifically at room temperature as well as at body temperature. This class of materials has been chosen as the packaging material for small implantable neural-muscular sensors and stimulators because of the high fracture toughness and high mechanical strength. This destructive phase transformation has been substantially eliminated, thus ensuring the safety of long-term implants, by subjecting the sintered components to post-machining hot isostatic pressing, such that the average grain size is less than about 0.5 microns.

Abstract: The invention relates to a hollow piece for producing a sintered refractory having the following mean mineral chemical composition in weight percent based of mineral oxides: 40%=Al2O3=94%, 0%=ZrO2=41%, 2%=SiO2=22%, 1%<Y2O3+V2O5+TiO2+Sb2O3+Yb2O3+Na2O.

Abstract: To make a color tone similar to that of dentin of a tooth at a low cost without discoloration when baking, a dental ceramics material is produced by: mixing a pink coloring agent and a yellow coloring agent with zirconium oxide containing a stabilizer while having a mixing ratio of 0.001 to 5 wt. % respectively; and baking it, where the pink coloring agent is obtained by dissolving manganese oxide in aluminum oxide as a solid solution, the yellow coloring agent is obtained by dissolving vanadium oxide in zirconium oxide as a solid solution, the zirconium oxide contains 0.1 to 30 wt. % aluminum oxide if necessary, the stabilizer is one or more kinds selected from a group including yttrium oxide, magnesium oxide, calcium oxide, and cerium oxide, and the content thereof is preferably 3 to 7 wt. %.

Abstract: A novel fused and cast refractory product with a high zirconia content having improved electrical resistivity includes, as a percentage by weight relative to the oxides and for a total of more than 98.5%: ZrO2+Hf2O: >85% SiO2: 2% to 10% Al2O3: 0.1% to 2.4%, with Al2O3/SiO2<0.5 Y2O3: ?1%, B2O3: <1.5%; and a dopant selected from the group formed by V2O5, CrO3, Nb2O5, MoO3, Ta2O5, WO3, and mixtures thereof, in a weighted quantity such that: 0.2%?2.43V2O5+8.84CrO3+1.66Nb2O5+6.14MoO3+Ta2O5+3.81WO3.

Abstract: A ceramic consisting essentially of: about 51% to about 68% by weight ZrO2; about 20% to about 40% by weight Al2O3; about 9% to about 12% by weight CeO2; about 0.05% to about 0.2% by weight SiO2; about 0.01% to about 0.1% by weight MgO; about 0.1% to about 0.6% by weight MnO; and about 0.01% to about 0.8% by weight CaO.