Abstract: The invention relates to a vapor-deposition material for the production of optical layers of medium refractive index which comprises aluminum oxide and gadolinium oxide, dysprosium oxide and/or ytterbium oxide, to a process for the preparation thereof, and to the use thereof.

Abstract: A nickel oxide co-doped with a first alkali metal dopant and a second metal dopant selected from the group consisting of at least one of tin, antimony, indium, tungsten, iridium, scandium, gallium, vanadium, chromium, gold, yttrium, lanthanum, ruthenium, rhodium, molybdenum, and niobium.

Abstract: There is provided a strengthened composite material that is able to improve yield, handling, and reliability when it is applied to members of semiconductor manufacturing apparatus. Five to 60 mol % ZrO2 is contained relative to Y2O3, and temperature after a sintering process is maintained between 1,200° C. to 1,500° C. for 5 minutes or longer or temperature falling speed to reach 1,200° C. is adjusted to 200° C./h or slower, thereby producing the composite material containing, as major crystalline phases, a Y2O3 solid solution in which ZrO2 is dissolved in Y2O3 and a ZrO2 solid solution in which Y2O3 is dissolved in ZrO2.

Abstract: The transparent polycrystalline optoceramic has single grains with a symmetric cubic crystal structure and at least one optically active center. The optoceramic has the following formula: A2+xByDzE7, wherein 0?x?1.1, 0?y?3, 0?z?1.6, and 3x+4y+5z=8, and wherein A is at least one trivalent rare earth cation, B is at least one tetravalent cation, D is at least one pentavalent cation, and E is at least one divalent anion. The method of making the optoceramic includes preparing a powder mixture from starting materials, pre-sintering, sintering and then compressing to form the optoceramic. Scintillator media made from the optoceramic are also described.

Abstract: The transparent polycrystalline optoceramic has single grains with a symmetric cubic crystal structure and at least one optically active center. The optoceramic has the following formula: A2+xByDzE7, wherein ?1.15?x?0, 0?y?3, 0?z?1.6, and 3x+4y+5z=8, and wherein A is at least one trivalent rare earth cation, B is at least one tetravalent cation, D is at least one pentavalent cation, and E is at least one divalent anion. The method of making the optoceramic includes preparing a powder mixture from starting materials, pre-sintering, sintering and then compressing to form the optoceramic. Scintillator media made from the optoceramic are also described.

Abstract: Disclosed are a concentrate of fine ceria particles for chemical mechanical polishing, and a method of preparing the same. The method includes reacting a reactant mixture comprising i) water, ii) an aqueous solution of water-soluble cerium salt compound, and iii) ammonia or ammonium salt at a reaction temperature of 250-700? under a reaction pressure of 180-550 bar for 0.01 sec to 10 min in a continuous reactor to obtain a solution containing the fine ceria particles, the cerium salt compound being contained at an amount of 0.01 to 20 wt % in the reactant mixture; and concentrating the solution containing the fine ceria particles in a concentrator having a filter with a pore size of 0.01 to 10?. The concentrate is advantageous in that a CMP slurry and a dispersing solution are easily produced by diluting the concentrate and adding an additive to the concentrate.

Abstract: Methods of forming aluminum oxynitride (AlON) materials include sintering green bodies comprising aluminum orthophosphate or another sacrificial material therein. Such green bodies may comprise aluminum, oxygen, and nitrogen in addition to the aluminum orthophosphate. For example, the green bodies may include a mixture of aluminum oxide, aluminum nitride, and aluminum orthophosphate or another sacrificial material. Additional methods of forming aluminum oxynitride (AlON) materials include sintering a green body including a sacrificial material therein, using the sacrificial material to form pores in the green body during sintering, and infiltrating the pores formed in the green body with a liquid infiltrant during sintering. Bodies are formed using such methods.

Abstract: The refractive, transmissive or diffractive optical elements are made from a ceramic containing one or more oxides of the type X2O3, which is transmissive for visible light and/or for infrared radiation and which has a cubic crystal structure analogous to that of Y2O3. In preferred embodiments X is Y, Sc, In, or a lanthanide element, namely La to Lu, and in particular is Lu, Yb, Gd, or La. Also mixtures of oxides of the type X2O3 with oxides having different stoichiometries, such as HfO2 and/or ZrO2, may be present, as long as the cubic structure of the ceramic is maintained.

Abstract: A hot axial pressing method for sintering a ceramic powder, particularly doped Gd2O2S, comprise the step of placing a first porous body (7), the ceramic powder (9) and a second porous body (7) into a mould shell (5) supported by a support (13, 14). The ceramic powder (9) is located between the porous bodies (7). Gaseous components are evacuated from the ceramic powder (9) up to an ambient pressure of less than 0.8 bar. The porous body (7) and the ceramic powder (9) are heated to a maximum temperature of at least 900° C. and are applied to a pressure up to a maximum pressure of at least 75 Mpa. According to the invention the variation in time of the heating step and the variation in time of the pressure applying step is adjusted to each other such that the mould shell 5 is held by the porous bodies (7) and/or the ceramic powder (9) in a state where the mould shell (5) and the support (13, 14) are disconnected with respect to each other.

Abstract: A high purity nano-sized Yb3+ doped Y2O3 (Yb:Y2O3) ceramic powder with a narrow size distribution and without hard agglomerates is provided. Also provided is a process for manufacturing the same wherein water in the reaction bath is replaced by a non-water washing agent having little or no hydrogen bonding capability to inhibit the formation of hard agglomerates in the ceramic powder.

Abstract: A transparent polycrystalline ceramic having scattering and absorption loss less than 0.2/cm over a region comprising more than 95% of the originally densified shape and further provides a process for fabricating the same by hot pressing. The ceramic can be any suitable ceramic such as yttria (Y2O3) or scandia (Sc2O3) and can have a doping level of from 0 to 20% and a grain size of greater than 30 ?m, although the grains can also be smaller than 30 ?m. In a process for making a transparent polycrystalline ceramic in accordance with the present invention, ceramic nanoparticles can be coated with a sintering aid to minimize direct contact of adjacent ceramic powder particles and then baked at high temperatures to remove impurities from the coated particles. The thus-coated particles can then be densified by hot pressing into the final ceramic product. The invention further provides a transparent polycrystalline ceramic solid-state laser material and a laser using the hot pressed polycrystalline ceramic.

Abstract: A hydrothermal process for making Alpha Alumina (?-Al2O3) crystalline nano-sized powders in the form of at least one of nano-sheets and nano-fibers, the process includes making the Alpha Alumina with an aspect ratio of diameter to thickness ratio of at least two, and with at least one dimension of diameter or thickness being less than 100 nm. A composition in accordance with the process. A porous ceramic that includes the composition.

Abstract: Ceramic materials with relatively high resistance to wetting by various liquids, such as water, are presented, along with articles made with these materials. The oxide materials described herein as a class typically contain one or more of ytterbia (Yb2O3) and europia (Eu2O3). The oxides may further contain other additives, such as oxides of gadolinium (Gd), samarium (Sm), dysprosium (Dy), or terbium (Tb). In certain embodiments the oxide, in addition to the ytterbia and/or europia, further comprises lanthanum (La), praseodymium (Pr), or neodymium (Nd).

Abstract: Ceramic materials with relatively high resistance to wetting by various liquids, such as water, are presented, along with articles made with these materials. The oxide materials described herein as a class typically contain one or more of ytterbia (Yb2O3) and europia (Eu2O3). The oxides may further contain other additives, such as oxides of gadolinium (Gd), samarium (Sm), dysprosium (Dy), or terbium (Tb). In certain embodiments the oxide, in addition to the ytterbia and/or europia, further comprises lanthanum (La), praseodymium (Pr), or neodymium (Nd).

Abstract: Inorganic microporous metal oxide materials, such as aluminum-based microporous ceramic materials, useful for loop heat pipes, insulators, thermal management devices, catalyst supports, substrates, and filters, among others. An example method of manufacture includes heating a mixture of alumina (Al2O3) and aluminum carbonate (Al2(CO3)3) powders to a temperature of at least about 1400 degrees Celsius for a pre-selected time.

Abstract: According to one embodiment, a method for forming a composite transparent ceramic preform includes forming a first suspension of oxide particles in a first solvent which includes a first dispersant but does not include a gelling agent, adding the first suspension to a first mold of a desired shape, and uniformly curing the first suspension in the first mold until stable. The method also includes forming a second suspension of oxide particles in a second solvent which includes a second dispersant but does not include a gelling agent, adding the second suspension to the stable first suspension in a second mold of a desired shape encompassing the first suspension and the second suspension, and uniformly curing the second suspension in the second mold until stable. Other methods for forming a composite transparent ceramic preform are also described according to several other embodiments. Structures are also disclosed.

Abstract: A semiconductor porcelain composition [(BiNa)x(Ba1-yRy)1-x]TiO3 with 0<x?0.2, 0<y?0.02 and R being selected from the group consisting of La, Dy, Eu, Gd or Y is prepared by separately calcining a composition of (BaR)TiO3 at a temperature of 900° C. through 1300° C. and calcining a composition of (BiNa)TiO3 at a temperature of 700° C. through 950° C., and then mixing the two calcined powders and forming and sintering the mixed calcined powder. Similarly, a semiconductor porcelain composition [(BiNa)x(Ba1-x][Ti1-zMz]O3 with 0<x?0.2, 0<z?0.005 and M being selected from the group consisting of Nb, Ta and Sb is prepared by separately calcining a composition of (BaM)TiO3 at a temperature of 900° C. through 1300° C. and calcining a composition of (BiNa)TiO3 at a temperature of 700° C. through 950° C., and then mixing the two calcined powders, and forming and sintering the mixed calcined powders.

Abstract: A composition for thermal barrier coatings exhibiting improved thermal conductivity and toughness is provided. The composition is comprised of a base majority oxide, a first dopant oxide, at least one small rare earth oxide, at least one large rare earth oxide and at least one toughening oxide. Compared to traditional thermal barrier coatings, a composition of the present invention provides approximately twice the toughness one-third to one-half the thermal conductivity.

Abstract: The opto-ceramics and optical elements of the present invention are transmissive to visible light and/or to infrared radiation. They consist of a crystal combination in which individual crystallites have a cubic structure of the type Y2O3 and are made from In2O3 or a mixture of oxides of the type X2O3 in which X=Y, Lu, Sc, Yb, In, Gd, or La. Also mixtures of X2O3 with oxides having different stoichiometries, such as zirconium and hafnium oxide, are possible, as long as the cubic structure of the opto-ceramic is maintained. The optical elements prepared from the opto-ceramics are particularly suitable for mapping optics, such as objectives having reduced chromatic aberrations, in particular with approximately apochromatic mapping behavior. The optical elements of the present invention may be used in lens systems in combination with lenses of glass, but also with other ceramic lenses.

Abstract: A thermal spray powder contains granulated and sintered yttria particles and fine yttria particles, the average particle diameter of the fine yttria particles being no more than 1 ?m. The content of the fine yttria particles in the thermal spray powder is 1,000 to 10,000 ppm by mass. It is preferred that the thermal spray powder be used in applications for forming a thermal spray coating by plasma thermal spraying at atmospheric pressure.

Abstract: A method of producing a semiconductor disk represented by a composition formula [(Bi0.5Na0.5)x(Ba1?yRy)1?x]TiO3, in which R is at least one element of La, Dy, Eu, Gd and Y and x and y each satisfy 0?x?0.14, and 0.002?y?0.02 includes carrying out a sintering in an inert gas atmosphere with an oxygen concentration of 9 ppm to 1% and wherein a treatment at an elevated temperature in an oxidizing atmosphere after the sintering is not carried out.

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: Tunable variable emissivity materials, methods for fabricating tunable variable emissivity materials, and methods for controlling the temperature of a spacecraft using tunable variable emissivity materials have been provided. In an exemplary embodiment, a variable emissivity material has the formula M1(1?(x+y))M2xM3yMnO3, wherein M1 comprises lanthanum, praseodymium, scandium, yttrium, neodymium or samarium, M2 comprises an alkali earth metal, M3 comprises an alkali earth metal that is not M2, and x, y, and (x+y) are less than 1. The material has a critical temperature (Tc) in the range of about 270 to about 320K and a transition width is less than about 30K.

Abstract: After synthesizing particles by liquid phase synthesis, the solution is substituted without drying these particles, and here, a solution comprising a grain boundary phase composition consisting of at least one or more types selected from a group consisting of Al2O3, yttrium oxide, silicon oxide, yttrium-silicon complex oxide, aluminum-silicon complex oxide, and a compound having a garnet structure with a lower melting point than the aforementioned particles, or a solution comprising a precipitate is introduced. Microparticles are adjusted by allowing adhesion and growth of the solution comprising a composition of grain boundary phase or the solution comprising a precipitate on the surface of the particles; these microparticles are allowed to align in 3-dimensions in solution and are formed into a molded body, and this molded body is sintered.

Abstract: Provided is a translucent ceramic which has a high Abbe number, is advantageous in aberration correction, and can be easily produced. The translucent ceramic contains, as a main component, a garnet type compound represented by the General Formula: Y3AlvOw, wherein the condition of 4.4?v?5.4 is satisfied and w is a positive number for maintaining electrical neutrality, in which the Al is partially or entirely substituted by Ga and the Y is optionally partly substituted by Gd. The translucent ceramic is suitably used, for example, for lenses arranged with a diaphragm interposed therebetween in a Gauss lens optical system, such as an optical system for single-lens reflex cameras.

Abstract: Provided is an optical element, which is formed by vacuum-sintering a molded body of ceramic particles having an average particle diameter of 1 ?m or more and 10 ?m or less and including LnxAlyO[x+y]×1.5 (Ln represents a rare-earth element, x represents 1?x?10, and y represents 1?y?5). Ln preferably includes at least one kind selected from La, Gd, Yb, and Lu. The optical element preferably has a refractive index of 1.85 or more and 2.06 ?m or less, and an Abbe number of 48 or more and 65 or less. The optical element having optical properties of high refractive index and low dispersibility is obtained.

Abstract: The invention relates to a vapour-deposition material for the production of optical layers of high refractive index which comprises titanium oxide and ytterbium oxide in a molar ratio of from 4:1 to 1:4, to a process for the preparation thereof, and to the use thereof.

Abstract: A method of forming (and an apparatus for forming) a metal-doped aluminum oxide layer on a substrate, particularly a semiconductor substrate or substrate assembly, using a vapor deposition process.

Abstract: An oxide/oxide CMC matrix comprising a rare earth phosphate bonding agent incorporated in the matrix, an insulating layer on the matrix, or both.

Abstract: A metal halide lamp according to the present invention includes: a main tube (6) made of a light-transmitting ceramic and forming a part of an arc tube; a first thin tube (7a) coupled to a first end of the main tube (6); a second thin tube (7b) coupled to a second end of the main tube (6); a pair of electrodes (5a, 5b), which are inserted into the first and second thin tubes (7a, 7b), respectively, such that the far ends thereof face each other inside the main tube (1); and a first metal halide enclosed in the arc tube. A second metal halide, which has a lower vapor pressure than that of the first metal halide, is further enclosed in the arc tube. And the main tube (6) has portions, of which the inside diameter decreases monotonically toward the ends.

Abstract: A ceramic material with a negative temperature coefficient of specific resistance has the general formula: [{(SE1III,SE2III)1?x(M1II,M2II)x}(Cr1?y?zMny(Me1III,Me2III)z)O3] wherein SE1III and SE2III are different rare-earth metal cations, M1II and M2II are selected from CaII, SrII, and Me1III and Me2III are redox-stable, trivalent metal cations, wherein the following applies with respect to the parameters: 0<x<1; 0<z<1; 0<y<1?z.

Abstract: A rare-earth oxide sintered body, or corrosion-resistant material, having low sintering temperature and high density is prepared by adding a boron compound at a ratio of 0.06 mol % or more and less than 25 mol % when converted into boron oxide (B2O3) to oxide powder of at least one of La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Sc, after which the mixed powder is formed and sintered. The sintered body comprises at least one of La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3, and Sc2O3, and at least one of Ln3BO6 (Ln=La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu), and Sc3BO6 as a main constituent crystal thereof.

Abstract: Disclosed herein is a material for altering electromagnetic radiation incident on the material. The material disclosed herein comprises carbon nanotubes having a length (L) that meets the following formula (1): L?½ ???(1) where ? is the wavelength of the electromagnetic radiation incident on the material. Also disclosed herein are methods of altering electromagnetic radiation, including mitigating, intensifying, or absorbing and re-transmitting electromagnetic radiation using the disclosed material.

Abstract: A tungsten bronze structured ceramic material as a thermal barrier coating is described wherein the tungsten bronze structured ceramic coating material has the formula AO—BvOw—CyOz where O stands for Oxygen, A stands for a 2+ or a 1+ cation, B stands for a 2+ or 3+ cation and C stands for a 4+ or a 5+ cation. The thermal barrier coating may be applied for gas turbine components.

Abstract: A transparent yttrium aluminum garnet precursor composition is provided that includes a plurality of calcined particles of yttrium aluminum oxide having a mean particle domain size of between 10 and 200 nanometers and a predominant hexagonal crystal structure. High levels of YAG transparency are obtained for large YAG articles through control of the aluminum:yttrium atomic ratio to 1:06±0.001 and limiting impurity loadings to less than 100 ppm. The composition is calcined at a temperature between 700° Celsius and 900° Celsius to remove organic additives to yield a predominant metastable hexagonal phase yttrium aluminum oxide nanoparticulate having an atomic ratio of aluminum: yttrium of 1:0.6±0.001. With dispersion in an organic binder and a translucent YAG article is formed having a transmittance at a wavelength of 1064 nanometers of greater than 75%.

Abstract: The present invention provides a fused product comprising LTM perovskite, L designating lanthanum, T being an element selected from strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium, and mixtures of these elements, and X designating manganese.

Abstract: Ceramic materials with relatively high resistance to wetting by various liquids, such as water, are presented, along with articles made with these materials, methods for making these articles and materials, and methods for protecting articles using coatings made from these materials. One embodiment is an article comprising a material that is transparent to electromagnetic radiation of at least one type selected from the group consisting of ultraviolet radiation, visible light, and infrared radiation. The material comprises a primary oxide and a secondary oxide. The primary oxide comprises cerium and hafnium. The secondary oxide comprises a secondary oxide cation selected from the group consisting of the rare earth elements, yttrium, and scandium. Another embodiment is an article comprising a material that is transparent to electromagnetic radiation of at least one type selected from the group consisting of ultraviolet radiation, visible light, and infrared radiation.

Abstract: A corrosion-resistant member having a high acid resistance, plasma resistance, and hydrophilicity and a process for producing the corrosion-resistant member are provided. The corrosion-resistant member is obtained by surface-treating an untreated member (a ceramic, a metal) to a surface-treatment with a spray of a superheated water vapor having a temperature of 300 to 1000° C. The corrosion-resistant member may be a member contacting with a processing space in a vapor phase surface process apparatus (e.g., a chamber) for the surface process of a substrate by a vapor phase method such as a PVD, a CVD, or a dry etching.

Abstract: Improving the resistance of members and parts disposed inside of vessels such as semiconductor processing devices for conducting plasma etching treatment in a strong corrosive environment. A ceramic coating member for a semiconductor processing apparatus comprises a porous layer made of an oxide of an element in Group IIIb of the Periodic Table coated directed or through an undercoat on the surface of the substrate of a metal or non-metal and a secondary recrystallized layer of the oxide formed on the porous layer through an irradiation treatment of a high energy such as electron beam and laser beam.

Abstract: A particulate subcomponent for a barium titanate dielectric is obtained from a sol in which a rare earth metal compound is dispersed in water. The rare earth metal compound includes a carboxylic acid having at least three carbonyl groups and at least one rare earth metal which can be Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu so that the molar ratio (carbonyl group/rare earth metal) is in the range of 1.2 to 3. A method of making the sol and a method of using the sol to make a ceramic powder is described.

Abstract: A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

Abstract: Methods for producing substantially single phase yttrium phosphate which exhibits the xenotime crystal structure are disclosed. The methods can be practiced without the use of high temperatures (e.g., the methods can be practiced at temperatures less than 1000° C.). The resulting yttrium phosphate can be in the form of particles which comprise interwoven strands of crystals of yttrium phosphate and/or nanoparticles prepared from such particles.

Abstract: The present invention relates to dielectric ceramics, thin and/or thick layers produced therefrom and a method for the production thereof and the use of the dielectrics and of the thin and/or thick layers.

Abstract: The invention relates to alkaline-earth or rare-earth metal aluminate precursor compounds, to their method of preparation and to their use in particular as phosphor precursors. These alkaline-earth or rare-earth metal aluminate precursor compounds are essentially crystallized in the form of a transition alumina and in the form of substantially spherical and chemically homogeneous particles including pores whose mean diameter is of at least 10 nm.

Abstract: A material which conducts protons or oxide ions with high ionic conductivity and is excellent in moisture resistance and reduction resistance is provided. A perovskite oxide represented by the formula (1): BaZraCebM1cL1dO3-???(1) (wherein M1 is at least one member selected from the group consisting of rare earth elements, In, Mn, Fe, Co, Ni, Al and Ga, L1 is at least one member selected from the group consisting of P, B and N and a, b, c, d and a satisfy 0?a<1.2, 0<b<1.2, 0<c<1.2, 0.9<a+b+c<1.2, 0<d<0.1 and 0<?<3) is used as an ionic conductor.

Abstract: A heat-insulating material has a first phase with the stoichiometric composition of 0.1 to 10 mol-% M12O3, 0.1 to 10 mol-% Li2O, and as the remainder M22O3 with possible impurities. M1 is selected from the elements lanthanum, neodymium, gadolinium, or a mixture thereof, and M2 is selected from the elements aluminum, gallium, iron, or a mixture thereof. The first phase is present in a magnetoplumbite structure.

Abstract: This invention discloses a kind of cerium-based oxide fiber and its fabricating method. The cerium-based hydrate fiber can be synthesized by aging under the boiling point of water for 10 hours to 50 hours by the addition of a chemical modifier. The fibers show a diameter of submicron to micron size, and the aspect ratio is greater than 100. The hydrate fibers can transform to oxide fiber after calcination at high temperature.

Abstract: The invention intends to obtain a transparent yttrium oxide sintered body of which in-line transmittance in a visible wavelength region of 400 to 800 nm at a thickness of 1 mm is 60% or more, without using aluminum that readily segregates in grain boundaries of yttrium oxide, without using special raw materials in which a silicon content is particularly reduced and without finely pulverizing raw materials. A transparent yttrium oxide sintered body that contains, with yttrium oxide as a main component, at least either one of tantalum or niobium or both thereof and has the in-line transmittance of 60% or more at a thickness of 1 mm in a visible wavelength region in the range of 400 to 800 nm.

Abstract: The present invention provides a lutetium oxide sinter to which yttrium is added in an amount of 100 mass ppm to 7000 mass ppm, whose average particle size is from 0.7 to 20 ?m, and with which there is no precipitation of a hetero phase containing yttrium at the grain boundary.

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.