There is provided a raw material for a zirconia sintered body formed by pressureless sintering and having a high fracture toughness value measured by an SEPB method, a sintered body formed from the raw material, and a method for producing at least one of the raw material and the sintered body.

Also provided is a sintered body that includes zirconia that contains a stabilizer and having a monoclinic fraction of 0.5% or more. Such a sintered body is produced by a method including using a powder that contains a stabilizer and zirconia with a monoclinic fraction of more than 70%, wherein monoclinic zirconia has a crystallite size of more than 23 nm and 80 nm or less.

The present invention provides a zirconia pre-sintered body that enables one visit treatment due to the short firing time and from which a zirconia sintered body having excellent translucency is obtained irrespective of the thickness, and a method for producing the zirconia pre-sintered body. The present invention is a method for producing a zirconia molded body, wherein the zirconia molded body comprises: zirconia; and a stabilizer capable of inhibiting a phase transformation of zirconia, at least a part of the stabilizer is undissolved in zirconia as a solid solution, and the method comprises press molding a mixed powder comprising zirconia and the stabilizer at a pressure of 175 MPa or more to obtain a zirconia molded body.

In order to provide a dielectric composition having high relative permittivity at a wide range of temperatures, the main component of a dielectric composition includes strontium and tantalum.

Provided are metal oxide ceramic materials and intermediate materials thereof (e.g., nanozirconia gels, nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles). The nanozirconia gels are formable gels. Also provided are methods of making and using the metal oxide materials and intermediate materials. The nanozirconia gels can be made using, for example, osmotic processing. The nanozirconia gels can be used to make nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental article. The nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles have desirable properties (e.g., optical properties and mechanical properties).

Provided are metal oxide ceramic materials and intermediate materials thereof (e.g., nanozirconia gels, nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles). The nanozirconia gels are formable gels. Also provided are methods of making and using the metal oxide materials and intermediate materials. The nanozirconia gels can be made using, for example, osmotic processing. The nanozirconia gels can be used to make nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental article. The nanozirconia green bodies, pre-sintered ceramic bodies, zirconia dental ceramic materials, and dental articles have desirable properties (e.g., optical properties and mechanical properties).

A composite ceramic including: a lithium garnet major phase; and a grain growth inhibitor minor phase, as defined herein. Also disclosed is a method of making composite ceramic, pellets and tapes thereof, a solid electrolyte, and an electrochemical device including the solid electrolyte, as defined herein.

The purpose of the present invention is to provide a zirconia-based porous body which can be pulverized in a relatively short time and in which performance deterioration caused by pulverization is suppressed. The present invention pertains to a zirconia-based porous body in which the total pore volume is at least 1.0 ml/g, the pore volume of pores having a diameter of 20-100 nm (exclusive of 100) is at most 0.3 ml/g, and the pore volume of pores having a diameter of 100-1000 nm is at least 0.5 ml/g.

Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes Al.sub.2O.sub.3 (alumina), WC (tungsten carbide) and ZrO.sub.2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al.sub.2O.sub.3; and (2) a grain boundary of crystal grains of the Al.sub.2O and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO.sub.2, and the balance being the Al.sub.2O.sub.3, and wherein the ZrO.sub.2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

This zirconia powder contains 2.5 to 3.5 mol % of yttria; has a specific surface area of 5 to 20 m.sup.2/g; and has crystal phases that include a monoclinic crystal phase percentage of 20 to 40% and a tetragonal crystal phase percentage of 60 to 80%. When the zirconia powder is molded under a mold pressure of 0.8 t/cm.sup.2 and then sintered under a condition of 2 hours at 1450° C. to obtain a sintered body, the sintered body has crystal phases that include a monoclinic crystal phase percentage of 1 to 3%, a tetragonal crystal phase percentage of 77 to 94%, and a cubic crystal phase percentage of 5 to 20%.

The present invention relates to a novel multi-layered zirconia dental blank comprising at least two reverse layers. Further, the invention relates to a process for the preparation of such a multi-layered zirconia dental blank. The invention also relates to the use of such a multi-layered zirconia dental blank for the production of a dental article. Preferred dental articles are artificial teeth, inlays, onlays, bridges, crowns, veneers, facings, crown frameworks, bridged frameworks, implants, abutments, copings or orthodontic appliances. Moreover, the invention relates to a process for producing a dental article out of such a multi-layered zirconia dental blank.