A refractory article including a body having central opening extending through at least a portion of the body, the central opening having a receiving surface having a convex curvature. In an embodiment, the body can include a coupling protrusion extending from a portion of an upper surface of the body and a coupling depression on a portion of a bottom surface of the body.

A composition comprises a zirconia powder, in which 55% or more thereof is monoclinic, and a stabilizer capable of suppressing phase transition of zirconia. An average particle diameter of zirconia particles and particles of the stabilizer is 0.06 μm to 0.17 μm. At least a portion of the stabilizer does not form a solid solution with zirconia.

A composition comprises a zirconia powder, in which 55% or more thereof is monoclinic, and a stabilizer capable of suppressing phase transition of zirconia. An average particle diameter of zirconia particles and particles of the stabilizer is 0.06 μm to 0.17 μm. At least a portion of the stabilizer does not form a solid solution with zirconia.

Process for treating a porous dental zirconia block with a coloring solution, the process comprising the steps of providing a porous dental zirconia block having two opposing surfaces, surface U and surface L, treating the upper surface U of the porous dental zirconia block with a coloring solution A.sub.1, wherein the coloring solution is provided with a volume VA.sub.1, turning the porous dental zirconia block around, treating the lower surface L with a coloring solution A.sub.2 which is provided with a volume VA.sub.2. wherein the coloring solutions A.sub.1 and A.sub.2 comprise a solvent and coloring ions, wherein the volume of at least one of the coloring solutions A.sub.1 or A.sub.2 is applied in portions, wherein the following condition is met: Vo=ΣV.sub.AX, with x≥2, with Vo being the overall amount of coloring solution used to infiltrate the porous dental zirconia block.

Process for treating a porous dental zirconia block with a coloring solution, the process comprising the steps of providing a porous dental zirconia block having two opposing surfaces, surface U and surface L, treating the upper surface U of the porous dental zirconia block with a coloring solution A.sub.1, wherein the coloring solution is provided with a volume VA.sub.1, turning the porous dental zirconia block around, treating the lower surface L with a coloring solution A.sub.2 which is provided with a volume VA.sub.2. wherein the coloring solutions A.sub.1 and A.sub.2 comprise a solvent and coloring ions, wherein the volume of at least one of the coloring solutions A.sub.1 or A.sub.2 is applied in portions, wherein the following condition is met: Vo=ΣV.sub.AX, with x≥2, with Vo being the overall amount of coloring solution used to infiltrate the porous dental zirconia block.

Process for treating a porous dental zirconia block with a coloring solution, the process comprising the steps of providing a porous dental zirconia block having two opposing surfaces, surface U and surface L, treating the upper surface U of the porous dental zirconia block with a coloring solution A.sub.1, wherein the coloring solution is provided with a volume VA.sub.1, turning the porous dental zirconia block around, treating the lower surface L with a coloring solution A.sub.2 which is provided with a volume VA.sub.2. wherein the coloring solutions A.sub.1 and A.sub.2 comprise a solvent and coloring ions, wherein the volume of at least one of the coloring solutions A.sub.1 or A.sub.2 is applied in portions, wherein the following condition is met: Vo=ΣV.sub.AX, with x≥2, with Vo being the overall amount of coloring solution used to infiltrate the porous dental zirconia block.

A rim-rotor assembly has an annular structure including a composite rim and a hub. Blades project from the hub, tips of the blades contacting the annular structure, the blades configured to be loaded in compression against the annular structure. A thermal barrier is in the annular structure, the thermal barrier defining at least part of a radially inward surface of the annular structure. The tips of the blades contact the thermal barrier, the thermal barrier being a thermal barrier coating.

A rim-rotor assembly has an annular structure including a composite rim and a hub. Blades project from the hub, tips of the blades contacting the annular structure, the blades configured to be loaded in compression against the annular structure. A thermal barrier is in the annular structure, the thermal barrier defining at least part of a radially inward surface of the annular structure. The tips of the blades contact the thermal barrier, the thermal barrier being a thermal barrier coating.

A method for producing a zirconia sintered body includes: heating a zirconia molded body or a zirconia pre-sintered body, the heating includes a temperature increasing step, and a rate of temperature increase in a temperature region from a temperature at which the zirconia starts to shrink to a temperature at which the zirconia finishes shrinking in the temperature increasing step is adjusted to enable the zirconia molded body or the zirconia pre-sintered body to shrink at substantially a constant rate during temperature increase in each of zones of when the temperature region is evenly divided into a plurality of zones of specific temperature ranges.

A method for producing a zirconia sintered body includes: heating a zirconia molded body or a zirconia pre-sintered body, the heating includes a temperature increasing step, and a rate of temperature increase in a temperature region from a temperature at which the zirconia starts to shrink to a temperature at which the zirconia finishes shrinking in the temperature increasing step is adjusted to enable the zirconia molded body or the zirconia pre-sintered body to shrink at substantially a constant rate during temperature increase in each of zones of when the temperature region is evenly divided into a plurality of zones of specific temperature ranges.