Provided is at least any of a layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. There is provided a layered body having a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer.

A Faraday rotator and an optical isolator having a high transmittance and a high Verdet constant are provided. The optical isolator includes at least a Faraday rotator that rotates a polarization plane of incident light in a non-reciprocal manner, a polarizer disposed on a light incident side of the Faraday rotator, and an analyzer disposed on a light exit side of the Faraday rotator. The Faraday rotator is made of an oxide containing ytterbium oxide (Yb.sub.2O.sub.3), and is manufactured by a ceramic manufacturing process, wherein the oxide is allowed to contain an oxide of a metal other than ytterbium, and the proportion of ytterbium in all metal atoms in the oxide is 80% or more.

There is provided at least any of a layered body which has a change in color tone and in which it is unnecessary to select a colorant and the content of the colorant in consideration of a difference in the sintering behavior between layers, a precursor thereof, or a method for producing these. Provided is a layered body which has a structure, in which two or more layers containing stabilizer-containing zirconia and a colorant are layered, and in which types and contents of the colorants contained in the layers are equal to each other, the layered body including at least: a first layer containing a colorant and zirconia which has a stabilizer content of higher than or equal to 3.3 mol %; and a second layer containing a colorant and zirconia which has a stabilizer content different from that of the zirconia contained in the first layer.

The invention relates to a method for producing a metal-ceramic substrate and to a furnace suitable for carrying out the method. With the method, a metal-ceramic substrate with increased thermal and current conductivity can be obtained. The method comprises the steps of providing a stack containing a ceramic body, a metal foil, and a solder material in contact with the ceramic body and the metal foil, the solder material comprising a metal having a melting point of at least 700° C., a metal having a melting point of less than 700° C., and an active metal, and heating the stack, the stack passing through a heating zone for heating.

The present invention relates to a method for producing a metal-ceramic substrate. The method has the following steps: providing a stack containing a ceramic body, a metal foil, and a solder material in contact with the ceramic body and the metal foil, wherein the solder material has: a metal having a melting point of at least 700° C., a metal having a melting point of less than 700° C., and an active metal; and heating the stack, wherein at least one of the following conditions is satisfied: the high temperature heating duration is no more than 60 min; the peak temperature heating duration is no more than 30 min; the heating duration is no more than 60 min.

A dielectric body includes a plurality of crystal grains of which a main component is barium titanate, and an additive including Zr, Eu and Mn. At least one of the plurality of crystal grains has a core-shell structure having a core and a shell. A Zr/Ti atomic concentration ratio is 0.02 or more and 0.10 or less. An Eu/Ti atomic concentration ratio is 0.001 or more and 0.03 or less. A Mn/Ti atomic concentration ratio is 0.005 or more and 0.05 or less. A total atomic concentration of the one or more rare elements is smaller than an atomic concentration of Eu when the dielectric body has the one or more rare earth elements. A median diameter of the plurality of crystal grains is 200 nm or more and 400 nm or less.

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.

The present invention discloses a polyimide-based composite carbon film with high thermal conductivity and a preparation method therefor. The preparation method includes: uniformly coating the surface of a polyimide-based carbon film with an aqueous graphene oxide solution, and then covering the same with another polyimide-based carbon film uniformly coated with an aqueous graphene oxide solution; repeating such operation; after the polyimide-based carbon films are dried, bonding the polyimide-based carbon films by means of graphene oxide so as to form a thick film; bonding the polyimide-based carbon films more tightly by means of further low-temperature hot pressing; and finally, obtaining a thick polyimide-based carbon film with high thermal conductivity by repairing defects by means of low-temperature heating pre-reduction and high-temperature and high-pressure thermal treatment. The thick polyimide-based carbon film with high thermal conductivity has a thickness greater than 100 μm and an in-plane thermal conductivity of even reaching 1700 W/mK or above.

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.

The present invention relates to a ceramic, to a process for preparing the ceramic and to the use of the ceramic as a dielectric in a capacitor.