A dielectric composition and a multilayer capacitor including the same are provided. The dielectric composition includes a BaTiO.sub.3-base main component, a first subcomponent including an Nb component and a Gd component, a second subcomponent including an Mg component, and a third subcomponent including a Ba component and a Ca component. The first subcomponent is included in an amount of 4 moles or less per 100 moles of the main component. In the first subcomponent, a molar content of Nb and a molar content of Gd satisfy 0.33≤Nb/Gd, and in the third subcomponent, a molar content of Ba and a molar content of Ca satisfy 0.2≤Ca/(Ba+Ca).

A multilayer electronic component includes a body including a plurality of dielectric layers, wherein, wherein a central portion of the capacitance formation portion is Aa, a boundary portion of the capacitance formation portion, adjacent to the cover portions, is Ab, a dielectric grain size corresponding to the top 50% of dielectric grains, in order of enlargement, from the smallest grain size, among a plurality of dielectric grains included in Aa, is D50a, and a dielectric grain size corresponding to the top 50% of dielectric grains, in order of enlargement, from the smallest grain size, among a plurality of dielectric grains included in Ab, is D50b, D50a satisfies 190 nm or less and D50b satisfies 120 nm or greater.

A zirconia sintered body may excel in translucency, strength, and linear light transmittance with no use of an HIP device, and a zirconia molded body and a zirconia pre-sintered body from which such a zirconia sintered body can be obtained. A zirconia molded body may include zirconia particles with 2.0 to 9.0 mol % yttria, an average primary particle diameter of 60 nm or less, and 0.5 mass % or less zirconia particles having a particle diameter >100 nm, wherein the zirconia molded body has ΔL*(W−B) of 5+ through a thickness of 1.5 mm. A zirconia pre-sintered body may include 2.0 to 9.0 mol % yttria, and have a ΔL*(W−B) of 5+ through a thickness of 1.5 mm. A zirconia sintered body may include: a fluorescent agent; 2.0 to 9.0 mol % yttria, and have a linear light transmittance of 1% or more through a thickness of 1.0 mm.

Provided is a method for producing a calcium carbonate sintered body whereby a good sintered body can be obtained without having to use any sintering aid. A method for producing a calcium carbonate sintered body includes the steps of: compacting calcium carbonate to make a green body; heating the green body under a condition of a temperature of 500° C. or lower to remove an organic component contained in the green body; and sintering the green body under conditions of a carbon dioxide atmosphere and a temperature of 450° C. or higher to obtain a calcium carbonate sintered body.

A cBN-based ultra-high pressure sintered body contains cBN particles and a binder phase. The binder phase contains at least one of a nitride or oxide of Al or a nitride, carbide, or carbonitride of Ti, and a metal boride having an average particle diameter of 20 to 300 nm is dispersed in an amount of 0.1 to 5.0 vol % in the binder phase. The metal boride includes a metal boride (B) containing at least one of Nb, Ta, Cr, Mo, and W as a metal component and containing no Ti and a metal boride (A) containing only Ti as a metal component. In a case where a ratio (vol %) of the metal boride (A) in the metal boride is represented by V.sub.a and a ratio (vol %) of the metal boride (B) is represented by V.sub.b, a ratio of V.sub.b/V.sub.a is 0.1 to 1.0.

Certain embodiments of the present disclosure relate to ceramic materials with high thermal shock resistance and high erosion resistance. In one embodiment, a ceramic material is formed from a composition comprising Al.sub.2O.sub.3, MgO, SiO.sub.2.

A substrate for mounting a light-emitting element according to the present disclosure contains a crystal particle of aluminum oxide and is composed of an alumina-based ceramic that contains 97% by mass or more of Al as a value of an Al.sub.2O.sub.3 equivalent among 100% by mass of all components thereof. An average value of an equivalent circle diameter of the crystal particle is 1.1 μm or greater and 1.8 μm or less and a standard deviation of an equivalent circle diameter thereof is 0.6 μm or greater and 1.4 μm or less.

A sintered composite ceramic, includes: a lithium-garnet major phase; and a lithium dendrite growth inhibitor minor phase, such that the lithium dendrite growth inhibitor minor phase has a Li-metal oxide in a range of >0-10 wt. % based on the total weight of the sintered composite ceramic.

A porous refractory article including greater than 90 wt % coal combustion fly ash. The coal combustion fly ash is in the form of an interconnected particulate lattice structure, and wherein greater than 50% by volume of the coal combustion fly ash particles within the particulate lattice structure have a particle size of greater than 150 μm. The article has: (a) an apparent porosity of from 30% to 50%, (b) a porosity such that the maximum pore size is less than 500 μm; (c) a cold crushing strength of at least 4.0 MPa; and (d) a thermal conductivity of less than 1.5 W/(m.Math.K).

A sintered composite ceramic, including: a lithium-garnet major phase; and a grain growth inhibitor minor phase, such that the grain growth inhibitor minor phase has a metal oxide in a range of 0.1 wt. % to 10 wt. % based on the total weight of the sintered composite ceramic.