A gas nozzle having a fired surface excellent in particle reduction effect is provided. The gas nozzle 1 is a columnar gas nozzle made of sintered ceramics, provided with at least one through-hole 2 through which gas flows. The entire inner surface 2a of the through-hole 2 and the end face 1A on which outlet 2b of the through-hole 2 is provided are both fired surfaces. The inner surface 2a of the through-hole 2 has a first region A in the vicinity of the outlet 2b and a second region B which is located at a further position than the first region A. The average crystal grain size in the first region A is formed to be smaller than the average crystal grain size in the second region B.

A heat dissipation member includes a thermal radiation ceramic material, and the thermal radiation ceramic material contains silicon nitride and boron nitride as main components. The ratio of the mass of boron nitride to the mass of silicon nitride and boron nitride is 10 mass % to 40 mass %.

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.

A paste for ceramic 3D shaping according to the present invention is a paste for ceramic 3D shaping containing a curable resin and inorganic particles, in which the inorganic particles contain ceramic particles and glass particles.

A paste for ceramic 3D shaping according to the present invention is a paste for ceramic 3D shaping containing a curable resin and inorganic particles, in which the inorganic particles contain ceramic particles and glass particles.

In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

A dielectric composition contains a complex oxide represented by a composition formula of Bi.sub.xZn.sub.yNb.sub.zO.sub.1.75+δ. x+y+z=1.00. x<0.20. 0.20≤y≤0.50. 0.25≤x/z. A dielectric composition contains a complex oxide represented by a composition formula of Bi.sub.xZn.sub.yNb.sub.zO.sub.1.75+δ. x+y+z=1.00. 0.20≤y≤0.50. 1.5<x/z≤3.0. z<0.25.

A polycrystalline super hard construction comprises a body of polycrystalline super hard material and a substrate bonded to the body along an interface. The substrate a first end surface forming the interface, the first end surface comprising a projection extending from the body of the substrate into the body of super hard material towards the cutting face, the body of polycrystalline material extending around the projection. The body of polycrystalline material comprises a first region more thermally stable than a second region, the first region comprising an annular portion located around the projection, the second region extending between and bonding the first region to the substrate. The first region has a thickness from the cutting face along the peripheral side edge to the interface of at least around 3 mm and a portion of the projection has a thickness measured in a plane extending along the longitudinal axis of at least around 3 mm.

A polycrystalline super hard construction comprises a body of polycrystalline super hard material and a substrate bonded to the body along an interface. The substrate a first end surface forming the interface, the first end surface comprising a projection extending from the body of the substrate into the body of super hard material towards the cutting face, the body of polycrystalline material extending around the projection. The body of polycrystalline material comprises a first region more thermally stable than a second region, the first region comprising an annular portion located around the projection, the second region extending between and bonding the first region to the substrate. The first region has a thickness from the cutting face along the peripheral side edge to the interface of at least around 3 mm and a portion of the projection has a thickness measured in a plane extending along the longitudinal axis of at least around 3 mm.

A method includes molding a raw material powder containing a ceramic powder and a thermoplastic resin having a glass transition temperature higher than room temperature into a shape by isostatic pressing and in which a raw material powder slurry is prepared by adding the ceramic powder and the thermoplastic resin to a solvent so that the thermoplastic resin is 2% by weight or more and 40% by weight or less with respect to a total weight of the ceramic powder and the thermoplastic resin, a cast-molded body is to formed by wet-casting the raw material powder slurry into a shape, dried, and subjected to first-stage isostatic press molding at a temperature lower than the glass transition temperature of the thermoplastic resin, then this first-stage press-molded body is heated to the glass transition temperature of the thermoplastic resin or above, and warm isostatic press (WIP) molding is performed.