The invention relates to a copper-ceramic composite comprising: a ceramic substrate; and a copper or copper alloy coating on the ceramic substrate, the copper or copper alloy having grain sizes of 10 μm to 300 μm.

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.

In a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, dislocation defect portions exists inside at least some of the silicon nitride crystal grains. A percentage of a number of the at least some of the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in any cross section or surface of the silicon nitride sintered body is not less than 50% and not more than 100%. It is favorable that a plate thickness of the silicon nitride substrate, in which the silicon nitride sintered body is used, is within the range not less than 0.1 mm and not more than 0.4 mm. The TCT characteristics can be improved by using the silicon nitride substrate in the silicon nitride circuit board.

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.

Polycrystalline diamond cutters and methods of making thereof are described. The cutters include a substrate and a diamond body. The diamond body includes diamond particles spatially arranged according to a gradient of particle sizes. The methods include steps of suspending diamond particles in a liquid and allowing their sedimentation according to a gradient of particle sizes resulting in regions spatially arranged axially and/or radially in which a majority of diamond particles in one region have lower average sizes or average diameters comparative to a majority of diamond particles in a second region.

A support substrate 2 is a polycrystalline SiC substrate formed of polycrystalline SiC. Assuming that one of the two sides of the polycrystalline SiC substrate is a first side and that the other side is a second side, a substrate grain size change rate of the polycrystalline SiC substrate, which is a value obtained by dividing a difference between the average value of crystal grain sizes of the polycrystalline SiC on the first side and the average value of crystal grain sizes of the polycrystalline SiC on the second side by a thickness of the polycrystalline SiC substrate, is 0.43% or less. A radius of curvature of the polycrystalline SiC substrate is 142 m or more.

Fused tuckstone defining lower and upper surfaces. The lower surface includes a support surface to rest on metallic structure of a glass furnace, a tank surface intended to face an upper edge of a tank of the furnace, and a lower transition surface connecting the support and tank surfaces. The upper surface includes a superstructure surface to receive a side wall of a superstructure of the furnace and an upper transition surface connecting the superstructure and lower surfaces. At least a part of the lower transition surface has a crystal density of more than four times the crystal density at a depth of 4 centimeters below the lower transition surface, a crystal density being evaluated by the number of crystals having a surface area of more than 12 m.sup.2 per mm.sup.2 of surface after polishing, the crystal density at the depth being evaluated after cutting of the tuckstone.

The invention relates to a copper/ceramic composite comprisinga ceramic substrate which contains aluminum oxide, a coating which lies on the ceramic substrate and which is made of copper or a copper alloy, wherein the copper or the copper alloy has a particle size number distribution with a median value d.sub.50, an arithmetic mean value d.sub.arith, and a symmetry value S(Cu)=d.sub.50/d.sub.arith; the aluminum oxide has a particle size number distribution with a median value d.sub.50, an arithmetic mean value d.sub.arith, and a symmetry value S(Al.sub.2O.sub.3)=d.sub.50/d.sub.arith; and S(Al.sub.2O.sub.3) and S(Cu) satisfy the following condition: 0.7<S(Al.sub.2O.sub.3)/S(Cu)1.4.

A sputtering target contains an oxide sinter that contains indium (In) element, tin element (Sn), zinc element (Zn), X element and oxygen, that further contains a spinel structure compound represented by Zn.sub.2SnO.sub.4, and that satisfies a formula (1) representing an atomic ratio of the elements.

0.001X/(In+Sn+Zn+X)0.05(1)

In the formula (1), In, Zn, Sn, and X represent contents of the In element, Zn element, Sn element, and X element in the oxide sinter, respectively, and the X element is at least one element selected from Ge, Si, Y, Zr, Al, Mg, Yb and Ga.

A sintered material includes cubic boron nitride grains and a binder, a grain size D50 of the cubic boron nitride grains when a cumulative value of the cubic boron nitride grains is 50% in an area-based grain size distribution being more than 0.5 m and less than or equal to 5 m, more than or equal to 70 volume % and less than or equal to 98 volume % of the cubic boron nitride grains being included in the sintered material, the binder being composed of A.sub.1-xCr.sub.xN, where 0x1, and a remainder, the remainder being composed of at least one of a first element and a compound including the first element and a second element, the first element being one or more elements selected from a group consisting of W, Co, Ni, Mo, Al, and Cr, the second element being one or more elements selected from a group consisting of nitrogen, carbon, oxygen, and boron.