A method of making a polycrystalline cubic boron nitride (PCBN), material is provided. The matrix precursor powder comprises an aluminium compound. The method comprises mixing matrix precursor powder comprising particles having an average particle size no greater than 250 nm, with between 30 and 40 volume percent of cubic boron nitride (cBN) particles having an average particle size of at least 4 μm, and then spark plasma sintering the mixed particles. The spark plasma sintering occurs at a pressure of at least 500 MPa, a temperature of no less than 1050° C. and no more than 1500° C. and a time of no less than 1 minute and no more than 3 minutes.

A cubic boron nitride sintered material includes: more than or equal to 85 volume % and less than 100 volume % of cubic boron nitride grains; and a remainder of a binder, wherein the binder includes WC, Co and an Al compound, and when a TEM-EDX is used to analyze an interface region including an interface at which the cubic boron nitride grains are adjacent to each other, oxygen exists on a whole or part of the interface, and a width D of a region in which the oxygen exists is more than or equal to 0.1 nm and less than or equal to 10 nm.

A cutting tool comprises a rake face and a flank face, the cutting tool being composed of a substrate made of a cubic boron nitride sintered material and a coating provided on the substrate, the coating including a MAlN layer, when a cross section of the MAlN layer is subjected to an electron backscattering diffraction image analysis to determine a crystal orientation of each of the crystal grains of the M.sub.xAl.sub.1−xN and a color map is created based thereon, then on the color map, the flank face having the MAlN layer occupied in area by 45% to 75% by crystal grains of the M.sub.xAl.sub.1−xN having a (111) plane with a normal thereto extending in a direction within 25 degrees with respect to a direction in which a normal to the flank face extends, the MAlN layer having a residual stress of −2 GPa to −0.1 GPa.

Provided is a cubic boron nitride sintered body including more than or equal to 85 volume percent and less than 100 volume percent of cubic boron nitride particles, and a remainder of a binder, wherein the binder contains WC, Co, and an Al compound, the binder contains W.sub.2Co.sub.21B.sub.6, and, when I.sub.A represents an X-ray diffraction intensity of a (111) plane of the cubic boron nitride particles, I.sub.B represents an X-ray diffraction intensity of a (100) plane of the WC, and I.sub.C represents an X-ray diffraction intensity of a (420) plane of the W.sub.2Co.sub.21B.sub.6, a ratio I.sub.C/I.sub.A of the I.sub.C to the I.sub.A is more than 0 and less than 0.10, and a ratio I.sub.C/I.sub.B of the I.sub.C to the I.sub.B is more than 0 and less than 0.40.

The object of the present invention is to provide a large-sized gallium nitride-based sintered body having a small oxygen amount and high strength, a large-sized gallium nitride-based sintered body having a small oxygen amount and containing a dopant, to obtain a highly crystalline gallium nitride thin film which has become a n-type or p-type semiconductor by a dopant, and methods for producing them.

A gallium nitride-based sintered body, which has an oxygen content of at most 1 atm % and an average particle size (D50) of at least 1 μm and at most 150 μm.

Disclosed is a refractory product for casting of steel, which is capable of forming a dense surface layer which is high in terms of a slag infiltration suppressing ability and strong, in a surface region thereof efficiently or sufficiently or in an optimum state. The refractory product contains 1 mass % or more of free carbon, and 2 mass % to 15 mass % of an aluminum component as metal, with the remainder comprising a refractory material as a main composition, wherein the refractory product has a permeability of 1×10.sup.−16 m.sup.2 to 15×10.sup.−16m.sup.2.

A sintered material includes a cubic boron nitride, a zirconium-containing oxide, a zirconium-containing nitride, and an aluminum-containing oxide, wherein the zirconium-containing nitride includes both or one of ZrN and ZrON, and the aluminum-containing oxide includes a type Al.sub.2O.sub.3.

A moldable green-body composite includes milling silicon nitride powder with a solvent and adding a surface modifier to the milled slurry to modify a surface of the silicon nitride particles. A polysiloxane in a solvent and a binder are also added to create a green body slurry. The solvents may be polar or non-polar solvents. A sintering aid, such as yttria-alumina, may be added to the slurry as well. A reduced density silicon nitride ceramic is made from the moldable green-body composite by molding the moldable green-body composite in a mold and curing at a curing temperature to convert the moldable green-body composite to a converted composite. The converted composite can then be sintered to form a reduced density silicon nitride ceramic that has a smooth surface finish and requires no post machining or polishing. The reduced density silicon nitride ceramic may also have very good dielectric properties.

A sputtering target containing silicon nitride (Si.sub.3N.sub.4) with reduced specific resistance of is provided. A sputtering target including Si.sub.3N.sub.4, SiC, MgO and TiCN, wherein a specific resistance of the sputtering target is 10 mΩ.Math.cm or less.

A cubic boron nitride sintered material includes: more than or equal to 80 volume % and less than or equal to 96 volume % of cubic boron nitride grains; and a binder, wherein the binder includes tungsten carbide, cobalt, and an aluminum compound, and Ha/Hb≥0.40 is satisfied, where Hb represents a hardness of the cubic boron nitride sintered material and Ha represents a hardness of the cubic boron nitride sintered material after performing acid treatment onto the cubic boron nitride sintered material to substantially remove the binder in the cubic boron nitride sintered material.