The invention relates to a drilling tool (50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (56) with a front surface (60), and to a drill head (58) with at least one cutting edge (66), which is firmly connected, such as soldered, to the drill shaft (56). In order to make available a drilling tool of the type mentioned at the start, which has a broad range of application and is simple to produce, it is provided that the drill head (58) is formed from a composite material with exclusively two layers (38), namely a hard metal layer (36) and an ultra-hard layer (38) which is connected to the hard metal layer (36) and preferably formed from polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (56) and that the at least one cutting edge (66) is formed by the ultra-hard layer (38), and a drill bit (62) such as a centering tip is formed by the hard metal layer (36).

The disclosure relates to cubic boron nitride inserts for machining iron-based workpieces, as well as related methods and apparatuses. The insert includes a cutting element containing cubic boron nitride (cBN) in an amount in a range of 50 wt. % to 95 wt. % based on the cutting element, and a binder containing at least one of (i) alumina (Al.sub.2O.sub.3) and a manganese material (e.g., an oxide such as MnO.sub.x) and (ii) zirconia (ZrO.sub.2). The insert can be used for various machining processes, for example turning or boring. Suitable workpieces include iron-based materials or ferrous alloys, for example a cast iron such as compacted graphite iron (CGI).

A method of producing a cubic boron nitride sintered material includes: forming an organic cubic boron nitride powder by attaching an organic substance onto a cubic boron nitride source material powder; preparing a powder mixture including more than or equal to 85 volume % and less than 100 volume % of the organic cubic boron nitride powder and a remainder of a binder source material powder by mixing the organic cubic boron nitride powder and the binder source material powder, the binder source material powder including WC, Co and Al; and obtaining the cubic boron nitride sintered material by sintering the powder mixture.

Object: To provide a cBN sintered compact having high wear resistance, and a cutting tool having high wear resistance that uses the cBN sintered compact. Solution: A cBN sintered compact (1) including 50 vol. % or greater of cBN particles (2); and a binder phase (4) including Co; wherein in the binder phase (4), intra-phase particles (8) including Co.sub.aW.sub.b (where 0≤a≤0.95 and 0.05≤b≤1) are present. Additionally, a cutting insert (20) or similar cutting tool either includes a cBN tip (25) made from the cBN sintered compact (1) or is entirely made from the cBN sintered compact (1). The cBN sintered compact (1) and the cutting insert (20) or similar cutting tool have increased wear resistance.

A cBN sintered material cutting tool includes a cutting tool body that is made of a sintered material including cubic boron nitride particles and a binder phase, in which: an average particle size of the cBN particles is 0.5 μm or less and a content ratio of the cBN particles in the sintered material is 35 vol % to 80 vol %; and the binder phase includes 1.0 vol % to 20 vol % of an Al compound, an average particle size of the Al compound present in the binder phase is 300 nm or less, and a value of a ratio (a value of S.sub.N/S.sub.O; area ratio) of a content S.sub.N of nitrogen (N) included in the Al compound to a content S.sub.O of oxygen (O) included in the Al compound is 1.1 to 5.

A coated cutting tool includes a substrate of cemented carbide, cermet, cBN, ceramics or HSS and a coating of a nitride layer, which is a High Power Impulse Magnetron Sputtering (HIPIMS) deposited layer of a nitride of one or more of Ti, Zr, Hf, V, Ta, Nb, Cr, Si and Al, and a HIPIMS-deposited oxide layer being an (Al.sub.aMe.sub.1−a).sub.2O.sub.3 layer, 0.05≤a≤1, wherein Me is one or more of Ti, Mg, Ag, Zr, Si, V, Fe, Hf, B and Cr. The oxide layer is situated above the nitride layer. Also, a method is disclosed for producing a coated cutting tool having the nitride layer and oxide layer, the nitride layer and the oxide layer being deposited by a HIPIMS process.

A cutting insert comprises: a body; and a blade fixed to the body and made of a polycrystalline cubic boron nitride including 98.5% by volume or more of cubic boron nitride, the blade having a rake face and a flank face, the rake face and the flank face meeting each other and thus forming a ridge line which serves as a cutting edge, the rake face being provided with a land surface extending along the cutting edge, and a chip breaker disposed on a side opposite to the cutting edge with the land surface therebetween and also having a recess contiguous to the land surface.

A method of producing a cubic boron nitride sintered material includes: forming an organic cubic boron nitride powder by attaching an organic substance onto a cubic boron nitride source material powder; preparing a powder mixture including more than or equal to 85 volume % and less than 100 volume % of the organic cubic boron nitride powder and a remainder of a binder source material powder by mixing the organic cubic boron nitride powder and the binder source material powder, the binder source material powder including WC, Co and Al; and obtaining the cubic boron nitride sintered material by sintering the powder mixture.

A polycrystalline cubic boron nitride comprising 96% by volume or more of cubic boron nitride, wherein the cubic boron nitride has a dislocation density of more than 8×10.sup.15/m.sup.2, the polycrystalline cubic boron nitride comprises a plurality of crystal grains, and the plurality of crystal grains have a median diameter d50 of an equivalent circle diameter of less than 100 nm.

A polycrystalline cubic boron nitride comprising 98.5% by volume or more of cubic boron nitride, wherein the cubic boron nitride has a dislocation density of more than 8×10.sup.15/m.sup.2, the polycrystalline cubic boron nitride comprises a plurality of crystal grains, and the plurality of crystal grains have a median diameter d50 of an equivalent circle diameter of 0.1 μm or more and 0.5 μm or less.