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.

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.

Provided is a cutting tool including a base material and a coating layer provided on the base material, the coating layer including a titanium carbonitride layer provided on the base material, an intermediate layer provided on the titanium carbonitride layer in contact therewith, and an alumina layer provided on the intermediate layer in contact therewith, the intermediate layer being composed of a compound made of titanium, carbon, oxygen, and nitrogen, the intermediate layer having a thickness of more than 1 μm, when P.sub.N1 atomic % represents an atomic ratio of the nitrogen in an interface between the intermediate layer and the alumina layer, and P.sub.N2 atomic % represents an atomic ratio of the nitrogen at a point A away from the interface by 1 μm on a side of the intermediate layer, a ratio P.sub.N1/P.sub.N2 of the P.sub.N1 to the P.sub.N2 being more than or equal to 1.03.

A coated cutting tool for chip forming machining of metals includes a substrate having a surface coated with a chemical vapour deposition (CVD) coating. The substrate is coated with a coating having a layer of α-Al.sub.2O.sub.3, wherein the α-Al.sub.2O.sub.3 layer exhibits a texture coefficient TC(0 0 12)≥7.2 and wherein the ratio of I(0 0 12)/I(0 1 14)≥0.8. The coating further includes a MTCVD TiCN layer located between the substrate and the α-Al.sub.2O.sub.3 layer. The MTCVD TiCN layer exhibits a pole figure, as measured by EBSD, in a portion of the MTCVD TiCN layer parallel to the outer surface of the coating and less than 1 μm from the outer surface of the MTCVD TiCN, wherein a pole plot based on the data of the pole figure, with a bin size of 0.25° over a tilt angle range of 0°≤β≤45° from the normal of the outer surface of the coating shows a ratio of intensity within β≤15° tilt angle to the intensity within 0°≤β≤45° of ≥45%.

A method for producing a coated cutting tool includes depositing on every flank face and every rake face of the cutting tool an Al.sub.2O.sub.3 layer by a HIPIMS process during two-fold or three-fold rotation of the substrates, at a substrate temperature ≥350° C. but <600° C., the deposited Al.sub.2O.sub.3 layer including α-Al.sub.2O.sub.3.

A surface-coated cutting tool according to the present invention includes a tool body and a hard coating layer including a complex carbonitride layer containing a small amount of chlorine and (Ti.sub.(1-x)Zr.sub.xyHf.sub.x(1-y))(N.sub.(1-z)C.sub.z) (0.10≤x≤0.90, 0<y≤1.0, 0.08<z<0.60), a ZrHf and C content ratios in cycles, a cycle distance between a maximum ZrHf content point and an adjacent minimum ZrHf content point and a cycle distance between a maximum C content point and an adjacent minimum C content point are 5 to 100 nm, an average value of content ratio differences Δx and Δz is 0.02 or more, a distance between the maximum ZrHf content point and the maximum C content point is ⅕ or less of the distance between a maximum content point and a minimum content point of adjacent ZrHf components, and a composition fluctuation structure is 10% or more.

A cutting tool includes: a substrate; a hard layer provided on the substrate; and a titanium carbonitride layer provided on the hard layer, wherein a thickness of the titanium carbonitride layer is more than or equal to 2 μm, a hardness of the titanium carbonitride layer at a room temperature is more than or equal to 35 GPa, and a Young's modulus of the titanium carbonitride layer at the room temperature is more than or equal to 800 GPa.

A coated tool may include a base member and a coating layer located on the base member. The coating layer may include a plurality of AlTi layers and a plurality of AlCr layers. The AlTi layers may include at least one kind selected from nitride, carbide or carbonitride, each including aluminum and titanium. The AlCr layers may include at least one kind selected from nitride, carbide or carbonitride, each including aluminum and chromium. The coating layer may include a laminate structure in which the AlTi layers and the AlCr layers are alternately laminated one upon another. The AlCr layers may include a first AlCr layer and a second AlCr layer located farther away from the base member than the first AlCr layer. A content ratio of chromium in the second AlCr layer may be higher than a content ratio of chromium in the first AlCr layer.

A cutting tool comprises a substrate and an AlTiN layer, the AlTiN layer including a first major surface and a second major surface, the AlTiN layer including a first region having a distance of 0 nm or more and 30 nm or less from the first major surface and having a maximum oxygen content ratio of more than 0 atomic % and less than 5 atomic %, a second region having a distance of more than 30 nm and 100 nm or less from the first major surface and having a maximum oxygen content ratio of 5 atomic % or more and 30 atomic % or less, and a third region having a distance of more than 100 nm and 150 nm or less from the first major surface and having a maximum oxygen content ratio of more than 0 atomic % and less than 5 atomic %.

A cutting tool comprises a substrate and an AlTiN layer, the AlTiN layer including a first major surface and a second major surface, the AlTiN layer including a first region having a distance of 0 nm or more and 30 nm or less from the first major surface and having a maximum oxygen content ratio of 30 atomic % or more, a second region having a distance of more than 30 nm and 100 nm or less from the first major surface and having a maximum oxygen content ratio of 5 atomic % or more and less than 30 atomic %, and a third region having a distance exceeding 100 nm from the first major surface and having a maximum oxygen content ratio of less than 5 atomic %.