The cubic boron nitride sintered material is a cubic boron nitride sintered material comprising: cubic boron nitride particles in an amount of 70 vol % or more and less than 100 vol %, and a bonding material, wherein the bonding material includes an aluminum compound, and includes cobalt as a constituent element; the cubic boron nitride sintered material has a first region in which a space between adjacent cubic boron nitride particles is 0.1 nm or more and 10 nm or less; and when the first region is analyzed by using an energy dispersive X-ray analyzer equipped with a transmission electron microscope, the atom % of aluminum in the first region is 0.1 or more.

Provided is a coated cutting tool having improved wear resistance and fracture resistance and a prolonged tool life. The coated cutting tool includes a substrate and a coating layer formed on the substrate. The coating layer includes a first layer containing Ti(C.sub.x1N.sub.1-x1) and a second layer containing (Ti.sub.1-y1Al.sub.y1)N, particles in the first layer have an average particle size of 5 nm or more and less than 100 nm, 1.0≤I(111)/I(200)≤20.0 in the first layer, the first layer has an average thickness of 5 nm or more and 1.0 μm or less, 0.1≤I(111)/I(200)≤1.0 in the second layer, particles in the second layer have an average particle size of more than 100 nm and 300 nm or less, and the second layer has an average thickness of 5 nm or more and 2.0 μm or less.

A coated cutting tool includes a substrate and a hard film on coated on the substrate. The hard film contains a complex nitride of Al and Cr. The hard film includes aggregates of columnar grains grown on the substrate along the thickness of the film. The nitride has an Al content of 60 atom % or more, a Cr content of 10 atom % or more, and a total content of Al and Cr of 90 atom % or more relative to the total amount of metal and metalloid elements. The complex nitride has the highest peak intensity assigned to crystal plane (311) of an fcc structure in X-ray diffractometry. In the hard film, the ratio of an X-ray diffraction intensity of plane (311) to the intensities of the other planes is 1.30 or more. A method and a system are also provided for manufacturing the coated cutting tool by chemical vapor deposition.

A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a plurality of first protrusions that project toward the Al.sub.2O.sub.3 layer, and a beam that extends in a direction intersecting a direction in which the first protrusions project, to connect the first protrusions. A cutting tool of the present disclosure is provided with: a holder extending from a first end toward a second end and including a pocket on a side of the first end; and the above-described coated tool located in the pocket.

A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a plurality of first protrusions that project toward the Al.sub.2O.sub.3 layer, and a beam that extends in a direction intersecting a direction in which the first protrusions project, to connect the first protrusions. A cutting tool of the present disclosure is provided with: a holder extending from a first end toward a second end and including a pocket on a side of the first end; and the above-described coated tool located in the pocket.

There is provided a cutting insert having a low possibility that chips roughen a machined surface of a workpiece in back turning. The cutting insert includes a rake surface, a peripheral side surface, a front cutting edge which is provided on a ridge of the rake surface and the peripheral side surface, and a main cutting edge which is provided on the ridge so as to be continuous with the front cutting edge and has an extension direction which forms an obtuse angle with an extension direction of the front cutting edge, the main cutting edge is curved into a U shape over an entire length of an effective edge range which functions as a cutting blade, and the deepest point of the U shape is positioned in a range closer to a side of a corner than a position which divides a straight line connecting both ends of the main cutting edge at a ratio of 2:1 from the side of the corner positioned adjacent to the front cutting edge.

A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a first composite protrusion including a first protrusion that projects toward the Al.sub.2O.sub.3 layer and a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects. A cutting tool of the present disclosure is provided with: a holder extending from a first end toward a second end and including a pocket on a side of the first end; and the above-described coated tool located in the pocket.

A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a first composite protrusion including a first protrusion that projects toward the Al.sub.2O.sub.3 layer and a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects. A cutting tool of the present disclosure is provided with: a holder extending from a first end toward a second end and including a pocket on a side of the first end; and the above-described coated tool located in the pocket.

A surface-coated cutting tool includes: a substrate including a rake face and a flank face; a first coating film that coats the rake face; and a second coating film that coats the flank face, wherein the first coating film includes a first composite nitride layer at a region d1 on the rake face, the second coating film includes a second composite nitride layer at a region d2 on the flank face, the first composite nitride layer includes Ti.sub.1-x1-y1Al.sub.x1Ta.sub.y1C.sub.α1N.sub.β1, the second composite nitride layer includes Ti.sub.1-x2-y2Al.sub.x2Ta.sub.y2C.sub.α2N.sub.β2.

A cutting tool includes: a substrate; and a coating film disposed on the substrate, wherein the coating film includes an α-Al.sub.2O.sub.3 layer, the α-Al.sub.2O.sub.3 layer includes a plurality of α-Al.sub.2O.sub.3 crystal grains, and has a TC(006) of more than 5 in texture coefficient TC(hkl), and an elastic modulus E1 of the α-Al.sub.2O.sub.3 layer at a room temperature and an elastic modulus E2 of the α-Al.sub.2O.sub.3 layer at 800° C. represent a relation of the following expression B-1:

0<{(E1−E2)/E1}×100<10  Expression B-1.