Abstract: A cutting tool comprising a substrate and a coating film disposed on the substrate, wherein the coating film comprises a first layer; the first layer has a thickness of 0.2 ?m or more and 9 ?m or less; the first layer is composed of Ti(1-x-y)AlxMyN, wherein M is at least one element such as zirconium; in the first layer, x and y change along the thickness direction of the first layer; a maximum value of x, xmax, is 0.20 or more and 0.70 or less; a minimum value of x, xmin, is 0 or more and 0.6 or less; xmax and xmin satisfy 0.01?xmax?xmin?0.7; a maximum value of y, ymax, is 0.01 or more and 0.20 or less; a minimum value of y, ymin, is 0 or more and 0.19 or less; and ymax and ymin satisfy 0.01?ymax?ymin?0.2.

Abstract: A composite sintered material includes a plurality of diamond grains, a plurality of cubic boron nitride grains, and a remainder of a binder phase, wherein the binder phase includes cobalt, a content of the cubic boron nitride grains in the composite sintered material is more than or equal to 3 volume % and less than or equal to 40 volume %, and an average length of line segments extending across continuous cubic boron nitride grains in appropriately specified straight lines extending through the composite sintered material is less than or equal to a length three times as large as an average grain size of the cubic boron nitride grains.

Abstract: The outer peripheral surface is provided with a first margin contiguous to each of the cutting edge and the flank face, and a second margin that is located on the rear side with respect to the first margin in a rotation direction and that is separated from each of the flank face and the thinning face. An outer peripheral portion of the first margin and an outer peripheral portion of the second margin have respective back tapers having the same angle. In a direction parallel to the axial line, a distance between a front end of the first margin and a front end of the second margin is more than or equal to 3 mm and less than or equal to 5 mm.

Abstract: A reamer is rotated about a central axis and has, in a direction along a central axis, a tool front end and a tool rear end that is an end opposite to the tool front end. The reamer includes a blade on a tool front end side. The blade has, on a circumferential surface, a chamfered cutting edge located on the tool front end side, a circumferential cutting edge contiguous to an end of the chamfered cutting edge on a tool rear end side, and a margin that is a surface contiguous to the circumferential cutting edge. The circumferential cutting edge includes a front end portion between a first position and a second position, the first position being an end on a chamfered cutting edge side, the second position having a distance of 1 mm from the first position in a direction of extension of the circumferential cutting edge.

Abstract: The boundary flow path is constituted of a pair of boundary wall surfaces facing each other in a first cross section intersecting each of the first flow path, the boundary flow path, and the second flow path. An inclination of a tangent to at least one of the pair of boundary wall surfaces is continuously changed. In a second cross section perpendicular to a direction in which coolant flows, a lateral width of the first flow path is larger than a longitudinal width of the first flow path and a lateral width of the second flow path is larger than a longitudinal width of the second flow path when a longitudinal direction represents a direction in which the pair of boundary wall surfaces face each other and a lateral direction represents a direction perpendicular to the longitudinal direction.

Abstract: A ridgeline between the thinning face and the flank face includes a first thinning portion contiguous to the outer cutting edge, and a second thinning portion contiguous to the first thinning portion. When viewed in a direction along the central axis, the first thinning portion is linear and the second thinning portion is curved. When viewed in the direction along the central axis, the first thinning portion, and a boundary between the first thinning portion and the second thinning portion are located rearward in a rotational direction relative to a first straight line, and are located forward in the rotational direction relative to a second straight line, the first straight line being a straight line passing through the central axis and parallel to the first thinning portion, and the second straight line being a straight line perpendicular to the first straight line.

Abstract: Provided is a cutting tool that can have a long tool life even when used to cut soft metals in particular. The cutting tool comprises a base body and a hard carbon film arranged on the base body, the hard carbon film includes an amorphous phase and a graphite phase, the density of the hard carbon film is no less than 2.5 g/cm3 and no more than 3.5 g/cm3, the degree of crystallinity of the hard carbon film is no more than 6.5%, and the average coordination number of the amorphous phase is no less than 2.5 and no more than 4.

Abstract: Provided is a cutting tool comprising a base body and a hard carbon film arranged on the base body, in which, when the cross section of the hard carbon film is observed using a high angle annular dark field scanning transmission electron microscope, the area proportion of black regions with an equivalent circle diameter of 10 nm or more is 0.7% or less, and the hard carbon film has a hydrogen content of 5 atom% or less.

Abstract: A cubic boron nitride sintered material includes: more than or equal to 20 volume % and less than 80 volume % of cubic boron nitride grains; and more than 20 volume % and less than or equal to 80 volume % of a binder phase, and when a carbon content is measured from a cubic boron nitride grain into the binder phase in a direction perpendicular to an interface between the cubic boron nitride grain and the binder phase using TEM-EDX, a first region having a carbon content larger than an average value of a carbon content of the binder phase exists, the interface exists in the first region, and a length of the first region is more than or equal to 0.1 nm and less than or equal to 10 nm.

Abstract: A cutting tool includes: a main body portion composed of a cemented carbide; and a front end portion composed of a binderless cubic boron nitride polycrystal, the front end portion being joined to the main body portion. In an axial direction along a rotation axis of the main body portion, the main body portion has a first end and a second end opposite to the first end. The front end portion has a neck portion and an edge portion, the neck portion protruding from the second end along the axial direction, the edge portion being continuous to the neck portion, the edge portion being located at a location distant away from the second end relative to the neck portion in the axial direction. In the axial direction, the neck portion has a third end on the edge portion side and a fourth end opposite to the third end.

Abstract: Provided is a cutting tool comprising a base body and a hard carbon film arranged on the base body, in which the hard carbon film includes an amorphous phase and a graphite phase, the degree of crystallinity of the hard carbon film is no more than 6.5%, and the degree of orientation of the graphite phase is no more than 6.

Abstract: A surface coated member having improved stability and a longer service life is provided. The surface coated member includes a base member and a hard coating formed on a surface thereof. The hard coating is constituted of one or more layers. At least one layer among the layers is a layer including hard particles. The hard particles include a multilayer structure having a first unit layer and a second unit layer being layered alternately. The first unit layer includes a first compound. The second unit layer includes a second compound. The first compound and the second compound are respectively made of one or more kind of element selected from the group consisting of a group 4 element, a group 5 element, a group 6 element of a periodic table, and Al, and one or more kind of element selected from the group consisting of B, C, N, and O.

Abstract: A cubic boron nitride sintered material includes: more than or equal to 50 volume % and less than 80 volume % of cubic boron nitride grains; and more than 20 volume % and less than or equal to 50 volume % of a binder phase, and when an oxygen content is measured in a direction perpendicular to an interface between cubic boron nitride grains using TEM-EDX, a first region having an oxygen content larger than an average value of an oxygen content of a cubic boron nitride grain exists, the interface exists in the first region, and a length of the first region along the direction perpendicular to the interface is more than or equal to 0.1 nm and less than or equal to 10 nm.

Abstract: A cutting tool includes a substrate; and a coating film, wherein the coating film includes a multilayer structure layer having first unit layer(s) and second unit layer(s), the first unit layer(s) and the second unit layer(s) are alternately layered, under a condition X-ray diffraction intensities of different planes in the multilayer structure layer are respectively represented by I(200), I(111), and I(220), the following formula 0.6?I(200)/{I(200)+I(111)+I(220)}, the first unit layer(s) has a NaCl-like structure in which an interplanar spacing d1c in a c-axis direction is larger than an interplanar spacing d1a in an a-axis direction, the second unit layer(s) has a NaCl-like structure in which an interplanar spacing d2c in the c-axis direction is smaller than an interplanar spacing d2a in the a-axis direction, and the following formulas are satisfied as well 1?d1a/d2a?1.02, 1.01?d1c/d2c?1.05, and d1a/d2a<d1c/d2c.

Abstract: A drill head includes a first attachment surface attached to a holder, a head tip surface opposite to the first attachment surface in an axial direction along the central axis, and a head outer peripheral surface continuous with the first attachment surface and the head tip surface. The head outer peripheral surface is provided with a first flute and a second flute extending helically about the central axis from the head tip surface to reach the first attachment surface. The first flute and the second flute are symmetric with respect to the central axis. Each of the first flute and the second flute has a first end and a second end that face each other with a space between them in a circumferential direction along a circumference centered on the central axis.

Abstract: A rotary cutting tool according to the present disclosure is rotatable about an axial line and includes a rake face and a flank face. The flank face is contiguous to the rake face. A ridgeline between the rake face and the flank face constitutes a cutting edge. In a cross section perpendicular to the axial line, the rake face is constituted of a plurality of straight line portions.

Abstract: A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.