A diamond sintered material includes diamond grains, wherein a content ratio of the diamond grains is more than or equal to 80 volume % and less than or equal to 99 volume % with respect to the diamond sintered material, an average grain size of the diamond grains is more than or equal to 0.1 μm and less than or equal to 50 μm, and a dislocation density of the diamond grains is more than or equal to 1.2×10.sup.16 m.sup.−2 and less than or equal to 5.4×10.sup.19 m.sup.−2.

A cutting tool including a base material and a hard layer provided on the base material, in which the hard layer is composed of a compound represented by Ti.sub.aAl.sub.bB.sub.cN, an atomic ratio a is 0.25 or more and less than 0.55, an atomic ratio b of is 0.45 or more and less than 0.75, an atomic ratio c of is more than 0 and 0.1 or less, a sum of the atomic ratio a, the atomic ratio b and the atomic ratio c is 1, a ratio I.sub.(200)/I.sub.(002) of an intensity I.sub.(200) of an X-ray diffraction peak of a (200) plane to an intensity I.sub.(002) of an X-ray diffraction peak of a (002) plane in the hard layer is 2 to 10, and a full width at half maximum of the X-ray diffraction peak of the (002) plane is 2 degrees to 8 degrees.

A coated cutting tool includes a substrate with a rake side, a clearance side and a cutting edge, and a coating including a first layer and a second layer. The second layer includes an inner layer and an outer layer, wherein the first layer is exposed through an opening in the inner layer and the opening extends over at least a portion of the width of the cutting edge. Thereby, a double layer is provided in critical areas, whereas a single layer is provided in other areas. Preferably, the double oxide layer includes aluminum oxide layers. A method for manufacturing the coated cutting tool is also provided.

The invention relates to α/β-sialon-based materials. The invention particularly relates to α/β-sialon-based materials that have an improved sintering activity and impart high edge strength to the sintered molded articles made of said materials.

A cutting tool includes: a base metal provided with a seat portion; a blade edge member that is a polycrystalline diamond sintered material containing polycrystalline diamond and a binder; and a brazing material that fixes the blade edge member to the seat portion of the base metal. The blade edge member has a thickness of greater than or equal to 0.3 mm. The brazing material is disposed between a blade edge bottom face of the blade edge member and the a seat bottom face of the seat portion and is in contact with the blade edge bottom face and the seat bottom face. The flank face is located outside of the base metal with respect to the lateral face of the base metal.

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 μm or more and 9 μm or less; the first layer is composed of Ti.sub.(1-x-y)Al.sub.xM.sub.yN, 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, x.sub.max, is 0.20 or more and 0.70 or less; a minimum value of x, x.sub.min, is 0 or more and 0.6 or less; x.sub.max and x.sub.min satisfy 0.01≤x.sub.max−x.sub.min≤0.7; a maximum value of y, y.sub.max, is 0.01 or more and 0.20 or less; a minimum value of y, y.sub.min, is 0 or more and 0.19 or less; and y.sub.max and y.sub.min satisfy 0.01≤y.sub.max−y.sub.min≤0.2.

A cutting tool comprising a base material and a coating arranged on the base material; wherein: the coating comprises an α-Al.sub.2O.sub.3 layer composed of a plurality of α-Al.sub.2O.sub.3 particles; the average particle diameter a of the α-Al.sub.2O.sub.3 particles in a first region of the α-Al.sub.2O.sub.3 layer is 0.10 μm or more and 0.30 μm or less; the average particle diameter b of the α-Al.sub.2O.sub.3 particles in a second region of the α-Al.sub.2O.sub.3 layer is 0.30 μm or more and 0.50 μm or less; the average particle diameter c of the α-Al.sub.2O.sub.3 particles in a third region of the α-Al.sub.2O.sub.3 layer is 0.30 μm or more and 0.50 μm or less; and the ratio b/a is 1.5 or more and 5.0 or less.

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 coated cutting tool has a substrate coated with a coating including a layer of α-Al2O3, wherein the α-Al2O3 layer exhibits a dielectric loss of 10−6≦tan δ≦0.0025, as measured with AC at 10 kHz, 100 mV at room temperature of 20° C.

A surface-coated cutting tool with a hard coating layer is provided. The hard coating layer includes at least a complex nitride or carbonitride layer (2) expressed by a composition formula: (Ti.sub.1-x-yAl.sub.xMe.sub.y)(C.sub.zN.sub.1-z), Me being an element selected from Si, Zr, B, V, and Cr. The average content ratio X.sub.avg, the average content ratio Y.sub.avg, and the average content ratio Z.sub.avg satisfy 0.60≦X.sub.avg, 0.005≦Y.sub.avg≦0.10, 0≦Z.sub.avg≦0.005, and 0.605≦x.sub.avg+y.sub.avg≦0.95. There are crystal grains having a cubic structure in the crystal grains constituting the complex nitride or carbonitride layer (2). A predetermined periodic content ratio change of Ti, Al and Me exists in the crystal grains having the cubic structure.

A cubic boron nitride-based sintered material includes cubic boron nitride particles of 70 to 95 vol %, in which in a structure of a cross-section of the sintered material, a binder phase with a width of 1 nm to 30 nm is present between the adjacent cubic boron nitride particles, the binder phase being made of a compound containing at least Al, B, and N and having a ratio of an oxygen content to an Al content of 0.1 or less in terms of atomic ratio.