A coated cutting tool includes a substrate of cemented carbide, cermet, ceramics, steel or cubic boron nitride and a multi-layered wear resistant coating. The multi-layered wear resistant coating has a total thickness from 5 to 25 μm and includes refractory coating layers deposited by chemical vapour deposition (CVD) or moderate temperature chemical vapour deposition (MT-CVD). The multi-layered wear resistant coating has at least one pair of layers (a) and (b), with layer (b) being deposited immediately on top of layer (a). Layer (a) is a layer of aluminium nitride having hexagonal crystal structure (h-AlN) and a thickness from 10 nm to 750 nm. Layer (b) is a layer of titanium aluminium nitride or titanium aluminium carbonitride represented by the general formula Ti.sub.1-xAl.sub.xC.sub.yN.sub.z with 0.4≤x≤0.95, 0≤y≤0.10 and 0.85≤z≤1.15, having a thickness from 0.5 μm to 15 μm, and at least 90% of the Ti.sub.1-xAl.sub.xC.sub.yN.sub.z of layer (b) has a face-centered cubic (fcc) crystal structure.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an α-Al.sub.2O.sub.3 layer containing a plurality of α-Al.sub.2O.sub.3 crystal grains. The α-Al.sub.2O.sub.3 layer includes a lower layer portion disposed at a side of the base material, an intermediate portion disposed on the lower layer portion, and an upper layer portion disposed on the intermediate portion. In a crystal orientation mapping performed on a polished cross-sectional surface of the α-Al.sub.2O.sub.3 layer using an EBSD, an area ratio of α-Al.sub.2O.sub.3 crystal grains with (001) orientation in the lower layer portion is less than 35%, an area ratio of α-Al.sub.2O.sub.3 crystal grains with (001) orientation in the intermediate portion is 35% or more, and an area ratio of α-Al.sub.2O.sub.3 crystal grains with (001) orientation in the upper layer portion is less than 35%.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an α-Al.sub.2O.sub.3 layer containing a plurality of α-Al.sub.2O.sub.3 crystal grains. The α-Al.sub.2O.sub.3 layer includes: a first region made up of an edge ridgeline, a region A of a rake face, and a region B of a flank face; a second region which is a region of the rake face except for the region A and covered with the coating; and a third region which is a region of the flank face except for the region B. The α-Al.sub.2O.sub.3 layer satisfies a relation b−a>0.5, where a is an average value of a TC(006) in the first region in texture coefficient TC(hkl) and b is an average value of the TC(006) in the second region or the third region in texture coefficient TC(hkl).

A surface coated cutting tool comprises a tool body. A TiAlCN layer having an average layer thickness of 2.0 to 20.0 μm and represented by (Ti.sub.(1-x)Al.sub.x)(C.sub.yN.sub.(1-y)) is provided on the surface of the tool body and has an average content ratio x.sub.avg of Al and an average content ratio y.sub.avg of C that satisfy 0.60≤x.sub.avg≤0.95 and 0.00≤y.sub.avg≤0.05, an area ratio occupied by crystal grains having an NaCl-type face-centered cubic structure that satisfies 90 area % or more, and crystal grains satisfying 0.01 μm<d≤0.20 μm in 10 to 40 area %. An average maximum length in a direction parallel to the surface of the tool body in each region in which the crystal grains having d of 0.01 μm<d≤0.20 μm are adjacent and connected to each other in the upper layer side region is 5.0 μm or less.

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 surface coated cutting tool comprises a base material and a coating layer that coats the base material, the coating layer including an alternate layer composed of a first unit layer and a second unit layer alternately stacked, the first unit layer being composed of a nitride containing aluminum and zirconium, in the first unit layer, when the total number of metal atoms constituting the first unit layer is represented as 1, a ratio thereto of the number of atoms of the zirconium being not less than 0.65 and not more than 0.95, the second unit layer being composed of a nitride containing titanium and silicon, in the second unit layer, when the total number of metal atoms constituting the second unit layer is represented as 1, a ratio thereto of the number of atoms of the silicon being larger than 0 and not more than 0.20.

A cutting tool including a rake face and a flank face includes: a substrate; and a coating film disposed on the substrate, wherein the coating film includes an Al.sub.2O.sub.3 layer, residual stress of the Al.sub.2O.sub.3 layer has a minimum value R.sub.min at at least a portion of a region d1 of the rake face, the minimum value R.sub.min is more than −0.27 GPa and less than or equal to −0.1 GPa.

A cutting tool including a rake face and a flank face includes: a substrate; and a coating film disposed on the substrate, wherein the coating film includes an Al.sub.2O.sub.3 layer, residual stress of the Al.sub.2O.sub.3 layer has a minimum value R.sub.min at at least a portion of a region f1 in the flank face, the minimum value R.sub.min is more than or equal to −0.25 GPa and less than or equal to −0.1 GPa.

A cutting tool includes a base material, and a coating film covering the base material in contact with the base material. The base material is a cubic boron nitride sintered material. The coating film is a ceramic. An amount of oxygen in the coating film is less than or equal to 0.040 mass percent.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises at least one α-type aluminum oxide layer; and, in the α-type aluminum oxide layer, a texture coefficient TC (0,0,12) of a (0,0,12) plane is from 4.0 or more to 8.4 or less, and a texture coefficient TC (0,1,8) of a (0,1,8) plane is from 0.5 or more to 3.0 or less.