A coated tool includes a base and a coating film on the base. The coating film includes an Al.sub.2O.sub.3 layer, and a surface layer on the Al.sub.2O.sub.3 layer. The surface layer has a first erosion rate of 0.1 μm/min or less. The first erosion rate is obtained from measurement by causing a liquid A, in which 3 mass % of amorphous Al.sub.2O.sub.3 particles having a mean particle diameter of 1.1-1.3 μm is dispersed in purified water, to collide with the surface layer. The surface layer has a second erosion rate of 2.0 μm/min or more. The second erosion rate is obtained from measurement by causing a liquid B, in which 3 mass % of spherical Al.sub.2O.sub.3 particles having a mean particle diameter of 2.8-3.2 μm is dispersed in purified water, to collide with the surface layer.

A coated tool according to the present disclosure comprises a base body and a coating film. The base body contains a plurality of boron nitride particles. The coating film is located on the base body. In addition, in a case where a hardness is measured by pressing an indenter from a surface of the coating film to a depth of 20% of the coating film while changing an indentation load of the indenter, a maximum hardness difference, which is a difference between a maximum hardness and a minimum hardness of the hardness, is 4 GPa or more.

A coated cutting tool, comprising: a substrate; and a coating layer formed on a surface of the substrate, wherein the coating layer includes a lower layer and an upper layer in this order from a substrate side toward a surface side, and the upper layer is formed on a surface of the lower layer, the lower layer contains a compound having a composition represented by (Al.sub.xTi.sub.1-x)N, an average thickness of the lower layer is 1.0 μm or more and 15.0 μm or less, the upper layer contains an α-Al.sub.2O.sub.3 layer containing α-Al.sub.2O.sub.3, an average thickness of the upper layer is 0.5 μm or more and 15.0 μm or less, and in grains of the α-Al.sub.2O.sub.3 layer, a proportion of grains of which a grain size is 0.05 μm or more and less than 0.5 μm is 50% by area or more and 80% by area or less.

Provided is a surface-coated cutting tool including a complex carbonitride layer on the tool body, wherein a ratio of crystal grains having a NaCl type face-centered cubic structure is 80 area % or more, x.sub.avg and y.sub.avg satisfy 0.60≤x.sub.avg≤0.90 and 0.000≤y.sub.avg≤0.050, respectively, a composition of the Ti—Al complex carbonitride layer being represented by (Ti.sub.1-xAl.sub.x)(C.sub.yN.sub.1-y), the x.sub.avg being an average of x that is an Al content in a total content of Al and Ti, and the y.sub.avg being an average of y that is a C content in a total content of C and N, the crystal grains having the NaCl type face-centered cubic structure include crystal grains in which the x repeatedly increases and decreases, the crystal grains include 10 to 40 area % of crystal grains G.sub.1 having an average distance of 40 to 160 nm and crystal grains G.sub.s having an average distance of 1 to 7 nm.

A coated tool according to the present disclosure comprises a base body and a coating film. The base body contains a plurality of boron nitride particles. The coating film is located on the base body. Furthermore, the coating film includes a hard layer and a metal layer other than a simple substance of Ti, Zr, V, Cr, Ta, Nb, Hf, and Al located between the base body and the hard layer.

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/cm.sup.3 and no more than 3.5 g/cm.sup.3, 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.

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.

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 coated tool, such as a rotating, cutting tool, includes a tool body and a multilayer wear protection coating system. The wear protection system coats a functional surface of the tool body that is subject to wear and includes a first undoped diamond layer and a second undoped diamond layer disposed over the first undoped diamond layer. The first undoped diamond layer is electrically conductive and exhibits grain boundary conductivity from delocalized electrons. The second undoped diamond layer is electrically insulating. The first undoped diamond layer is 4-20 microns thick and is made with diamond grains whose size ranges from 4-10 nm. The first and second diamond layers are applied by chemical vapor deposition (CVD) using a hot-wire method. The wear protection system also includes an additional undoped diamond layer that is electrically insulating and is disposed between the functional surface of the tool body and the first diamond layer.