The diamond coated tool of the present invention is a diamond coated tool including a base material and a diamond layer coating a surface of the base material, and characterized in that the surface of the base material has an arithmetic average roughness Ra of not less than 0.1 m and not more than 10 m and an average length of roughness profile elements RSm of not less than 3.1 m and not more than 5.4 m, and that the diamond layer has a plurality of cavities at a portion bordering on the base material.

A surface-coated cutting tool includes a base material and a coating formed on a surface of the base material. The coating includes a first hard coating layer including crystal grains having a sodium chloride-type crystal structure. The crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of and a second layer composed of nitride or carbonitride of Al.sub.yTi.sub.1-y are stacked alternately into one or more layers. The first layer each has an atomic ratio x of Al varying in a range of 0.6 or more to less than 1. The second layer each has an atomic ratio y of Al varying in a range of 0.45 or more to less than 0.6. The largest value of difference between the atomic ratio x and the atomic ratio y is 0.05xy0.5.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one -type aluminum oxide layer, wherein, in the -type aluminum oxide layer, a texture coefficient TC (0,1,14) of a (0,1,14) plane is 1.4 or more.

[00001]$\begin{array}{cc}\mathrm{TC}\left(0,1,14\right)=\frac{I\left(0,1,14\right)}{I_0\left(0,1,14\right)}.Math.{\left\{\frac{1}{8}.Math..Math..Math.\frac{I\left(h,k,l\right)}{I_0\left(h,k,l\right)}\right\}}^{-1}& \left(1\right)\end{array}$

(In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the -type aluminum oxide layer, I.sub.0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for -type aluminum oxide, and (h,k,l) refers to eight crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (0,2,4), (1,1,6), (2,1,4) and (0,1,14).)

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one -type aluminum oxide layer, wherein, in the -type aluminum oxide layer, a texture coefficient TC (1,2,11) of a (1,2,11) plane is 1.4 or more.

[00001]$\begin{array}{cc}\mathrm{TC}\left(1,2,11\right)=\frac{I\left(1,2,11\right)}{I_0\left(1,2,11\right)}.Math.{\left\{\frac{1}{8}.Math..Math.\frac{I\left(h,k,l\right)}{I_0\left(h,k,l\right)}\right\}}^{-1}& \left(1\right)\end{array}$

(In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the -type aluminum oxide layer, I.sub.0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for -type aluminum oxide, and (h,k,l) refers to eight crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (0,2,4), (1,1,6), (2,1,4) and (1,2,11).)

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one -type aluminum oxide layer, wherein, in the -type aluminum oxide layer, a texture coefficient TC (1,0,16) of a (1,0,16) plane is 1.4 or more.

[00001]$\begin{array}{cc}\mathrm{TC}\left(1,0,16\right)=\frac{I\left(1,0,16\right)}{I_0\left(1,0,16\right)}.Math.{\left\{\frac{1}{8}.Math..Math.\frac{I\left(h,k,l\right)}{I_0\left(h,k,l\right)}\right\}}^{-1}& \left(1\right)\end{array}$

(In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the -type aluminum oxide layer, I.sub.0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for -type aluminum oxide, and (h,k,l) refers to eight crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (0,2,4), (1,1,6), (2,1,4) and (1,0,16).)

A surface coated cutting tool comprises: a tool substrate and a coating layer on a surface of the tool substrate; wherein the coating layer comprises a lower layer, an intermediate layer, and an upper layer, in sequence from the tool substrate toward the surface of the tool. The lower layer comprises an A layer having an average composition represented by formula: (Al.sub.1-xCr.sub.x)N, where x is 0.20 to 0.60; the intermediate layer comprises a B layer having an average composition represented by formula: (Al.sub.1-a-bCr.sub.aSi.sub.b)N, where a is 0.20 to 0.60 and b is 0.01 to 0.20; and the upper layer comprises a C layer having an average composition represented by formula: (Ti.sub.1--Si.sub.W.sub.)N where is 0.01 to 0.20 and is 0.01 to 0.10; and the upper layer has a repeated variation in W level with an average interval of 1 nm to 100 nm between adjacent local maxima and minima.

A coated tool include a first surface, a second surface which is adjacent to the first surface, and a cutting edge which is located on at least a portion of a ridge between the first surface and the second surface. The coated tool further includes a substrate, and a coating layer that is located on the substrate. The coating layer includes a titanium carbonitride layer and an aluminum oxide layer which has an -type crystalline structure. The titanium carbonitride layer is located nearer to the substrate than the aluminum oxide layer. When a value represented by the following equation is taken to be an orientation factor Tc(hkl) on the basis of peaks of the aluminum oxide layer analyzed by X-ray diffraction analysis, a ratio (Tcf(104)/Tcf(012)) of orientation factors Tcf(104) to Tcf(012) of the coating layer on the second surface is higher than a ratio (Tcr(104)/Tcr(012)) of orientation factors Tcr(104) and Tcr(012) of the coating layer on the first surface: Tc(hkl)={I(hkl)/I.sub.0(hkl)}/[(1/7){I(HKL)/I.sub.0 (HKL)}].

A cutting tool is a cutting tool comprising a substrate and a coating film disposed on the substrate, in which the coating film includes a first layer, the first layer is composed of an alternate layer where a first unit layer and a second unit layer are alternately stacked, the first unit layer is composed of Ti.sub.1-a-bAl.sub.aCe.sub.bN, a is 0.350 or more and 0.650 or less, b is 0.001 or more and 0.100 or less, the second unit layer is composed of Al.sub.cCr.sub.1-cN, c is 0.40 or more and 0.75 or less, and a and c satisfy a relationship of c>a.