A coating includes a first base layer including a nitride of at least Al and Cr, a second base layer including a nitride of at least Al and Cr overlying the first base layer, and an outermost indicator layer overlying the second base layer. The first base layer has a positive residual compressive stress gradient. The second base layer has substantially constant residual compressive stresses. The outermost indicator layer includes a nitride of Si and Me, wherein Me is at least one of Ti, Zr, Hf, and Cr. The outermost indicator layer has residual compressive stresses that are less than the residual compressive stresses of the second base layer.

A coated cutting tool including a substrate and a single layer or multi-layer hard material coating is provided. The substrate is selected from cemented carbide, cermet, ceramics, cubic boron nitride (cBN), polycrystalline diamond, steel or high-speed steel. The hard material coating includes at least one layer of gamma-Al.sub.2O.sub.3, exhibiting particularly high hardness and reduced Young's modulus. The gamma-Al.sub.2O.sub.3 layer of the coated cutting tool is obtainable by means of a reactive magnetron sputtering process using at least one Al target, wherein the deposition is carried out using a reaction gas composition of argon (Ar) and oxygen (O.sub.2) at a total reaction gas pressure within the range from at least 1 Pa to at most 5 Pa, at an O.sub.2 partial pressure within the range from 0.001 Pa to 0.1 Pa, and at a temperature within the range from 400° C. to 600° C.

In one aspect, refractory coatings are described herein having multiple cubic phases. In some embodiments, a coating comprises a refractory layer of TiAlN deposited by PVD adhered to the substrate, the refractory layer comprising a cubic TiAlN phase and a cubic A1N phase, wherein a ratio of intensity in the X-ray diffractogram (XRD) of a (200) reflection of the cubic AlN phase to intensity of a (200) reflection of the cubic TiAlN phase, I(200)/I(200), is at least 0.5.

An insert includes a cBN sintered compact including cBN particles and a binder phase binding the cBN particles. The cBN particles occupy 60% or more of the cross-sectional area of the cBN sintered compact. The binder phase contains Al compound particles containing at least one of AN or Al.sub.2O.sub.3. A particle distribution of the Al compound particles in a cumulative distribution based on the number of the Al compound particles in a cross section of the cBN sintered compact is as follows. The proportion of the Al compound particles with the particle diameter of 0.3 μm or larger is 5% or more, and the proportion of the Al compound particles with the particle diameter of 0.5 μm or larger is less than 5%.

The diamond-coated tool includes a base material and a diamond layer disposed on the base material, wherein the skewness Ssk defined in ISO25178 of the diamond layer is more than 0.

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.

The cutting insert may include a substrate including a first surface, a second surface, and a cutting edge. The substrate may include a hard phase and a binder phase, and the hard phase may include a first hard phase and a second hard phase. In X-ray diffraction analysis, a peak of the first hard phase may be observed on a higher angle side than a peak of the second hard phase. The second hard phase in the second surface may include a compressive residual stress of 150 MPa or more. A maximum height (Rz) in the second surface may be 0.2 to 1.5 μm. A maximum height of the cutting edge may be 2 to 30 times the maximum height in the second surface.

A coated tool of the present disclosure may include a base and a coating layer covering at least a part of the base. The base may include a hard phase of a carbonitride including Ti and a binder phase including at least one of Co and Ni and has a thermal expansion coefficient at 25 to 1000° C. of 9.0×10.sup.−6/° C. or more. The coating layer may include a TiCN layer and an Al.sub.2O.sub.3 layer positioned on the TiCN layer. The TiCN layer may have a compressive stress of 250 to 500 MPa. The Al.sub.2O.sub.3 layer may have a thickness of 2 μm or more and a compressive stress of 450 MPa or more, and the value of the compressive stress is greater than the compressive stress of the TiCN layer.

A cutting tool according to the present disclosure has a rake face, a flank face, and a cutting edge. The cutting edge is located between the rake face and the flank face. The cutting tool includes a substrate composed of a cubic boron nitride sintered material, and an oxide layer that covers the substrate and that constitutes at least part or whole of the rake face, the flank face, and the cutting edge. The oxide layer includes at least one element selected from a group consisting of titanium, aluminum, zirconium, and cobalt. A thickness of the oxide layer is 2 μm or less.

A method of producing a cubic boron nitride sintered material includes: forming an organic cubic boron nitride powder by attaching an organic substance onto a cubic boron nitride source material powder; preparing a powder mixture including more than or equal to 85 volume % and less than 100 volume % of the organic cubic boron nitride powder and a remainder of a binder source material powder by mixing the organic cubic boron nitride powder and the binder source material powder, the binder source material powder including WC, Co and Al; and obtaining the cubic boron nitride sintered material by sintering the powder mixture.