A sintered compact has a first material, a second material, and a third material. The first material is cubic boron nitride. The second material is a compound including zirconium. The third material is an aluminum oxide and the aluminum oxide includes a fine-particle aluminum oxide. The sintered compact has a first region in which not less than 5 volume % and not more than 50 volume % of the fine-particle aluminum oxide is dispersed in the second material. On arbitrary straight lines in the first region, an average value of continuous distances occupied by the fine-particle aluminum oxide is not more than 0.08 m and a standard deviation of the continuous distances occupied by the fine-particle aluminum oxide is not more than 0.1 m.

Cutting tool for machining by removal of matter from abrasive materials such as a material based on wood particles;

tool characterized in that it is composed of a mounting endowed with at least one machining element, and of which at least the machining edge is composed of a high-homogeneity oxide ceramic platelet composed of Al.sub.2O.sub.3 and ZrO.sub.2, with this platelet being obtained from: a homogeneous Al.sub.2O.sub.3XZrO mixture of Al.sub.2O.sub.3 nano-particles of average size smaller than 1 m, and ZrO.sub.2 nano-particles of tetragonal structure and average size smaller than that of the Al.sub.2O.sub.3 particles, with the ZrO.sub.2 content X being between 5 and 20% in mass of ZrO.sub.2 in relation to the total mass, with the mixture being formed into a plate via the gel-casting process followed by sintering or controlled cold isostatic compression, and with the plate (or platelets resulting from the division of the plate) being mechanically honed to produce the cutting edge.

A SiAlON composite includes a SiAlON phase including -SiAlON phase, -SiAlON phase and grain boundary phase. The SiAlON composite is prepared from a starting powder mixture including a silicon nitride powder and at least one powder providing aluminum, oxygen, nitrogen, yttrium (Y) and erbium (Er) to the SiAlON composite. The SiAlON composite contains the SiAlON phase of at least 90 vol %, z-value of the -SiAlON phase ranges between 0.27 and 0.36 and thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm.sup.2/sec) and equal to or less than 5.2 (mm.sup.2/sec).

A coated tool in the present disclosure includes a base and a coating layer located on a surface of the base. The coating layer includes a TiCN layer, an intermediate layer including Ti, and an Al.sub.2O.sub.3 layer in this order from a side of the base. The Al.sub.2O.sub.3 layer is located in contact with the intermediate layer at a position further away from the base than the intermediate layer. The intermediate layer includes a plurality of first protrusions protruding toward the Al.sub.2O.sub.3 layer. An average area of the plurality of first protrusions is 1700 nm.sup.2 or less. A cutting tool in the present disclosure includes a holder which is extended from a first end toward a second end and includes a pocket on a side of the first end, and the coated tool located in the pocket.

A sintered compact according to the present invention includes: a first material that is cubic boron nitride; a second material that is an oxide of zirconium; and a third material that is an oxide of aluminum, the second material including cubic ZrO.sub.2 and ZrO, the third material including -Al.sub.2O.sub.3, and the sintered compact satisfying the following relation:
0.9I.sub.zro2(111)/I.sub.al(110)30; and
0.3I.sub.zro(111)/I.sub.al(110)3, where I.sub.al(110), I.sub.zro2(111), and I.sub.zro(111) respectively represent X-ray diffraction intensities of a (110) plane of the -Al.sub.2O.sub.3, a (111) plane of the cubic ZrO.sub.2, and a (111) plane of the ZrO.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an -Al.sub.2O.sub.3 layer. The -Al.sub.2O.sub.3 layer contains -Al.sub.2O.sub.3 crystal grains and sulfur, and has a TC(006) of more than 5 in texture coefficient TC(hkl). The sulfur has a concentration distribution in which a concentration of the sulfur decreases in a direction away from a base-material-side surface of the -Al.sub.2O.sub.3 layer, in a thickness direction of the -Al.sub.2O.sub.3 layer.

A sintered compact according to the present invention includes: a first material that is cubic boron nitride; a second material that is an oxide of zirconium; and a third material that is an oxide of aluminum, the second material including cubic ZrO.sub.2 and ZrO, the third material including -Al.sub.2O.sub.3, and the sintered compact satisfying the following relation:

0.9I.sub.zro2(111)/I.sub.al(110)30; and

0.3I.sub.zro(111)/I.sub.al(110)3,

where I.sub.al(110), I.sub.zro2(111), and I.sub.zro(111) respectively represent X-ray diffraction intensities of a (110) plane of the -Al.sub.2O.sub.3, a (111) plane of the cubic ZrO.sub.2, and a (111) plane of the ZrO.

A sintered compact has a first material, a second material, and a third material. The first material is cubic boron nitride. The second material is a compound including zirconium. The third material is an aluminum oxide and the aluminum oxide includes a fine-particle aluminum oxide. The sintered compact has a first region in which not less than 5 volume % and not more than 50 volume % of the fine-particle aluminum oxide is dispersed in the second material. On arbitrary straight lines in the first region, an average value of continuous distances occupied by the fine-particle aluminum oxide is not more than 0.08 m and a standard deviation of the continuous distances occupied by the fine-particle aluminum oxide is not more than 0.1 m.

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.

In order to achieve a long service life for a machining tool, in particular for a solid carbide drill, it is provided with a special wear protection coating. In a first method step, in order to form this coating, a first layer made of a first material is applied in the region of a cutting edge and in the adjoining surface regions, and specifically, a flank face and a rake face. In a second step, the applied first material of the first layer is selectively removed at least partially, and preferably completely, only in the region of the cutting edge. Finally, in a third method step, a second layer made of a second wear-resistant material is applied both to the cutting edge and to the face regions. In this way, a coating having a high overall thickness in the face regions is made possible, without the risk of cracking.