A cBN sintered body has 40%-85% cBN by volume and 15% to 60% binder phase by volume. and inevitable impurities. The binder phase has an Al compound including Al and at least one element selected from N, O and B, and a Zr compound including Zr and at least one element selected from C, N, O and B. The Zr compound includes ZrO, or ZrO and ZrO.sub.2. In an X-ray diffraction, where a peak intensity of a (111) plane of the ZrO is I.sub.1, a peak intensity of a (101) plane of tetragonal ZrO.sub.2 is I.sub.2t and a peak intensity of a (111) plane of cubic ZrO.sub.2 is I.sub.2c, a ratio of the intensity of I.sub.1 to total intensities of I.sub.1, I.sub.2t and I.sub.2c is 0.6-1.0, and an average grain size of the Al compound is 80 nm-300 nm.

A cBN sintered body has 40%-85% cBN by volume and 15% to 60% binder phase by volume. and inevitable impurities. The binder phase has an Al compound including Al and at least one element selected from N, O and B, and a Zr compound including Zr and at least one element selected from C, N, O and B. The Zr compound includes ZrO, or ZrO and ZrO.sub.2. In an X-ray diffraction, where a peak intensity of a (111) plane of the ZrO is I.sub.1, a peak intensity of a (101) plane of tetragonal ZrO.sub.2 is I.sub.2t and a peak intensity of a (111) plane of cubic ZrO.sub.2 is I.sub.2c, a ratio of the intensity of I.sub.1 to total intensities of I.sub.1, I.sub.2t and I.sub.2c is 0.6-1.0, and an average grain size of the Al compound is 80 nm-300 nm.

An article includes a substrate. The substrate includes at least two phases. The first phase includes a carbon-carbon (C/C) composite. The second phase includes a metal carbide. The second phase is disposed within a plurality of interconnected pores of the first phase, wherein the second phase extends from a surface of the substrate to a depth of at least 300 micrometers below the surface of the substrate.

An article includes a substrate. The substrate includes at least two phases. The first phase includes a carbon-carbon (C/C) composite. The second phase includes a metal carbide. The second phase is disposed within a plurality of interconnected pores of the first phase, wherein the second phase extends from a surface of the substrate to a depth of at least 300 micrometers below the surface of the substrate.

The surface-coated cBN sintered material includes a cBN sintered material containing cBN particles and a binder, and a coating. A proportion of the cBN particles in the cBN sintered material is 80 to 98% by volume, the binder contains a first compound including at least one element of Al and Cr and at least one element of N, B and O. The coating contains a layer A in contact with the cBN sintered material. The layer A is constituted of Al.sub.x1Cr.sub.y1M.sub.z1C.sub.a1Nb.sub.b1O.sub.c1 (provided that M is at least one element of Ti, V, Nb and Si, and 0.25x10.75, 0.25y10.75, 0z10.5, x1+y1+z1=1, 0a10.5, 0.5b11, 0c10.1, and a1+b1+c1=1 are satisfied).

The surface-coated cBN sintered material includes a cBN sintered material containing cBN particles and a binder, and a coating. A proportion of the cBN particles in the cBN sintered material is 80 to 98% by volume, the binder contains a first compound including at least one element of Al and Cr and at least one element of N, B and O. The coating contains a layer A in contact with the cBN sintered material. The layer A is constituted of Al.sub.x1Cr.sub.y1M.sub.z1C.sub.a1Nb.sub.b1O.sub.c1 (provided that M is at least one element of Ti, V, Nb and Si, and 0.25x10.75, 0.25y10.75, 0z10.5, x1+y1+z1=1, 0a10.5, 0.5b11, 0c10.1, and a1+b1+c1=1 are satisfied).

A part made from a composite material having a ceramic matrix and including a protection device, the protection including a coating layer having a gradual composition. The gradual-composition coating layer includes at least one silicon phase and one aluminium phase, the proportions of which change according to the height in the layer, with a first height in the gradual-composition coating layer corresponding to a silicon-free composition, and a second height corresponding to an aluminium-free composition. A method for producing such a protection, and to a device for carrying out the method, are disclosed.

A part made from a composite material having a ceramic matrix and including a protection device, the protection including a coating layer having a gradual composition. The gradual-composition coating layer includes at least one silicon phase and one aluminium phase, the proportions of which change according to the height in the layer, with a first height in the gradual-composition coating layer corresponding to a silicon-free composition, and a second height corresponding to an aluminium-free composition. A method for producing such a protection, and to a device for carrying out the method, are disclosed.

A cutting tool includes a base material and a coating formed on the base material. The base material is a sintered body containing 30 to 80% by volume of cubic boron nitride, and a binder. The surface in contact with the coating, of the base material, has a plurality of convex portions made of the cubic boron nitride and a plurality of concave portions made of the binder. A surface roughness Rsub of the surface in contact with the base material, is 0.1 to 0.4 m. A surface roughness Rsurf of an outermost surface of the coating is 0 to 0.15 m. A surface roughness Rasurf of the outermost surface of the coating is 0 to 0.1 m. The surface roughness Rsub of the surface in contact with the coating, of the base material, is greater than the surface roughness Rsurf of the outermost surface of the coating.

A cutting tool includes a base material and a coating formed on the base material. The base material is a sintered body containing 30 to 80% by volume of cubic boron nitride, and a binder. The surface in contact with the coating, of the base material, has a plurality of convex portions made of the cubic boron nitride and a plurality of concave portions made of the binder. A surface roughness Rsub of the surface in contact with the base material, is 0.1 to 0.4 m. A surface roughness Rsurf of an outermost surface of the coating is 0 to 0.15 m. A surface roughness Rasurf of the outermost surface of the coating is 0 to 0.1 m. The surface roughness Rsub of the surface in contact with the coating, of the base material, is greater than the surface roughness Rsurf of the outermost surface of the coating.