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.

An article including carbon-carbon composite substrate may be treated with an antioxidant coating prior to use in an oxidizing environment. The antioxidant coating may be configured to reduce oxidation at an external surface of the C-C composition and reduce ingress of oxidants into pores or other open passages defined by the C-C composite substrate to avoid internal oxidation. An example article includes a C-C composite substrate, a bond coat, and an antioxidant coating. The C-C composite substrate defines a friction surface and a non-friction surface. The bond coat is disposed on the non-friction surface. The antioxidant coating may be disposed on at least a portion of the bond coat. The antioxidant coating may include ytterbium disilicate and a sintering aid.

An article including carbon-carbon composite substrate may be treated with an antioxidant coating prior to use in an oxidizing environment. The antioxidant coating may be configured to reduce oxidation at an external surface of the C-C composition and reduce ingress of oxidants into pores or other open passages defined by the C-C composite substrate to avoid internal oxidation. An example article includes a C-C composite substrate, a bond coat, and an antioxidant coating. The C-C composite substrate defines a friction surface and a non-friction surface. The bond coat is disposed on the non-friction surface. The antioxidant coating may be disposed on at least a portion of the bond coat. The antioxidant coating may include ytterbium disilicate and a sintering aid.

High-entropy ultra-high temperature ceramics (HE-UHTC) coatings deposited on substrates, as well methods for depositing the HE-UHTC coatings on the substrates, are provided. An HE-UHTC electrode can be fabricated via spark plasma sintering (SPS) and then a thin coating of the HE-UHTC can be deposited in a precision-controlled manner on a substrate via an electro-spark deposition process.

High-entropy ultra-high temperature ceramics (HE-UHTC) coatings deposited on substrates, as well methods for depositing the HE-UHTC coatings on the substrates, are provided. An HE-UHTC electrode can be fabricated via spark plasma sintering (SPS) and then a thin coating of the HE-UHTC can be deposited in a precision-controlled manner on a substrate via an electro-spark deposition process.

A method of protecting a carbon-containing composite material part against oxidation, includes applying a first coating composition in the form of an aqueous suspension on an outside surface of the part, the first coating composition including a metallic phosphate; a powder of an ingredient comprising titanium; and a powder of B.sub.4C; subjecting the applied first coating composition to heat treatment in order to obtain a first coating on the outside surface of the part; applying a second coating composition on the first coating composition, the second coating composition including an aqueous suspension of colloidal silica; a powder of borosilicate glass; and a powder of TiB.sub.2; and subjecting the applied second coating composition to second heat treatment in order to obtain a second coating on the first coating.

A method of protecting a carbon-containing composite material part against oxidation, includes applying a first coating composition in the form of an aqueous suspension on an outside surface of the part, the first coating composition including a metallic phosphate; a powder of an ingredient comprising titanium; and a powder of B.sub.4C; subjecting the applied first coating composition to heat treatment in order to obtain a first coating on the outside surface of the part; applying a second coating composition on the first coating composition, the second coating composition including an aqueous suspension of colloidal silica; a powder of borosilicate glass; and a powder of TiB.sub.2; and subjecting the applied second coating composition to second heat treatment in order to obtain a second coating on the first coating.

A coated cutting tool, comprising: a substrate made of a cubic boron nitride-containing sintered body; and a coating layer formed on the substrate, wherein the cubic boron nitride-containing sintered body includes 65 volume % or more and 85 volume % or less of cubic boron nitride, and 15 volume % or more and 35 volume % or less of a binder phase; the cubic boron nitride is in a form of particles, the particles having an average particle size from 1.5 m or more to 4.0 m or less; the coating layer includes a lower layer, and an upper layer formed on the lower layer; the lower layer contains particles each having a composition represented by (Ti.sub.1-xAl.sub.x)N; the lower layer has an average thickness from 0.1 m or more to 1.0 m or less; the particles forming the lower layer have an average particle size from 0.01 m or more to 0.05 m or less; the upper layer contains particles each having a composition represented by (Ti.sub.1-yAl.sub.y)(C.sub.1-zN.sub.z); and the upper layer has an average thickness from 1.0 m or more to 5.0 m or less.

A coated cutting tool, comprising: a substrate made of a cubic boron nitride-containing sintered body; and a coating layer formed on the substrate, wherein the cubic boron nitride-containing sintered body includes 65 volume % or more and 85 volume % or less of cubic boron nitride, and 15 volume % or more and 35 volume % or less of a binder phase; the cubic boron nitride is in a form of particles, the particles having an average particle size from 1.5 m or more to 4.0 m or less; the coating layer includes a lower layer, and an upper layer formed on the lower layer; the lower layer contains particles each having a composition represented by (Ti.sub.1-xAl.sub.x)N; the lower layer has an average thickness from 0.1 m or more to 1.0 m or less; the particles forming the lower layer have an average particle size from 0.01 m or more to 0.05 m or less; the upper layer contains particles each having a composition represented by (Ti.sub.1-yAl.sub.y)(C.sub.1-zN.sub.z); and the upper layer has an average thickness from 1.0 m or more to 5.0 m or less.