An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film is selected from a group consisting of an Er—Y composition, an Er—Al—Y composition, an Er—Y—Zr composition, and an Er—Al composition.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film is selected from a group consisting of an Er—Y composition, an Er—Al—Y composition, an Er—Y—Zr composition, and an Er—Al composition.

A method makes a silicon compound-based passivating coating on a ceramic matrix composite reinforced with carbon fibers. A piece made in a ceramic matrix composite reinforced with carbon fibers is placed in a closed chamber of an oven. A predefined load of solid silicon is placed in the chamber avoiding direct contact between the silicon and the piece. The oven is heated while maintaining inside the chamber predefined medium/low vacuum conditions, to generate silicon vapors inside the chamber. The vapors react with substances on the surface of the piece to form a surface coating having composites of the substances with the silicon. The partial pressure of the vacuum, temperature inside the chamber and exposure times of the piece to the silicon vapors to obtain a predefined thickness of the surface coating are chosen. The piece is cooled once the predefined thickness of the passivating coating is reached.

A method makes a silicon compound-based passivating coating on a ceramic matrix composite reinforced with carbon fibers. A piece made in a ceramic matrix composite reinforced with carbon fibers is placed in a closed chamber of an oven. A predefined load of solid silicon is placed in the chamber avoiding direct contact between the silicon and the piece. The oven is heated while maintaining inside the chamber predefined medium/low vacuum conditions, to generate silicon vapors inside the chamber. The vapors react with substances on the surface of the piece to form a surface coating having composites of the substances with the silicon. The partial pressure of the vacuum, temperature inside the chamber and exposure times of the piece to the silicon vapors to obtain a predefined thickness of the surface coating are chosen. The piece is cooled once the predefined thickness of the passivating coating is reached.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film consists essentially of 40 mol % to less than 100 mol % of Y.sub.2O.sub.3, over 0 mol % to 60 mol % of ZrO.sub.2, and 0 mol % to 9 mol % of Al.sub.2O.sub.3.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film consists essentially of 40 mol % to less than 100 mol % of Y.sub.2O.sub.3, over 0 mol % to 60 mol % of ZrO.sub.2, and 0 mol % to 9 mol % of Al.sub.2O.sub.3.

Environmental barrier coatings including a bondcoat layer including silicon and a rare earth silicate-based hermetic layer and rare earth silicate-based non-hermetic layer are provided. The rare earth silicate-based hermetic layer is deposited on the bondcoat via a thermal spray process and has an elastic modulus ranging from 100 GPa to 180 GPa. The at least one rare earth silicate-based non-hermetic layer is deposited on the rare earth silicate-based hermetic layer and has an elastic modulus ranging from 50 GPa to 100 GPa. Coated gas turbine engine components and methods for coating gas turbine engine components are also provided.

Silicon-carbon composite materials and related processes are disclosed that overcome the challenges for providing amorphous nano-sized silicon entrained within porous carbon. Compared to other, inferior materials and processes described in the prior art, the materials and processes disclosed herein find superior utility in various applications, including energy storage devices such as lithium ion batteries.

Silicon-carbon composite materials and related processes are disclosed that overcome the challenges for providing amorphous nano-sized silicon entrained within porous carbon. Compared to other, inferior materials and processes described in the prior art, the materials and processes disclosed herein find superior utility in various applications, including energy storage devices such as lithium ion batteries.

A method to produce a ceramic matrix composite with controlled surface characteristics includes: applying a scrim ply to a surface of a fiber preform, where the fiber preform includes silicon carbide fibers coated with boron nitride; infiltrating the fiber preform and the scrim ply with a slurry, thereby forming an impregnated ply on an impregnated fiber preform; infiltrating the impregnated fiber preform and the impregnated ply with a melt comprising silicon, and then cooling, thereby forming a ceramic matrix composite having a ceramic surface layer thereon, where the ceramic surface layer has a predetermined thickness and is devoid of boron; machining or grit blasting the ceramic surface layer to form an intermediate layer suitable for coating; and depositing an environmental barrier coating on the intermediate layer. Thus, a ceramic matrix composite coated with the environmental barrier coating is formed with the intermediate layer in between.