Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, the oxidation protection system comprises a boron-glass layer formed on the composite substrate and a silicon-glass layer formed over the boron-glass layer. Each of the boron-glass layer and the silicon-glass layer include a glass former and a glass modifier.

An airfoil includes an airfoil wall that defines a leading end, a trailing end, and suction and pressure sides that join the leading end and the trailing end. The airfoil wall is formed of a silicon-containing ceramic. A first environmental barrier topcoat is disposed on the suction side of the airfoil wall, and a second, different environmental barrier topcoat is disposed on the pressure side of the airfoil wall. The first topcoat is vaporization-resistant and the second topcoat is resistant to calcium-magnesium-aluminosilicate.

An airfoil includes an airfoil wall that defines a leading end, a trailing end, and suction and pressure sides that join the leading end and the trailing end. The airfoil wall is formed of a silicon-containing ceramic. A first environmental barrier topcoat is disposed on the suction side of the airfoil wall, and a second, different environmental barrier topcoat is disposed on the pressure side of the airfoil wall. The first topcoat is vaporization-resistant and the second topcoat is resistant to calcium-magnesium-aluminosilicate.

Coated components and their methods of formation are provided. The coated component includes: a ceramic matrix composite substrate comprising silicon carbide and having a surface; a bond coat on the surface of the substrate; and an environmental barrier coating on the bond coat. The bond coat includes a plurality of discrete particles dispersed within a matrix phase that includes mullite. The plurality of discrete particles includes an oxygen getter and a transition metal oxide.

Coated components and their methods of formation are provided. The coated component includes: a ceramic matrix composite substrate comprising silicon carbide and having a surface; a bond coat on the surface of the substrate; and an environmental barrier coating on the bond coat. The bond coat includes a plurality of discrete particles dispersed within a matrix phase that includes mullite. The plurality of discrete particles includes an oxygen getter and a transition metal oxide.

A coating according to an exemplary embodiment of this disclosure, among other possible things includes a bond coat including gettering particles and diffusive particles dispersed in a matrix; a top coat disposed over the bond coat, the top coat includes metal silicate particles; and an intermediate layer between the bond coat and the top coat. The intermediate layer includes hafnium silicate particles and matrix. A concentration of metal silicate in the intermediate layer is less than a concentration of metal silicate in the top coat. An article is also disclosed.

A coating according to an exemplary embodiment of this disclosure, among other possible things includes a bond coat including gettering particles and diffusive particles dispersed in a matrix; a top coat disposed over the bond coat, the top coat includes metal silicate particles; and an intermediate layer between the bond coat and the top coat. The intermediate layer includes hafnium silicate particles and matrix. A concentration of metal silicate in the intermediate layer is less than a concentration of metal silicate in the top coat. An article is also disclosed.

A coating according to an exemplary embodiment of this disclosure, among other possible things includes a bond coat including gettering particles and diffusive particles dispersed in a matrix, a top coat disposed over the bond coat, and an intermediate layer between the bond coat and the top coat. The intermediate layer includes non-silicate oxide particles dispersed in a matrix. An article and a method of protecting a ceramic-based substrate are also disclosed.

A coating according to an exemplary embodiment of this disclosure, among other possible things includes a bond coat including gettering particles and diffusive particles dispersed in a matrix, a top coat disposed over the bond coat, and an intermediate layer between the bond coat and the top coat. The intermediate layer includes non-silicate oxide particles dispersed in a matrix. An article and a method of protecting a ceramic-based substrate are also disclosed.

A composition is provided that includes a silicon-containing material (e.g., a silicon metal and/or a silicide) and about 0.001% to about 85% of a Ga-containing compound, an In-containing compound, or a mixture thereof. The silicon-based layer can be a bond coating directly on the surface of the substrate. Alternatively or additionally, the silicon-based layer can be an outer layer defining a surface of the substrate, with an environmental barrier coating on the surface of the substrate. A coated component is also provided, as well as a method for coating a ceramic component. Gas turbine engines are also provided that include such a ceramic component.