An article for use in a high-temperature environment that includes a substrate including a superalloy material, a ceramic, or a ceramic matrix composite, and an abradable coating on the substrate, the abradable coating including a rare earth silicate and a dislocator phase, the dislocator phase forms one or more distinct phase regions in the abradable coating and comprises at least one of hafnium diboride (HfB.sub.2), zirconium diboride (ZrB.sub.2), tantalum nitride (TaN or Ta.sub.2N), tantalum carbide (Ta.sub.2C) titanium diboride (TiB.sub.2), zirconium carbide (ZrC), hafnium carbide (HfC), tantalum diboride (TaB.sub.2), hafnium nitride (HfN), or niobium carbide (NbC).

An article for use in a high-temperature environment that includes a substrate including a superalloy material, a ceramic, or a ceramic matrix composite, and an abradable coating on the substrate, the abradable coating including a rare earth silicate and a dislocator phase, the dislocator phase forms one or more distinct phase regions in the abradable coating and comprises at least one of hafnium diboride (HfB.sub.2), zirconium diboride (ZrB.sub.2), tantalum nitride (TaN or Ta.sub.2N), tantalum carbide (Ta.sub.2C) titanium diboride (TiB.sub.2), zirconium carbide (ZrC), hafnium carbide (HfC), tantalum diboride (TaB.sub.2), hafnium nitride (HfN), or niobium carbide (NbC).

An article may include a substrate including a ceramic matrix composite (CMC); a composite coating layer including a first coating material that includes a rare-earth disilicate and a second coating material that includes at least one of a rare-earth monosilicate, a CMAS-resistant material, or a high-temperature dislocating material, where the second coating material forms a substantially continuous phase in the composite coating layer.

An article may include a substrate including a ceramic matrix composite (CMC); a composite coating layer including a first coating material that includes a rare-earth disilicate and a second coating material that includes at least one of a rare-earth monosilicate, a CMAS-resistant material, or a high-temperature dislocating material, where the second coating material forms a substantially continuous phase in the composite coating layer.

An optical system includes a housing, an imaging device housed within the housing, and a window in the housing providing an optical path through the housing to the imaging device. The window includes a transparent substrate and a coating over the transparent substrate. The coating is made of an electrically conductive semiconductor. The imaging device is sensitive to and the coating is transparent to at least one of MWIR and/or LWIR wavelengths.

An optical system includes a housing, an imaging device housed within the housing, and a window in the housing providing an optical path through the housing to the imaging device. The window includes a transparent substrate and a coating over the transparent substrate. The coating is made of an electrically conductive semiconductor. The imaging device is sensitive to and the coating is transparent to at least one of MWIR and/or LWIR wavelengths.

A method of forming an impurity barrier layer on a CMC substrate may include introducing, to a heated plume of a thermal spray gun, a composite feedstock that includes a first coating material including a plurality of first particles; and a second coating material that may be different from the first coating material, where the second coating material at least partially encapsulates at least a portion of respective surfaces of the plurality of first particles; and directing, using the heated plume, at least the first coating material to a surface of a CMC substrate to deposit an impurity barrier layer including at least the first coating material.

A method of forming an impurity barrier layer on a CMC substrate may include introducing, to a heated plume of a thermal spray gun, a composite feedstock that includes a first coating material including a plurality of first particles; and a second coating material that may be different from the first coating material, where the second coating material at least partially encapsulates at least a portion of respective surfaces of the plurality of first particles; and directing, using the heated plume, at least the first coating material to a surface of a CMC substrate to deposit an impurity barrier layer including at least the first coating material.

In a method for repairing a coated article, the article has: a ceramic matrix composite (CMC) substrate; and a coating system having a plurality of layers. A damage site at least partially penetrates at least one of the layers. The method includes: applying a slurry of a repair material to the damage site for repairing a first of the penetrated layers; and after the applying, heating the repair material with a plasma torch.

In a method for repairing a coated article, the article has: a ceramic matrix composite (CMC) substrate; and a coating system having a plurality of layers. A damage site at least partially penetrates at least one of the layers. The method includes: applying a slurry of a repair material to the damage site for repairing a first of the penetrated layers; and after the applying, heating the repair material with a plasma torch.