The disclosure describes braze tape coatings and technique to form articles with differing physical properties in different layers or regions of the article. An example method includes forming a braze tape defining at least one layer that includes a first segment and a second segment. A portion of the second segment in the plane is adjacent to a portion of the first segment in a plane of the layer. The method also includes positioning the braze tape on a surface of a substrate, the plane of the layer of the braze tape being parallel to the surface of the substrate. The method also includes heating the braze tape to melt a constituent of at least one of the first coating material and the second coating material to form a densified coating on the surface of the substrate.

The disclosure describes braze tape coatings and technique to form articles with differing physical properties in different layers or regions of the article. An example method includes forming a braze tape defining at least one layer that includes a first segment and a second segment. A portion of the second segment in the plane is adjacent to a portion of the first segment in a plane of the layer. The method also includes positioning the braze tape on a surface of a substrate, the plane of the layer of the braze tape being parallel to the surface of the substrate. The method also includes heating the braze tape to melt a constituent of at least one of the first coating material and the second coating material to form a densified coating on the surface of the substrate.

The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 1010.sup.6 C.

The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 1010.sup.6 C.

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.

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.

The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 1010.sup.6 C..sup.1.

The present disclosure provides a method for coating a composite structure, comprising forming a first slurry by combining a first pre-slurry composition with a first carrier fluid, applying the first slurry on a surface of the composite structure, and heating the composite structure to a temperature sufficient to form a base layer on the composite structure. The first pre-slurry composition may comprise a first phosphate glass composition and a low coefficient of thermal expansion material, wherein the low coefficient of thermal expansion material is a material with a coefficient of thermal expansion of less than 1010.sup.6 C..sup.1.