An article may include a substrate and a coating system on the substrate. The coating system may include an environmental barrier coating (EBC) layer and a CMAS resistant layer on the EBC layer (e.g., as the top coat of the system). The CMAS layer includes a rare-earth (RE) monosilicate composition including a plurality of RE metal cations, wherein RE monosilicate composition is configured to react with CMAS to form a reaction product including a RE apatite phase with a RE.sub.2O.sub.3.SiO.sub.2 composition, wherein the RE of the RE.sub.2O.sub.3.SiO.sub.2 composition includes at least one of the plurality of RE metal cations of the RE monosilicate.

An article may include a substrate and a coating system on the substrate. The coating system may include an environmental barrier coating (EBC) layer and a CMAS resistant layer on the EBC layer (e.g., as the top coat of the system). The CMAS layer includes a rare-earth (RE) monosilicate composition including a plurality of RE metal cations, wherein RE monosilicate composition is configured to react with CMAS to form a reaction product including a RE apatite phase with a RE.sub.2O.sub.3.SiO.sub.2 composition, wherein the RE of the RE.sub.2O.sub.3.SiO.sub.2 composition includes at least one of the plurality of RE metal cations of the RE monosilicate.

The disclosure describes a method for forming a surface layer of a ceramic matrix composite (CMC) article. The technique includes depositing a slurry on a surface of an infiltrated CMC. The slurry includes a carrier material, a binder, a plasticizer, and solid particles. The solid particles include a plurality of fine ceramic particles defining a fine particle average size less than about 5 micrometers. The method further includes drying the slurry to form an article having an outer surface layer that includes the solid particles on the infiltrated CMC. The method further includes machining at least a portion of the outer surface layer of the article. The method further includes infiltrating the article with a molten infiltrant to form a composite article.

The disclosure describes a method for forming a surface layer of a ceramic matrix composite (CMC) article. The technique includes depositing a slurry on a surface of an infiltrated CMC. The slurry includes a carrier material, a binder, a plasticizer, and solid particles. The solid particles include a plurality of fine ceramic particles defining a fine particle average size less than about 5 micrometers. The method further includes drying the slurry to form an article having an outer surface layer that includes the solid particles on the infiltrated CMC. The method further includes machining at least a portion of the outer surface layer of the article. The method further includes infiltrating the article with a molten infiltrant to form a composite article.

The invention relates to a part made of silicon-based ceramic material or silicon-based ceramic matrix composite (CMC) material comprising an environmental barrier coating (EBC), said coating (12, 13) comprising a bonding layer (12) deposited on the surface of the ceramic material or ceramic matrix composite (CMC), said bonding layer (12) being topped by one or more layers together forming a multifunctional barrier structure (13), characterised in that the bonding layer (12) has at its interface with the multifunctional structure a polycrystalline silica layer (12) or sub-layer (12b).

The invention relates to a part made of silicon-based ceramic material or silicon-based ceramic matrix composite (CMC) material comprising an environmental barrier coating (EBC), said coating (12, 13) comprising a bonding layer (12) deposited on the surface of the ceramic material or ceramic matrix composite (CMC), said bonding layer (12) being topped by one or more layers together forming a multifunctional barrier structure (13), characterised in that the bonding layer (12) has at its interface with the multifunctional structure a polycrystalline silica layer (12) or sub-layer (12b).

Provided are a coated member in which damage of a coating film can be suppressed in a high temperature environment and the coating may be performed at low cost, and a method of manufacturing the same. A coated member includes a bond coat and a top coat sequentially laminated on a substrate made of a Si-based ceramic or a SiC fiber-reinforced SiC matrix composite, wherein the top coat includes a layer composed of a mixed phase of a (Y.sub.1-aLn.sub.1a).sub.2Si.sub.2O.sub.7 solid solution (here, Ln.sub.1 is any one of Nd, Sm, Eu, and Gd) and Y.sub.2SiO.sub.5 or a (Y.sub.1-bLn.sub.1′b).sub.2SiO.sub.5 solid solution (here, Ln.sub.1′ is any one of Nd, Sm, Eu, and Gd), or a mixed phase of a (Y.sub.1-cLn.sub.2c).sub.2Si.sub.2O.sub.7 solid solution (here, Ln.sub.2 is any one of Sc, Yb, and Lu) and Y.sub.2SiO.sub.5 or a (Y.sub.1-dLn.sub.2′d).sub.2SiO.sub.5 solid solution (here, Ln.sub.2′ is any one of Sc, Yb, and Lu).

Provided are a coated member in which damage of a coating film can be suppressed in a high temperature environment and the coating may be performed at low cost, and a method of manufacturing the same. A coated member includes a bond coat and a top coat sequentially laminated on a substrate made of a Si-based ceramic or a SiC fiber-reinforced SiC matrix composite, wherein the top coat includes a layer composed of a mixed phase of a (Y.sub.1-aLn.sub.1a).sub.2Si.sub.2O.sub.7 solid solution (here, Ln.sub.1 is any one of Nd, Sm, Eu, and Gd) and Y.sub.2SiO.sub.5 or a (Y.sub.1-bLn.sub.1′b).sub.2SiO.sub.5 solid solution (here, Ln.sub.1′ is any one of Nd, Sm, Eu, and Gd), or a mixed phase of a (Y.sub.1-cLn.sub.2c).sub.2Si.sub.2O.sub.7 solid solution (here, Ln.sub.2 is any one of Sc, Yb, and Lu) and Y.sub.2SiO.sub.5 or a (Y.sub.1-dLn.sub.2′d).sub.2SiO.sub.5 solid solution (here, Ln.sub.2′ is any one of Sc, Yb, and Lu).

Methods for forming a sintered patch on a silicon-based substrate are disclosed. The methods include applying a patch slurry on the silicon-based substrate, drying the patch slurry on the silicon-based substrate to form a dried patch material, and sintering the dried patch material in an oxidizing atmosphere to form a sintered patch on the silicon-based substrate. The patch slurry includes a patch material containing silicates in a fluid carrier.

Methods for forming a sintered patch on a silicon-based substrate are disclosed. The methods include applying a patch slurry on the silicon-based substrate, drying the patch slurry on the silicon-based substrate to form a dried patch material, and sintering the dried patch material in an oxidizing atmosphere to form a sintered patch on the silicon-based substrate. The patch slurry includes a patch material containing silicates in a fluid carrier.