A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

A part made of coated composite material, includes a substrate made of ceramic matrix composite material; a tie-coat layer covering the substrate; and a protective coating on the tie-coat layer and defining an environmental barrier, the protective coating including a rare-earth silicate and including a first outer region including an outer surface of the protective coating opposite to the substrate and having a first working creep, having deformation of less than or equal to 0.07% when a compressive stress of at least 50 MPa is applied for a duration of 10 hours at a temperature of between 1050 C. and 1300 C. The first region includes a grain growth inhibitor; and a second, inner, environmental barrier region, including an interface of the protective coating with the tie-coat layer and having a second working creep.

A part made of coated composite material, includes a substrate made of ceramic matrix composite material; a tie-coat layer covering the substrate; and a protective coating on the tie-coat layer and defining an environmental barrier, the protective coating including a rare-earth silicate and including a first outer region including an outer surface of the protective coating opposite to the substrate and having a first working creep, having deformation of less than or equal to 0.07% when a compressive stress of at least 50 MPa is applied for a duration of 10 hours at a temperature of between 1050 C. and 1300 C. The first region includes a grain growth inhibitor; and a second, inner, environmental barrier region, including an interface of the protective coating with the tie-coat layer and having a second working creep.

Environmental barrier coatings or coating systems that contain a bond coat, the bond coat containing an oxide matrix, and dispersed throughout the oxide matrix an oxidant gettering phase, a SiO.sub.2 based phase, that may be amorphous or crystalline, a crystalline phase, and an amorphous oxide phase, which is a self-healing phase having the ability to soften or melt and flow into cracks formed in the oxide matrix at predetermined temperatures that are below the melting temperature of the oxide matrix, where the amorphous oxide phase contains an alkaline earth alumino-silicate, and the crystalline phase contains Al.sub.6Si.sub.2O.sub.13, ZrSiO.sub.4, HfSiO.sub.4, Ca.sub.2ZrSi.sub.4O.sub.12, Ca.sub.2HfSi.sub.4O.sub.12, CaAl.sub.2Si.sub.2O.sub.8, CaSiO.sub.3, Al.sub.2TiO.sub.5, Mg.sub.2Al.sub.4Si.sub.5O.sub.18, BaAl.sub.2Si.sub.2O.sub.8, BaZrSi.sub.3O.sub.9, Y.sub.2Si.sub.2O.sub.7, Yb.sub.2Si.sub.2O.sub.7, and/or Al.sub.2O.sub.3, and methods for protecting ceramic matrix composite materials.

Environmental barrier coatings or coating systems that contain a bond coat, the bond coat containing an oxide matrix, and dispersed throughout the oxide matrix an oxidant gettering phase, a SiO.sub.2 based phase, that may be amorphous or crystalline, a crystalline phase, and an amorphous oxide phase, which is a self-healing phase having the ability to soften or melt and flow into cracks formed in the oxide matrix at predetermined temperatures that are below the melting temperature of the oxide matrix, where the amorphous oxide phase contains an alkaline earth alumino-silicate, and the crystalline phase contains Al.sub.6Si.sub.2O.sub.13, ZrSiO.sub.4, HfSiO.sub.4, Ca.sub.2ZrSi.sub.4O.sub.12, Ca.sub.2HfSi.sub.4O.sub.12, CaAl.sub.2Si.sub.2O.sub.8, CaSiO.sub.3, Al.sub.2TiO.sub.5, Mg.sub.2Al.sub.4Si.sub.5O.sub.18, BaAl.sub.2Si.sub.2O.sub.8, BaZrSi.sub.3O.sub.9, Y.sub.2Si.sub.2O.sub.7, Yb.sub.2Si.sub.2O.sub.7, and/or Al.sub.2O.sub.3, and methods for protecting ceramic matrix composite materials.

A method of forming a multilayer environmental barrier coating, comprising: providing a ceramic matrix composite; depositing a bond coat layer on the ceramic matrix composite; depositing a top coat layer on the bond coat layer; depositing an over coat layer on the top coat layer, wherein the over coat layer includes no more than approximately 50 percent by volume of porosity.