Environmental barrier coating for a component and method for fabricating the same

An environmental barrier coating for a component comprising silicon having a first coefficient of thermal expansion, said environmental coating comprising:

• a silicon bondcoat bonded to at least a portion of an outer surface of said component;
• an inner intermediate layer bonded to said silicon bondcoat, said inner intermediate layer having a second coefficient of thermal expansion matched to said first coefficient of thermal expansion, said inner intermediate layer having a general composition of RE2Si2O7;
• an outer intermediate layer bonded to said inner intermediate layer and forming a plurality of microvoids;
• a protective layer bonded to said intermediate layer and having a general composition of RE2SiO5;
• and
• a surface layer bonded to said protective layer and comprising RE and having a ratio of RE to oxygen of at least 2:3, wherein said outer intermediate layer is infiltrated with said surface layer to form said protective layer on a surface forming each microvoid of said plurality of microvoids.

A component for a gas turbine engine, said component comprising:

• a substrate material comprising silicon, said substrate material having a first coefficient of thermal expansion;
• a silicon bondcoat bonded to at least a portion of an outer surface of said substrate material;
• at least one intermediate layer bonded to said silicon bondcoat and having a second coefficient of thermal expansion matched to said first coefficient of thermal expansion, the intermediate layer having a general composition of RE2Si2O7;
• a protective layer bonded to said intermediate layer and having a general composition of RE2SiO5;
• and
• a surface layer bonded to said protective layer and comprising RE and having a ratio of RE to oxygen of at least 2:3.

An environmental barrier coating for a component comprising silicon having a first coefficient of thermal expansion, said environmental coating comprising:

• a silicon bondcoat bonded to at least a portion of an outer surface of said component;
• an inner intermediate layer bonded to said silicon bondcoat, said inner intermediate layer having a second coefficient of thermal expansion matched to said first coefficient of thermal expansion, said inner intermediate layer having a general composition of RE2Si2O7;
• an outer intermediate layer bonded to said inner intermediate layer and forming a plurality of microvoids;
• a protective layer bonded to each microvoid, the protective layer having a general composition of RE2SiO5;
• and
• a surface layer bonded to said protective layer within each microvoid, the surface layer comprising RE and having a ratio of RE to oxygen of at least 2:3.