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

摘要

An environmental barrier coating (10) for a component including silicon that has a first coefficient of thermal expansion is provided. The environmental coating includes a silicon bondcoat (30) that is bonded to at least a portion of an outer surface of the component. An intermediate layer (25, 27, 29) is bonded to the silicon bondcoat and has a second coefficient of thermal expansion matched to the first coefficient of thermal expansion. The intermediate layer has a general composition of RE 2 Si 2 O 7 . A protective layer (36) is bonded to the intermediate layer and has a general composition of RE 2 SiO 5 . A surface layer (38) is bonded to the protective layer. The surface layer includes RE and has a ratio of RE to oxygen of at least 2:3.