Thermal barrier coating system and coating methods for gas turbine engine shroud

摘要

A CMAS resistant coating system (24) and method for a gas turbine engine component includes a thermally insulating coating (12) having a dense vertically microcracked ceramic inner layer (18) and a columnar-grained ceramic top layer (20). The inner layer may be applied by an air plasma spray technique. The top layer may be deposited by a physical vapor deposition technique. In an exemplary coating, a ratio of the thickness of the top layer to the thickness of the inner layer is greater than 2 to 1. The layered coating may be particularly useful for the relatively thick coatings in gas turbine engine shroud applications.