Method of applying an overcoat to a thermal barrier coating and coated article

摘要

An overcoat (20) is applied over thermal barrier coatings (18) such as YSZ or other columnar grain ceramic. The exposed surface of the TBC (18) is prepared to ensure that it is clean and has a proper roughness. The surface is then heated and an overcoat material such as a solid solution of chromia and alumina is deposited on the exposed surface, for example by plasma spraying to form a continuous overcoat on the TBC. The overcoat (20) is preferably corrosion and erosion resistant, and inhibits the migration of oxygen to the underlying TBC and alumina layer.