Dual microstructure thermal barrier coating

Abstract

A multi-layer thermal barrier coating (12) having a porous first layer of ceramic insulating material (20) and a second relatively dense layer of ceramic insulating material (22) having a plurality generally vertical gaps (26) formed therein. The porous conventional as-deposited APS microstructure of the first layer provides thermal and chemical protection for the substrate, while the gaps of the columnar-grained second layer provide thermal shock resistance for the coating. An air plasma spray process may be used to deposit both the first and the second layers of material, as well as any underlying bond coat layer. The gaps of the columnar-grained second layer do not extend into the first layer. The pores (28) of the first layer function as crack-arrestors for cracks initiating at the gaps of the second layer.

Dependencies are inferred from the claim text.