Method for forming a multilayer thermal barrier coating

摘要

A method and apparatus for forming a multilayer thermal barrier coating such that the coating is composed of substantially homogeneous layers of different ceramic materials. The method entails supporting an article within a coating apparatus and in proximity to ceramic ingots of the different ceramic materials, and then simultaneously directing electron beams at both ingots so as to maintain a portion of each ingot in a molten state. According to a particular aspect of this invention, vapors of both ceramic materials coexist within the coating apparatus, yet each ceramic material is sequentially deposited onto the article by sequentially interrupting exposure of surfaces of the article to the vapors, such that the vapors form homogeneous successive layers on the surface. Exposure of the article to one or more of the vapors can be interrupted with a baffle, such that the vapor of only one of the ceramic ingots is directly deposited on a given surface of the article at any instant. The baffle can be employed in conjunction with the article being rotated at a constant or variable speed, and/or being translated above the members within the vessel to alter the relative thicknesses of the ceramic and an intermediate layer that is formed between adjacent layers and is composed of a mixture of the ceramic materials.