Apertured article preconditioned for recoating

摘要

A method for preparing a protectively coated, apertured article to be recoated reduces the likelihood that the apertures will become constricted as a consequence of subsequent recoating. The invention, described in the context of a gas turbine engine blade (12) having transpiration cooling passages (34), includes the step of diffusing an auxiliary coating (52) into an existing coating (28) and into the exposed substrate material (26) at the periphery of the passages to form a diffusion zone (54). The blade is then subjected to a stripping agent so that the diffusion zone (54) any undiffused existing coating, and any undiffused auxiliary coating are removed. The method causes a compensatory enlargement of the mouth (44) of each passage so that excess coating that accumulates in the passage mouths during subsequent recoating does not restrict the flow capacity of the passages.