United Technologies Corporation

Brian J Shurman

Peter J Draghi

Peter Wrabel

Dale A Simard

Michael V Borruso

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 (,) having transpiration cooling passages (,), includes the step of diffusing an auxiliary coating (,) into an existing coating (,) and into the exposed substrate material (,) at the periphery of the passages to form a diffusion zone (,). The blade is then subjected to a stripping agent so that the diffusion zone (,) any undiffused existing coating, and any undiffused auxiliary coating are removed. The method causes a compensatory enlargement of the mouth (,) 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.

Apertured article preconditioned for recoating

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.

Method for preparing an apertured article to be recoated

A process for closing cooling holes of an airfoil includes the steps of providing an airfoil having a plurality of cooling holes, closing desired holes of said plurality of cooling holes by applying an ultraviolet curable material over the holes.

Process for precisely closing off cooling holes of an airfoil

A cleaning method for gas turbine engine airfoils includes a step of immersing an ultrasonic agitator, such as a welding horn, into a tank with a cleaning solution and a step of directing the ultrasonic agitator onto the portion of the airfoil having the crust layer. A subsequent step of high pressure water jet spray removes the crust debris. The cleaning method of the present invention significantly increases the power density of the ultrasonic cleaning.

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Plantsville, CT, United States of America

Brian J Shurman