Modification and repair of film cooling holes in gas turbine engine components

A method for modifying cooling holes in a gas turbine engine film-cooled component, said component comprising a) a body, b) said cooling holes, wherein said cooling holes have cooling hole walls extending from the interior of the body and terminating at cooling hole outlets proximate the external surface of the body, and c) a coating on the body extending to said cooling hole walls, said method for modifying said cooling holes comprising:

• removing said coating from the body;
• machining said cooling holes to remove material from said cooling hole walls, to enlarge said outlets, and to form tapers in the cooling holes extending from the outlets toward the interior of the body;
• and
• depositing a coating onto said body extending to said cooling hole walls.

A method for modifying cooling holes in a gas turbine engine Ni-based alloy film-cooled airfoil, the airfoil comprising a) an airfoil body, b) said cooling holes, wherein said cooling holes have cooling hole walls extending from the interior of the airfoil body and terminating at cooling hole outlets having original cooling airflow path widths of between about 0.012 inch (0.03 cm) and about 0.040 inch (0.1 cm) proximate the external surface of the airfoil body, c) an aluminide coating on the airfoil body extending to said cooling hole walls, and d) cracks in said cooling hole walls, said method for repairing said cooling holes comprising:

• acid etching said aluminide coating to remove said aluminide coating from the airfoil body
• machining said cooling hole outlets by a machining technique selected from the group of techniques comprising from electro-discharge machining, laser machining, and electro-stream machining to remove a portion of said cooling hole walls comprising said cracks thereby forming tapered segments in said cooling holes extending from said cooling hole outlets into said airfoil body and to enlarge said cooling hole outlet airflow path widths by from about one and one half to about two and one half times said original cooling hole outlet airflow path widths;
• and
• depositing an aluminide coating onto said airfoil body extending to said cooling hole walls by a vapor phase aluminide technique.