Abstract: A method of adjusting airflow through a plurality of cooling holes by depositing a thermal barrier coating on an exterior surface and/or an interior surface of the component by a physical vapor deposition process. The cooling holes are not masked. Thus, a portion of the thermal barrier coating partially obstructs airflow through the cooling holes and reduces airflow through the cooling holes. A predetermined pressure drop is developed across the cooling holes and airflow through the cooling holes is measured. The measured airflow is compared to a preselected range of desired cooling hole airflows and the steps of depositing the thermal barrier coating, developing the predetermined pressure drop, calculating airflow and comparing the measured airflow to the preselected range are repeated until the measured airflow is within the preselected range of desired cooling hole airflows.

Abstract: A method of removing metallic compositions, such as abradable rub coatings, environmental coatings, bond coats and braze alloys, from the surface of a cobalt-base substrate, such as turbine shrouds and vanes of gas turbine engines. The method is particularly suited for the removal of nickel-base braze alloys and aluminum-containing coatings, the latter of which includes abradable MCrAlY coatings and environmentally-protective diffusion aluminide coatings. The process generally entails contacting such metallic compositions with an aqueous solution containing hydrochloric acid and nitric acid and at a solution temperature of about 130.degree. F. to about 180.degree. F. The solution completely removes nickel-base alloys and aluminum-containing compositions from a cobalt-base substrate without removal or damage to the underlying substrate.