Process for rejuvenating a diffusion aluminide coating

A process for rejuvenating a diffusion aluminide coating on a gas turbine engine component, the diffusion aluminide coating comprising an additive layer on a surface of the component and a diffusion zone below the additive layer and in a surface region of the component, the process comprising the steps of:

• removing the component from a gas turbine engine after the gas turbine engine was operated;
• aluminizing the component to form a rejuvenated diffusion aluminide coating having an additive layer with a thickness in excess of 100 micrometers;
• before placing the component in service on a gas turbine engine, treating the diffusion aluminide coating to an aqueous solution consisting essentially of nitric acid and phosphoric acid at a temperature of about 70° C. to about 80° C. for a duration of about 20 to about 30 minutes to remove at least part of the additive layer but the diffusion zone remains, thereby establishing a treated surface of the diffusion aluminide coating on the component;
• and then
• aluminizing the treated surface of the component to form a second rejuvenated diffusion aluminide coating having an additive layer with a thickness of not greater than 100 micrometers.