Internal aluminization of coated substrates

A method for coating a component, the component comprising:

• a metallic substrate;
• a ceramic coating having one or more ceramic coating layers atop the substrate;
• and
• a cooling passageway system comprising a plurality of feed passageways extending from one or more inlet ports and a plurality of outlet passageways, the plurality of outlet passageways having openings in the coating,
• the method comprising:
• applying an aluminizing slurry to the plurality of outlet passageways;
• coupling the one or more inlets to a suction source;
• applying an external gas flow to the component, the suction source drawing gas from the external gas flow in through the outlet passageways and out through the one or more inlet ports, the external gas flow comprising at least 50% by volume combined one to all of Ar, He, and H2;
• and
• while the suction source is drawing the gas from the external gas flow, heating the component to aluminize the cooling passageway system.