Gas turbine component having location-dependent protective coatings thereon

A gas turbine component, comprising:

• a platform having a first coating on at least a portion of an underside thereof, wherein the first coating comprises a platform coating selected from the group consisting of a platform diffusion aluminide coating and a platform overlay coating;
• and
• an airfoil extending from the platform, the airfoil having an external surface and an internal surface defining cooling passages therethrough, the airfoil comprising
• an airfoil shape comprising a substrate alloy, the underside of the platform being remote from the airfoil shape,
• a second coating on the external surface of the airfoil shape, the second coating comprising an airfoil coating selected from the group consisting of an airfoil overlay coating and an airfoil diffusion aluminide coating, and
• a third coating on the internal surface of the airfoil shape, the third coating comprising an internal diffusion aluminide coating different in composition from the first coating.

A gas turbine component, comprising:

• a platform having a first coating on at least a portion thereof;
• and
• an airfoil extending from the platform, the airfoil having an external surface and an internal surface defining cooling passages therethrough, the airfoil comprising
• an airfoil shape comprising a substrate alloy,
• a second coating on the external surface of the airfoil shape, the second coating being different in composition from the first coating, and
• a third coating on the internal surface of the airfoil shape, the third coating being different in composition from the first coating.