Aluminized nickel-base, cobalt-base and nickel-cobalt-base heat resistant alloy substrates are provided in which, prior to aluminizing the substrate, the substrate is provided with a thin coating of rhodium and thereafter a thin coating of platinum, the coatings being diffusion bonded to the substrate, such that when the prepared substrate is aluminized by pack cementation, a compositely structured coating is obtained characterized by improved resistance to high temperature oxidation and sulfidation.
展开▼
