Diffusing Hf and Si Into Aluminide Bond Coats for TBCs

A process for making superior diffusion platinum-aluminide bond coats for plasma-sprayed or physical-vapor-deposited thermal-barrier coats (TBCs) on superalloy substrates has been devised. The novel aspect of the process lies in the use of several relatively inexpensive pack diffusion steps to incorporate hafnium and silicon to increase resistance to oxidation.