Investigations on the Diffusion of Platinum between CMSX-4 Superalloy and Platinum-Enriched Bond Coat

The depletion of Pt in Pt-enriched bond coats due to inter-diffusion with superalloys has been a critical concern for the long-term oxidation resistance thermal barrier coatings. This study investigated diffusion behaviour between CMSX-4 and two commercial comprising intermetallic ??/?-phase or ?-phase, aim understand mechanism that leads at high temperatures. results demonstrated superalloy disrupts its phase equilibrium, causes significant lattice parameter misfit ?-phase ??-phase, formation large ??-grains irregular shapes random orientations. In addition, by using Thermo-Calc software, was found have negative chemical interactions both Al Ta stabilise decreasing activity. growth Al2O3 scale during increases activity therefore accelerates inwards towards superalloys.