Thermal stability of laminated Ru-Al/Ru-Si-Zr coatings on Inconel 617

Abstract

The feasibility of using Ru-Si-Zr multilayer and laminated Ru-Al/Ru-Si-Zr multilayer coatings as bond coats of thermal barrier systems for Inconel 617 was investigated by annealing the coatings at 800 degrees C in ambient air. The multilayer coatings were fabricated through the deposition of a cyclical gradient concentration by using co-sputtering. The thermal stability of the annealed coatings was examined using X-ray diffraction, transmission electron microscopy, and Auger electron spectroscopy. The results indicated that Ru-Si-Zr multilayer coatings restricted the outward diffusion of metallic elements from Inconel 617 substrates, and an additional coating of an Ru-Al multilayer above the Ru-Si-Zr multilayer restricted the inward diffusion of oxygen from ambient air.