MultiLayer Thermal-Environmental Barrier Coatings by Air Plasma Spraying for Next-Generation Turbine Engines

The global need for cleaner sources of energy production is rising, yet there are appreciable delays in bulk energy production by renewable sources (i.e., wind, solar, etc.). Consequentially, the power generation industry is in need of so-called ‘transitionary technologies’ to support the existing international grids whilst limiting the environmental impact. An example of this is the envisioned next-generation hydrogen-firing turbine engines.

The implicit operating conditions of these envisioned hydrogen-firing turbines requires additional considerations for protective surface coatings that have not yet been realized in the industry. Hot section components (i.e., turbine blades) in hydrogen turbines will require cost-effective, technologically robust surface solutions that address multiple degradation mechanisms simultaneously (thermomechanical excursions, water vapour volatilizatoin, etc.). For this, so-called thermal-environmental barrier coatings (T-EBCs) have been envisioned in the literature. This presentation will demonstrate the efficacy of plasma-spraying well-established zirconia-based oxides atop ytterbium disilicate (YbDS) EBCs to form all-plasma-sprayed T-EBC structures. Preliminary results suggest despite large thermal expansion mismatch strains, delamination does not occur during or after deposition of the dissimilar layers. The effect of thermal cycling on the adhesion of the discrete layers will also be shown.