Thermal stability and oxidation resistance of TiCrAlYO coatings on SS430 for solid oxide fuel cell interconnect applications

Chromia-forming ferritic stainless steels are being considered for interconnect applications in planar solid oxide fuel cell (SOFC) stacks because of their low cost and physical properties. At high temperatures, ferritic steels lack environmental stability in the SOFC operating environment, and gradually degrade the cell stack performance. In this study, an effective, dense and well adherent TiCrAlYO coating was deposited on an SS430 alloy using the filtered arc deposition technique. High-energy ion backscattering was used to characterize the composition and the thermal stability of the coatings. The chromium volatility of the coated steel plates at 800 °C was also measured using ion beam analysis. Significant reductions in oxidation rates as well as reduced Cr volatility were observed for the coated alloys.