SOFC Protection Coatings Based on a Cost-Effective Aluminization Process

For solid oxide fuel cells the key barrier to technology commercialization is the high system cost, which is driven by materials selection. The use of steel components would be preferable but without protective coatings they are susceptible to oxidation and chromium volatilization in air and carburization and coking on the fuel side of the system. To enable the adoption of stainless steels low-cost protective coatings are required to enhance the high temperature corrosion properties. A low cost process to apply aluminide diffusion coatings to stainless steels is being developed, as an alternative to conventional aluminization processes to satisfy the corrosion resistance requirements of solid-oxide fuel-cell system developers as well as the broader power generation market. In Phase I the applicability of the coating approach for fuel cell applications was demonstrated through application- specific performance validation. Excellent high temperature oxidation, chromium volatilization, and coking resistances were demonstrated on a range of commercially important alloys. In parallel the manufacturability and value proposition of the technology was enhanced through scaling of the process to large balance-of-plant components with complex geometries. In the Phase II effort, the coating process will be further refined to target potential failure modes identified in the accelerated performance testing performed in Phase I. Critical process development in parallel with cost and manufacturing analyses to accelerate the commercialization of these coatings in concert with end-user evaluations. Commercial Applications and Other Benefits: Aluminide diffusion coatings have broad applicability outside of solid-oxide fuel cells in high-temperature industries such as power generation, coal gasification, natural gas processing, and chemical processing plants.