Raising the Bar for Interconnect Protection by Lowering the Temperature
As developers look to enhance SOFC performance and extend stack life, the operating temperatures for SOFCs continues to drop. New cell manufacturing approaches, materials choices, and system designs are all focused on pushing high performance into the < 700°C range. As operating temperature drops, developers need protective coatings designed for these conditions, with even lower area-specific-resistance than common spinel solutions. While lower temperatures can slow oxidation and reduce chrome volatility, the effects of Cr poisoning are still important and detrimental to stack life. While inexpensive steels are attractive in lower temperature applications, they have limited corrosion resistance, and benefit from protective coatings.
Nexceris (fuelcellmaterials’ parent company) is leading the way in investigating new materials sets and coating processes that can create protective coatings designed for operating temperatures of 600°C. These new low temperature interconnect coatings will provide excellent electrical properties (we are developing both insulating or conducting variants) and protection against seal material attack, oxidation, and chrome loss that long-service life requires. Based on what we’ve learned providing coatings to date, we’ve identified ways to improve coating conductivity at low operating and production temperatures. We’re leveraging our experience with ChromLokTM and AlumiLokTM products to allow easy deposition and heat treatment options along with masking and co-firing options.
Early results suggest that these new coatings will provide excellent protection for an even wider range of SOFC systems, with operating temperatures from 600-900 °C. We are also particularly excited about the options these coatings could also provide for coating meshes, expanded foils and other complex shapes for current collection applications. Our new low temperature interconnect coatings are currently in the development stage and we anticipate beta trials with customers soon. If you are interested in learning more about our development work and the potential for next generation coatings in your SOFC system, drop us a line at info@fuelcellmaterials.com.