A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced recuperator applications. This fully austenitic alloy is optimized for creep strength while allowing the formation of a chemically-stable external alumina scale at temperatures up to 900°C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. The first batch of commercially fabricated foil was produced with a composition selected from prior laboratory creep and oxidation results. The results for ∼80 and ∼105μm thick foil are compared to the prior laboratory-fabricated foils and other commercial candidates. Results from initial creep testing at 750°C show comparable creep strength to other commercial Fe-base foil candidates. Laboratory exposures in humid air at 650°–800°C have shown excellent oxidation resistance for this composition. Similar oxidation resistance was observed for sheet specimens of the first set of alloys exposed in a modified 65kW microturbine for up to 6,000h.

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