There is an increased demand for sheets and foils of heat- and corrosion-resistant foils and sheets that can be used to manufacture compact heat-exchangers that withstand prolonged use at 700-750°C or above. Considerable progress has been made in characterizing materials ranging from 347 stainless steel, HR120 stainless alloy, and 625 Ni-based superalloy, to ODS alloys like PM2000 for microturbine recuperator applications. The welded primary surface (PS) or brazed plate and fin (PF) air cells used for recuperators for commercial microturbine or industrial turbine systems can also be used to make various heat-exchangers used in fuel-cell applications. If foils and sheets are made with grain size that is too fine, they can have very little creep-resistance relative to the same alloys used as plate or piping. Small amounts (2-5%) of water-vapor have been found to severely enhance oxidation attack of 347 steel foils after only about 1500 h at 650°C. ORNL data on a range of commercial alloys tested as foils indicate that much better oxidation resistance and creep resistance can be found in HR120 and alloy 625 at 650-750°C. This talk will overview recent work on additional alloys and address performance above 750°C.

Research was sponsored by the U.S. Department of Energy, Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Distributed Energy and Electricity Reliability, under contract DE-AC05-00R22725 with UT-Battelle, LLC.