Sandvik Sanergy HT – A potential interconnect material for LaNbO4-based proton ceramic fuel cells

High temperature properties of Sandvik Sanergy HT have been studied to evaluate the alloy's suitability as an interconnect material for LaNbO4 based proton ceramic fuel cells (PCFCs). The thermal expansion behavior of the alloy deviates from LaNbO4 at higher temperatures which may be unfavorable, however the average values for the two materials over the whole temperature region are rather similar. The oxidation kinetics was parabolic and the rate constants were low at temperatures below 1000 °C. Accelerated oxidation was encountered after 300 h at 1000 °C revealing that the material may undergo severe degradation at sufficiently high temperatures. A complex oxide scale containing an inner layer of chromium oxide and an outer layer of various spinel phases containing chromium, manganese and iron was formed at all temperatures. As a consequence of high oxidation resistance and an oxide with relatively high electronic conductivity, the area specific resistance (ASR) of Sandvik Sanergy HT measured at 700 °C proved to be low.

► High temperature properties of Sandvik Sanergy HT.
► Parabolic oxidation behavior, accelerated oxidation encountered at 1000 °C.
► High oxidation resistance, formation of Cr2O3 and (Cr, Fe, Mn)3O4 spinel phases.
► Low area specific resistance due to formation of electrical conducting oxide scales.
► Sandvik Sanergy HT is considered a potential interconnect material for LaNbO4 PCFCs.