Chemical compatibility and electrical contact between Ni–Cr–Mo alloy and LaCo0.6Ni0.4O3−δ in intermediate temperature solid oxide fuel cells

Abstract

The contact resistance and chemical compatibility of LaCo0.6Ni0.4O3−δ (LCN) coated Ni–Mo–Cr alloy are investigated at 750 °C in air for more than 530 h to simulate the contact situation of cathode/contact layer/interconnect in SOFC stacks. With La0.72Sr0.18MnO3 (LSM) as the cathode, the area specific resistance (ASR) of LSM/LCN/Ni–Mo–Cr alloy assembly increases to a maximum of 240 mΩ cm2 during the early stage of the test, and decreases after 55 h to a steady level of ∼220 mΩ cm2 till the end of the test. The contribution of formed oxide scale on the alloy to the measured ASR is negligible, compared to that of big AgLaMo2O8 particles sporadically distributed in LCN matrix. AgLaMo2O8 is formed of evaporated Mo from the alloy, Ag from the testing lead and La from the LCN before the oxide scale on the alloy is well developed. This reaction is expected to cease once the oxide scale is fully established.