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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. [Copyright &y& Elsevier]

Abstract: LaCo0.6Ni0.4O3−δ (LCN64) was prepared through the polymeric steric entrapment precursor route with Polyvinyl alcohol (PVA) as the entrapment agent and was evaluated as a contact material between the metallic interconnect and the cathode in planar intermediate temperature solid oxide fuel cell stacks (IT-SOFC). The ratio of PVA to metal nitrates and the calcination temperature of the precursor were optimized for the process. The electrical conductivity and thermal expansion coefficient (TEC) of the synthesized LCN64 and its chemical compatibility with SUS 430 were also characterized. The results indicate that 1:4 is a proper ratio of PVA to metal nitrates for process control and safety management; and calcination of the precursor at temperatures above 650 °C leads to formation of single perovskite phase LCN64. The conductivity of fully sintered LCN64 is above 1150 S cm−1 in the temperature range between 100 °C and 800 °C, which is higher than those of conventional contact materials La1−x Sr x MnO3 (LSM) and LaNi y Fe1−y O3 (LNF). The average TEC is 17.22 × 10−6 K−1 at temperatures below 900 °C, which is higher than those of the metallic interconnect and cell components. Mn and Cr elements contained in SUS 430 migrated into the porous LCN64 layer at 800 °C without chemically forming resistive phases. [Copyright &y& Elsevier]