Brazing of metallic conductors onto ceramic plates in solid oxide fuel cells Part 1 Attaching a current collector

Furnace brazing to attach metallic plates to LaCrO₃ end plates in solid oxide fuel cell (SOFC) was investigated. The metallic plates act as a current collector to which a few conducting wires made of conventional heat-resisting alloys can be attached. The alloy CrFe5Y₂O₃1 was found to be a suitable material for the current collector because its thermal expansion coefficient matches that of LaCrO₃ better than heat-resisting nickel- or iron-based alloys. Among various filler alloys tested, SCP6 (Cu with 18 wt% Pd) enables the best wetting of LaCrO₃ and CrFe5Y₂O₃1 plates, leading to good adhesion between them. Several approaches were successfully pursued to reduce the bending of brazed LaCrO₃/SCP6/CrFe5Y₂O₃1 joints. The area specific resistance of some LaCrO₃/SCP6/CrFe5Y₂O₃1 joints increased slightly during annealing (1000°C in air for 2400 h) due to oxidation in the filler alloy. Nevertheless, it remained below the target limit of 0.2 · cm².