Chemical stability between NiO/8YSZ cermet and alkaline-earth metal substituted lanthanum chromite

The reaction between the separator in solid oxide fuel cells, alkaline-earth substituted lanthanum chromite (LaCr0.8Mg0.2O3,La0.8Ca0.2CrO3 and La0.8Sr0.2CrO3), and the fuel electrode, NiO8YSZ cernet, was investigated at high temperature. No chemical reaction was observed at the fuel electrode/separator interface of all samples annealed in a temperature range up to 1350°C. In the combination of fuel electrode and La0.8Sr0.2CrO3 annealed at 1400°C, no diffusion of specific elements was observed at the interface even for an annealing period of 12 h. In the case of the fuel electrode and La0.8Ca0.2CrO3, which was annealed at 1400°C, a dissolution of Ca into 8YSZ of the NiO/8YSZ cermet was observed at the NiO/8YSZ side of the interface. For the couple of the fuel electrode and LaCr0.9Mg0.1O3 treated at 1400°C, the Ni concentration increased and the Mg concentration decreased at the LaCr0.9Mg0.1O3 side of the interface. It was expected that a LaCr1−xNixO3 solid solution was formed by the replacement reaction of Mg by Ni.