The solid-state compatibility between calcium-doped lanthanum niobate and three perovskite cathode materials was investigated using two X-ray microbeam techniques, micro fluorescence absorption spectroscopy. powders (lanthanum strontium ferrite, either cobalt or copper-doped, cobaltite) in contact with the dense electrolyte pellet were annealed at 1150°C for 12–144 h to simulate effect of therm...