Abstract
Recently, a novel process was presented to fabricate dense yttrium-doped barium zirconate electrolyteswith high proton conductivity. This process was based on the use of a NiO additive during reactivesintering. We show here that materials made from this process present a fast degradation of mechanicalproperties when put in hydrogen-rich conditions, while material made from conventional sinteringwithout NiO aid remains intact in the same conditions. The fast degradation of samples made fromreactive sintering, leading to sample failure under highly compressive conditions, is due to the reductionof NiO nanoparticles at grain boundaries as shown from structural and chemical analyses using TransmissionElectron Microscopy. By the present study, we alert about the potential risk of cell failure due tothis mechanical degradation.