Long-term operation of the solid oxide fuel cell (SOFC) depends strongly on reliability of its components. In the case of SOFCs incorporating Ni-ScCeSZ anodes, hydrogen reduction of NiO usually takes place during the first service cycle of operation or conditioning. Initial reduction causes changes in the chemistry, microstructure and properties of the Ni-ZrO₂ anode material, which in turn induce mechanical stresses in the cell.
The biaxial strength and elastic properties of unreduced (NiO–ScCeSZ) and reduced (Ni–ScCeSZ) anode were studied. Biaxial strength was determined by the biaxial flexure test ball-on-ball method at ambient temperature in air. Several specimens were tested in hydrogen atmosphere at 600 °C too. It was found considerable deterioration in mechanical behavior of Ni-ScCeSZ anodes after hydrogen reduction comparing to initial state. Biaxial strength of anode samples decrease from 100 MPa in air at ambient temperature to ~20 MPa after reduction in hydrogen atmosphere at 600 °C.
Additionally, in-plane biaxial strength was determined in hydrogen atmosphere at 600 °C using concentric ring-on-ring test. Displacement of the specimens under constant load and their electric conductivity during full testing time (up to 5 hours) were measured and recorded using PC analog-digital device. As a result compliance-time and conductivity-time dependences for the specimens were plotted as a function of their reduction in hydrogen.
Experimental results showed that respectively to changes in the chemical composition of Ni- ScCeSZ anode materials during reduction, the compliance of the anode specimens and their electric conductivity changes as well. It was found considerable deterioration in mechanical behavior of Ni- ScCeSZ anodes after hydrogen reduction comparing to initial state.

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