High-temperature mechanical properties of reduced NiO–8YSZ anode-supported bi-layer SOFC structures in ambient air and reducing environments

Abstract This paper describes a study of the mechanical properties of the bi-layer half-cell structures of solid oxide fuel cells (SOFCs) at elevated temperatures in both ambient air and reducing environments. Half-cells with a thin, dense electrolyte layer of 8YSZ, supported by a thick, porous NiO–8YSZ anode precursor structure, were reduced in a gas mixture of 5% H 2 –95% Ar at 800 °C for selected time periods of up to 8 h. The development of the essential porous microstructure when forming the Ni–8YSZ anode cermet phase and its resulting effects on the equibiaxial strength, hardness and elastic properties of the half-cell structure were investigated in detail. Two sets of samples with different anode thicknesses were studied simultaneously to determine the effects of anode thickness on the SOFC structure's mechanical properties. The results were analyzed in relation to the porosity and composition of the samples.