Gel-combustion, characterization and processing of porous Ni–YSZ cermet for anodes of solid oxide fuel cells (SOFCs)

The NiO–YSZ powder was prepared by the combustion of nitrate–glycine gel, a novel and versatile technique to form the nano-composite. The phase purity of the as-formed powder was confirmed by XRD. Onset sintering temperature was measured and sintering of NiO–YSZ specimens was carried out at 1450 °C for different soaking times. Porosity of the specimens decreases with increasing soaking time. Ni–YSZ cermet with varying open porosities between 23 and 41% was obtained by the in situ reduction of NiO–YSZ. Electrical conductivity, thermal expansion coefficient, and SEM microstructure of the Ni–YSZ specimens possessing varying porosities were evaluated. The electrical conductivity decreased while thermal expansion coefficient remained essentially the same with increasing porosity. SEM results confirmed the presence of interconnected open pores.