Synthesis and properties of Ni-YSZ cermet: anode material for solid oxide fuel cells

Nickel-yttria stabilized zirconia (Ni-YSZ) cermet with various vol.% of Ni has been prepared by the combustion of $Ni(NO_3)_2, Y(NO,)_3, ZrO(NO_3)_2$ and carbohydrazide followed by hydrogen reduction at 800°C, 2 h. The as-formed cermet powders were fine with surface area in the range of 27-32 $m^2/g$ with an average agglomerated particle size in the range of 0.25-0.8 $\mu m$. The samples could be sintered to the required density ( > 70% theoretical density) with porous microstructure. At lower Ni content ( < 30 vol.%) the conductivity increases with increasing temperature whereas at higher nickel content the cermets exhibit metallic behaviour. The thermal expansion of the cermets increases with increasing Ni content. The 30NJ-YSZ cermet with high electrical conductivity (40 S/cm) and low thermal expansion coefficient $(11.64X 10^{-6} K^{-1})$ appears to be compatible with the electrolyte (YSZ) for SOFC application