Effect of Ni doping on the phase stability and conductivity of scandia-stabilized zirconia

The effect of Ni doping on the phase stability and conductivity of scandia-stabilized zirconia (SSZ) thick film was studied. A free-standing 10SSZ thick-film (10 mol% Sc₂O₃-stabilized zirconia, ~ 10 μm thick) that was previously in contact with a Ni layer during co-firing was fabricated. The 10SSZ thick-film showed a cubic phase in contrast to the rhombohedral phase shown for a bulk 10SSZ sample. The Ni content in the SSZ thick film was ~ 1.7 mol%. The effect of Ni on the cubic phase formation was also confirmed by the similar observation of the cubic phase in the Ni-doped bulk 10SSZ sample. The observed conductivity behavior also supported the XRD observation. Ni was found to hinder the transformation of the cubic phase to the rhombohedral on cooling in 10SSZ samples after a reduction treatment.