It has been reported that Sc2O3- doped ZrO2 has the highest ionic conductivity among zirconia ceramics. The xmol%Sc2O3 ñadded 3YSZ (abbr. xSc3Y; x = 0 to 8) powders were prepared by homogeneous precipitation reaction using urea. A mixture of cubic and tetragonal phases was observed in every xSc3Y sample by XRD, and the amount of cubic phase increased with increasing Sc2O3 content. The ionic conductivity of xSc3Y exhibited a maximum, 0.244 S/cm at x = 6. Although the fracture toughness of xSc3Y decreased with an increase in x, xSc3Y samples were tougher than 8YSZ. The improvement in fracture toughness is due to the fine microstructure compared to 8YSZ and the difference in fracture mode. Sc2O3 -added 3YSZ should be applicable as an electrolyte for high performance solid oxide fuel cells (SOFC) replacing 8YSZ.

Keywords: Yttria-zirconia, Scandia, Ionic conductivity, Fracture toughness, Solid oxide fuel cell