High electrical conductivity and high fracture strength of Sc2O3-doped zirconia ceramics with submicrometer grains

The microstructure, crystal phase, electrical conductivity, and mechanical strength of less than 7-mol%-Sc2O3-doped zirconia ceramics fabricated by co mparatively low-temperature sintering at 1200-1300 degrees C for 1 h were i nvestigated. Zirconia ceramics having a uniform microstructure (grain size < 0.5 mu m) stabilized with 6 mol% Sc2O3 showed high electrical conductivit y (0.15 S/cm at 1000 degrees C) and high fracture strength (660 MPa), With the increase of Sc2O3, content from 3.5 to 7 mol%, the grain size, fracture strength, and electrical conductivity at 1000 degrees C changed from 0.2 t o 0.5 mu m, 970 to 440 MPa, and 0.07 to >0.2 S/cm, respectively. Sc2O3-dope d zirconia polycrystals with high fracture strength and high electrical con ductivity are promising candidates for the electrolyte material of solid ox ide fuel cells.