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 comparatively low‐temperature sintering at 1200–1300°C for 1 h were investigated. Zirconia ceramics having a uniform microstructure (grain size < 0.5 μm) stabilized with 6 mol% Sc2O3 showed high electrical conductivity (0.15 S/cm at 1000°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°C changed from 0.2 to 0.5 μm, 970 to 440 MPa, and 0.07 to >0.2 S/cm, respectively. Sc2O3‐doped zirconia polycrystals with high fracture strength and high electrical conductivity are promising candidates for the electrolyte material of solid oxide fuel cells.