Densification below 1000 °C and grain growth behaviors of yttria doped ceria ceramics

Starting with nanopowders synthesized via carbonate coprecipitation, fully dense Ce1−xY xO2−δ (x=0.025–0.35) ceramics have been fabricated via pressureless sintering at a temperature as low as 950 °C. Y3+-doping retards both densification and grain growth, but its effect tends to saturate at ∼10 at.%. Sintering atmosphere was found in this work greatly affecting the grain growth during sintering, and a more oxidative one favors finer grain sizes. Grain growth of the yttrium-doped CeO2 ceramics obeys the parabolic law (normal growth) in the investigated temperature range 950–1400 °C, and its activation energy increases from 115.3 kJ/mol at 2.5 at.% of Y3+ to 293.2 kJ/mol at 35 at.% of Y3+.