Effect of nanocrystallite structure on the lower activation energy for Sm2O3-doped ZrO2

Pure and 2 mol% Sm2O3-doped ZrO2 nanopowders were synthesized via the precipitation method. The very lower activation energy (,25.979 kJ/mol) related to the bulk counterpart is observed for the grain growth within the calcination temperature range of 600–1000 8C. Experimental results show that two factors were contributed to the lower activation energy of grain growth. Firstly, the introduction of oxygen vacancies in nano-2SmSZ grain surface reduces the activation energy of the formation of necks between grains. Secondly, the rotation process between coherent grains has very lower activation energy or even a zero-kinetic barrier. q 2004 Elsevier B.V. All rights reserved.