Activation energy and grain growth in nanocrystalline Y-TZP ceramics

Grain growth of nanocrystalline yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) was studied between 1250 and 1650 degrees C and compared to the Y-TZP data from the literature. All the results exhibited two distinctly different behaviour, where slow and fast grain growth regimes with activation energies similar to 280 and similar to 546 U mol(-1) prevail below and above similar to 1400 degrees C, respectively. Analysis of the data with respect to the grain growth mechanisms and the diffusion kinetics was in agreement with limited Y3+ lattice diffusion within the cubic zirconia nano-grains below similar to 1400 degrees C. This results in slow grain growth kinetics. Redistribution of Y3+ above similar to 1400 degrees C together with the equilibrium phase assemblage lead to enhanced grain boundary diffusion of Y3+ and results in enhanced grain growth of the sub-micrometer tetragonal grains. (C) 2007 Elsevier B.V. All rights reserved.