Thermodynamics versus kinetics of grain growth control in nanocrystalline zirconia

This work presents a thorough analysis of the grain growth behavior of gadolinium doped yttria stabilized zirconia (YSZ). The effect of the dopant on the thermodynamics as well as on the kinetics of the process is reported by providing extensive experimental data. While normal grain growth following a parabolic growth relation was observed, gadolinium inhibited the process proportionally to its concentration. By using microcalorimetry, we showed that the dopant decreases the grain boundary energy of YSZ, and hence reduces the driving force for growth. Analysis of the growth profile at different temperatures and times indicate that gadolinium does not significantly affect the grain boundary mobility or the activation energy for grain growth. The results rationalize that the dopant is acting on a mostly thermodynamic basis and opens good perspective for design of coarsening control focused on the system energetics. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.