Comparison between kinetic and thermodynamic effects on grain growth in nano-scale materials

A detailed comparison between kinetic and thermodynamic effects on grain growth in nanocrystalline Gd doped ceria ceramics was given. From the thermodynamic standpoint, the evolution of grain size with annealing time can be described using an analytical model for grain boundary segregation upon isothermal grain growth. From the kinetic standpoint, the single isothermal grain growth can be understood in terms of a single, thermally-activated rate process with constant grain boundary energy, σ_b. The solute excess in grain boundaries increases with grain growth and tends to its saturated value, therefore, the inhibition of grain growth can be attributed to the reduction of grain boundary energy σ_b through solute segregation.