Grain boundary mobility and grain growth behavior in polycrystals with faceted wet and dry boundaries

Microstructural changes in (K0.5Na0.5)NbO3 ceramics sintered in various atmospheres

“…In addition, recent work on KNN and BaTiO 3 has shown that the presence of a liquid phase can reduce the mobility of grain boundaries. 41,42 Therefore, we consider the decrease in the edge free energy ε of samples sintered in reducing atmospheres, as shown by roughening at the grain corners and edges, to be the cause of the change in grain growth behaviour.…”

Normal and Abnormal Grain Growths in BaTiO3 Fibers

“…The AGG mechanism of step‐growth‐controlled single phase system is phenomenologically analogous to the interface reaction mechanisms (2D nucleation) of a faceted solid‐liquid interface . The principle of microstructural evolution for solid–liquid two‐phase systems is applicable in studying the behavior of single phase system . For AGG by 2D nucleation mechanism, the growth rate, d r /d t , can be expressed as: where h is the height of 2D nuclei; A is the grain facet area, n 0 is the number density of atoms in the grain boundaries; n * is the number of atoms close to the nucleus; υ is the vibration frequency of atoms in the grain boundaries; ∆ E m is the activation energy for the atoms jumping across the interface; ∆ E 2D is the activation energy for 2D nucleation on a flat interface; k is the Boltzmann constant; and T is the absolute temperature.…”

Growth of single crystalline seeds into polycrystalline strontium titanate: Anisotropy of the mobility, intrinsic drag effects and kinetic shape of grain boundaries

“…Another possibility is given by the theory of nucleation barriers, which was mostly developed based on barium titanate [30][31][32][59][60][61][62]. The authors assume an energetic barrier (''nucleation barrier'') for facetted grain boundaries, which represents the energy needed to create a nucleus on a facetted boundary plane for moving the grain boundary.…”

“…Several effects are known to retard grain growth: pore drag [2,27,45,46], Zener pinning [3,[47][48][49][50], solute drag [2,51] and the existence of a critical driving force for grain growth (e.g. nucleation barriers [14,[30][31][32][52][53][54][55]). …”

“…Experiments in this geometry have been used for more than three decades in measuring growth rate anisotropy in ceramics, e.g. Alumina [22][23][24][25][26][27][28][29], Barium titanate [30][31][32][33] and Strontium titanate [34][35][36]. In some of these previous experiments and in this paper, measurements of the mean migration distance of different single crystal orientations into the polycrystalline matrix and of the matrix grain size as a function of time, temperature, and single crystal surface orientation are obtained.…”