Volume fraction dependence on coarsening of Y 2BaCuO 5 particles in Ba–Cu–O melt

Abstract

The effect of the volume fraction of the solid phase (Vf) on coarsening phenomena of Y 2BaCuO 5 (Y211) particles in Ba–Cu–O melt has been experimentally investigated. The rate constant of the coarsening cubic-law ( K) also depends strongly on Vf and is classified into two groups. The samples with Vf lower than 15% reveal higher coarsening rate constants than those with Vf higher than 20%. The coarsening properties of the lower Vf were in good agreement with the classical mean field (MF) model that considered the effect of Vf. It was clarified that K values of the higher Vf were suitable for those calculated numerically by the communicating neighbor (CN) model, in which the solute was assumed to diffuse directly among the particles. Thus, the coarsening phenomena of Y211 particles have been qualitatively explained by the difference in coarsening mechanisms as the MF and CN models.