FORMATION AND GROWTH OF BISMUTH NANODROPLETS EMBEDDED IN A Na 2 O-B 2 O 3 GLASS

The process of nucleation and growth of liquid Bi nanodroplets embedded in a soda-borate glass submitted to isothermal annealing at different temperatures was studied by small-angle x-ray scattering and transmission electron microscopy. The experimental results indicate that the formation and growth of Bi droplets occur in two successive stages after a short incubation period. The first is characteriz ed by the nucleation and growth of spherical droplets promoted by atomic diffusion and aggregation of isolated Bi atoms and the second one by a subsequent droplet coarsening. The experimental functions describing the time variation of the droplet average radius and density number at advanced stages of the growth process agree with the classical Lifshitz-Slyozov-Wagner (LSW) theory. However, the radius distribution was demonstrated to be well described by a lognormal function so differing from the prediction of LSW model.