Growth kinetics of silver chloride precipitation in a Na2O-B2O3 glass investigated by means of small-angle X-ray scattering and transmission electron microscopy

The kinetics of silver chloride cluster formation in a sodium borate glass heat treated isothermally at different temperatures above the glass transition temperature has been studied with small-angle X-ray scattering (SAXS). It is established that the size distributions of particle number and particle volume have bimodal shapes, i.e. the system of AgCl droplets consists of two populations with significantly different mean radii. The bimodality of the size distribution functions is confirmed by results of transmission electron microscopy (TEM) even if different techniques of sample preparation are used. The resolution limits of the TEM techniques applied amount to 2 nm and are comparable with the smallest particle diameters detectable by the SAXS method. The evolution of the size distributions is discussed in the framework of the theories of nucleation, growth and Ostwald ripening.