Excess Gibbs free energy and kinetics of grain growth of nanostructured silver

Samples of nanostructured silver were prepared by a mechanochemical technique and by electrodeposition. In the former, the microstructure was stabilized by intergranular cosegregation of Mg and O atoms. The excess Gibbs free energy of these samples was investigated by e.m.f. measurements at 453 K in a solid state electrochemical cell with AgI as a solid electrolyte. Electrodeposited pure silver samples had a labile microstructure even at 298 K. Their structural relaxation process was monitored in situ by chronopotentiometric measurements in an aqueous iodoargentate electrolyte. The time dependence of the e.m.f. could be quantitatively described by a parabolic law of grain growth without any adjustable parameter. Received: 13 January 2000 / Accepted: 8 February 2000