Sintering behaviors of ag nanopowders with different particle sizes: A real-time synchrotron X-ray scattering study

We studied the sintering behaviors of Ag nanopowders with different particle sizes, by performing real-time synchrotron X-ray scattering experiments. The Ag nanopowder with a small particle size of 68 nm at room temperature exhibited a (defect free) crystal domain size of 4 nm. They consisted of one particle-one crystal domains. At low annealing temperatures, sintering occurred mainly through surface diffusion of Ag atoms near the surface. On the other hand, the Ag nanopowder with a large particle size of 566 nm at room temperature exhibited a crystal domain size of 49 nm. They consisted of one particle-multi crystal domains with grain boundaries. At higher annealing temperatures, sintering occurred mainly through volume diffusion of Ag atoms near the grain boundary. The results of the thermal analyses of the nanopowders were consistent with those of the synchrotron XRD and FE-SEM studies.