REDUCED THERMAL-DIFFUSIVITY OF NANOSTRUCTURED SILVER

The thermal diffusivity of nanostructured Ag, synthesized by inert-gas condensation and in situ compaction, was measured at room temperature by photoacoustic technique. The results indicated that the thermal di ffusivity of nanostructured Ag decreased catastrophically as compared to that of conventional polycrystalline Ag and ranged from about 27 to 74% that of polycrystalline Ag for all the nanostructured Ag specimen s investigated. Annealing experiments showed that although the thermal diffusivity of nanostructured Ag is related to its grain size, it is dependent strongly on annealing temperature. In addition, it was found that the variation of thermal diffusivity became weak as its relative density reached 93%, below which it decreased steeply with decrease o f specimen density. Preliminary analysis showed that the decrease of t hermal diffusivity originates mainly from its thermal conductivity, wh ich can be understood in terms of intense electron scattering within i nterfacial component.