Effect of temperature on electrical and thermal conductivities of powder compacts: Ag-C and Ag-WC

The influence of temperature on electrical and thermal conductivities of two materials from powder metallurgy, Ag-C and Ag-WC, is studied. The increase in conductivities with heating temperature at constant density is showed. The need to consider temperature in addition to density in the conductivity models is highlighted. The coupled mechanisms, of densification and of bonding diffusion, which are at the beginning of the improvement of conductivities, are discussed. A new phenomenological model for electrical and thermal conductivities, taking into account these mechanisms and their interplay, is proposed. The model parameters are estimated. The model makes it possible to correctly predict the increases in conductivity of metal powders during manufacturing stages: cold compaction, annealing, free or load-assisted sintering.