Effective thermal conductivity of Cu/diamond composites containing connected particles

An analytical model for the thermal conductivity of Cu/diamond composites with connected particles is presented by replacement of a cluster of connected particles with an equivalent polycrystal subsequently using a multiple effective medium approach. By applying this model to the measured thermal conductivity of Cu/diamond composites prepared by high pressure high temperature sintering technique reported in the literature, we show that it quite well describes the observed thermal conductivity enhancement induced by the connected particles. We estimate the value of connected particle loading in real composites and show that large particles are easier to form the bonding contact than small particles. The present work also demonstrates that the sensitivity of thermal conductivity contribution from the connected particles strongly depends on the particle size, and their pronounced thermal conductivity enhancement should lie within the certain particle size range.