Percolation transition in thermal conductivity of β-Si3N4 filled epoxy

Homemade beta-Si3N4 particles of different aspect ratio and commercial epoxy resin were used to form heterogeneous composites and a percolation transition was observed. The pre-percolation phase, near percolation phase and post-percolation phase were discussed with different models. In the near percolation phase, multicrystal model was taken to modify the percolation scaling law and provide physical images to the dumb proportional coefficient. X-ray holograph was used to compare the 3D morphology of the composites, and surface modification was found capable of enhancing the particle dispersion. The aspect ratio dependence was also discussed and the competition between the bridging effect and the interface thermal resistance was considered as the cause of the turning point in the thermal conductivity. (C) 2013 Elsevier Ltd. All rights reserved.