Thermal Effusivity/Conductivity of Alumina Fillers

Abstract

Thermal effusivity and conductivity of sintered alumina filler at the micrometer-scale have been measured by a thermal microscope. Those of sintered alumina have also been measured for the purpose of comparison. The thermal effusivity ranged from 4.31 to 11.36 kJ·s^-0.5m^-2K^-1 and the calculated thermal conductivity varied from 6.2 W·m^-1K^-1 to 42.7 W·m^-1K^-1. This result indicates that alumina fillers have wide ranges of thermal conductivity at the micrometer-scale.
 On the other hand, the variation of thermal conductivity of alumina fillers was in good agreement with that of the sintered alumina. The maximum and minimum values of thermal conductivity of sintered alumina appeared at a dense and a porous area, respectively. On the basis of the data for sintered alumina, the variation of thermal conductivity of filler are greatly affected by the microstructure.