Thermal Conductivity of Epoxy Composites Filled With Aluminium Nitride (AIN)

Abstract

Thermal conductivity of epoxy composites embedded with Aluminium Nitride(AlN) micro-fillers is estimated in the present thesis with analytical modelling. Thermal conductivity of AlN powder filled epoxy composite is calculated by measuring heat flow using an instrument Unitherm TM Model. In the analytical model,a mathematical model is developed to calculate the effective thermal conductivity of the composites filled with particulate fillers with different concentrations. The conductivity values measured experimentally are compared with the analytical ones and experimental ones. These composites with AlN have been fabricated and thermal conductivities of the samples are measured experimentally. Observations can be made that with 15 % of volume AlN in epoxy matrix, thermal conductivity has increased by about 6 times while with25 volume % the thermal conductivity has increased by about 59 times which is much higher than epoxy matrix. A conclusion to draw from the measured values are in close approximation with the proposed model close upto 25 % of vol. fraction at which a sudden rise is observed in the measured value of Keff. This sudden rise in effective thermal conductivity is due to the overlap between filler particle which leads to the formation of conductive chain. The volume percentage after which this phenomenon occur is termed as percolation threshold