Thermally conducting composites for power electronics

The thermal conductivity of polyvinylchloride (PVC) containing graphite (Gr) micro fillers have been studied because of their potential applications in power electronics devices, batteries, electromagnetic shielding, antistatic and corrosion resistant coatings and other functional applications. Micro - composites containing (2, 4, 6, 8, 10, and 12%) volume fractions of graphite were fabricated. The thermal conductivity (K) of composites is enhanced by ~420% as concentration is increased from 0 to 12vol. %. Composites with a higher concentration show a stronger dependence in the thermal conductivity. It was revealed that, upon heating and cooling of these heterogeneous macro systems, hysteresis phenomena based on the effect of the “asymmetry” of the temperature evolution of the electrically active defects appear at the temperatures T<; 80°C. During the heating -cooling cycle, the relative changes in the ε' and tanδ with the temperature were about 33 and 61%, respectively.