High-Thermal-Conductivity AlN Filler for Polymer/Ceramics Composites

To increase the thermal conductivity of polymer/ceramic composites, aluminum nitride (AlN) granules were added as a ceramic filler. Granules, sintered at 1850 degrees C for 24 h, showed a very high conductivity of 266 +/- 26 W (m.degrees C)(-1), as measured by a thermal microscope equipped with thermoreflectant and periodic heating techniques. This conductivity exceeds 80% of the theoretical value of AlN. Ceramic fillers consisting of the obtained AlN granules and commercially available hexagonal boron nitride particles (h-BN) powder plus polyimide resins were mixed and then molded at 100 MPa and 420 degrees C in a vacuum. The resultant composite showed a high conductivity of 9.3 W (m.degrees C)(-1). This study demonstrates that a high-thermal-conductivity filler effectively enhances the conductivity of polymer/ceramic composites.