Combining Alumina Particles with Three-Dimensional Alumina Foam for High Thermally Conductive Epoxy Composites

Ceramic/polymer composite with a high thermal conductivity is a candidate of insulating materials for electronic packaging. However, traditional polymer composites filled with alumina (Al2O3) powders present limited enhancement in thermal conductivity even at a high loading due to thermal resistance on the filler/filler and filler/matrix interfaces. Herein, a contiguous 3D network of alumina foam (AF) filled with different diameters of Al2O3 microparticles via vacuum-assisted filtration proves to be a promising filler structure for thermal conductivity composites. The fabricated epoxy/AF/Al2O3 composite exhibits a high thermal conductivity of 4.1 W/mK and a significant thermal conductivity enhancement (TCE) of 2097%. Further study reveals a prominent synergistic effect between the 3D interconnected AF and Al2O3 microparticles, which plays a critical role in the formation of thermal percolation networks to promote thermal conductivity dramatically. Meanwhile, compared to previous reports, the composite resulted in a lower coefficient of thermal expansion (CTE) than those of most epoxy-based composites, showing great potential for heat conduction applications in microelectronics. This result paves an effective way of developing epoxy composites with high thermal conductivity in electronic packaging applications.

Automated summary

The epoxy/AF/Al2O3 composite with a high thermal conductivity of 4.1 W/mK and a significant thermal conductivity enhancement of 2097% demonstrates a promising filler structure for thermal conductivity composites. The synergistic effect between the 3D interconnected AF and Al2O3 microparticles plays a critical role in promoting thermal percolation networks and lowering the coefficient of thermal expansion compared to most epoxy-based composites.