Magnetic filler alignment of paramagnetic Fe3O4 coated SiC/epoxy composite for thermal conductivity improvement

We fabricated vertically aligned silicon carbide (SiC)/epoxy composites along the direction of heat transport using a magnetic field. SiC was made magnetically responsive by introduction of strong paramagnetic iron oxide (Fe3O4) nanospheres, and the amount of iron oxide deposited is easily controlled by modulating the precursors. Fe3O4-coated SiC filler was vertically aligned by an external magnetic field and generated particle columns. These columns act as a superior thermal conducting path. The thermal conductivity of the synthesized vertically aligned composite increased from 0.945 W m−1 K−1 to 1.681 W m−1 K−1 with 20 vol% filler loading that is a 1.78-fold increase compared with the randomly dispersed filler composite. Moreover, the electrical conductivity of SiC, which is a major drawback, was also controlled by the electrically insulating iron oxide coating. These results suggest promising applications of magnetically aligned SiC-based polymer composites in thermal interface materials.