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

Abstract 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 (Fe 3 O 4 ) nanospheres, and the amount of iron oxide deposited is easily controlled by modulating the precursors. Fe 3 O 4 -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.