Increasing the thermal conductivity of boron nitride and aluminum nitride particle epoxy-matrix composites by particle surface treatments

The thermal conductivity of boron nitride and aluminum nitride particle epo xy-matrix composites was increased by up to 97% by surface treatment of the particles prior to composite fabrication. The increase in thermal conducti vity is due to decrease in the filler-matrix thermal contact resistance thr ough the improvement of the interface between matric and particles. Effecti ve treatments for BN involved acetone, acids (nitric and sulfuric) and sila ne. The most effective treatment involved silane such that the coating resu lted from the treatment amounted to 2.4% of the weight of the treated BN. T he effectiveness of a treatment was higher for a larger BN volume fraction. At 57 vol.% BN, the thermal conductivity reached 10.3 W/m.K. The treatment s had little effect on the specific surface area cf the BN particles. Silan e treatments were also effective for AlN. At 60 vol.% AlN, the thermal cond uctivity reached 11.0 W/m.K.