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.