Thermal conductivity of electric molding composites filled with β-Si₃N₄

New electric molding composites were fabricated with hybridizing epoxy and β-Si₃N₄ instead of silica. The thermal conductivity of composites filled with β-Si₃N₄ was compared with that co-filled with β-Si₃N₄ and SiO₂ The results demonstrate that the thermal conductivity of the composite increases obviously with the increasing of β-Si₃N₄ content. Thermal conductivity of β-Si₃N₄-filled composite is about 3.8 times as large as that of Si02-filled one when the additional volume fraction achieves to 50%. Based on the experimental results, the discussion of calculating model for predicting thermal conductivity of composites shows that Agari model is more applicable to predict the thermal conductivities of β-Si₃N₄ filled and β-Si₃N₄/SiO₂ co-filled composites. Furthermore, a common expression of Agari model for co-filled composites and its parameters are given.