Effect of amounts and types of silicon nitride on thermal conductivity of Si₃N₄/epoxy resin composite

Abstract

Thermal conductive ceramic/resin composites are necessary for thermal management in order to improve the reliability of high-performance products in various industrial fields. The present study created composites consisting of silicon nitride (Si₃N₄) particles and epoxy resin by imbedding the particles into the resin matrix. Two common types of Si₃N₄ were applied in this work. α phase (α-Si₃N₄) and β phase (β-Si₃N₄) silicon nitride were loaded with epoxy resin. The effect of Si₃N₄ type on the thermal conductivity of composites was investigated by varying the Si₃N₄ particle content. For composites below 50 vol.% Si₃N₄, there was almost no difference in thermal conductivity between equivalently loaded α-Si₃N₄ or β-Si₃N₄/epoxy composites. However, for Si₃N₄ contents exceeding 50 vol.%, the β-Si₃N₄/epoxy composites showed higher thermal conductivities relative to the α-Si₃N₄/epoxy composite. The relative difference in thermal conductivities between the β-Si₃N₄ and α-Si₃N₄ epoxy composites (β-Si₃N₄/α-Si₃N₄) increased to 1.6 times at 68 vol.% of Si₃N₄ content.