3D printing Si3N4 reinforced phase change composites with superior electrical insulation properties for thermal management

Effective thermal management materials are crucial for modern electronics, aerospace, and energy applications. This study investigates a novel approach by constructing a Si₃N₄ skeleton with a triply periodic minimal surface (TPMS) structure and reinforcing phase change materials (PCM) with boron nitride (BN) to develop Si₃N₄@BN/PCM composites that exhibit enhanced thermal conductivity, thermal stability and electrical insulation. Utilizing digital light processing 3D printing, a Si₃N₄ TPMS structure was prepared and subsequently reinforced with BN via vacuum-assisted infiltration into PCM. The incorporation of 3D Si₃N₄ skeleton and 2D BN flakes created a dual-scale network within the PCM, significantly increasing thermal conductivity from 0.24 W/m·K to 2.04 W/m·K. The presence of Si₃N₄ and BN notably improved thermal stability and reduced the coefficient of thermal expansion. Additionally, electrical insulation properties improved with an increase in volume resistivity and breakdown strength to 5.1 × 10 1 ⁴ Ω·cm and 62.4 kV/mm, respectively. This work demonstrates that Si₃N₄@BN/PCM composites effectively integrate high thermal conductivity, stability, and electrical insulation, thereby meeting the stringent demands of thermal management applications.