Preparation of an Aluminum Powder Composite with Double-Shell Nanostructure: Enhanced Thermal Conductivity Utilizing a Magnetic Orientation Effect

This article presents the design of a core–shell–shell nanostructured spherical aluminum powder (Al@PDA@POSS) through in-situ polymerization. The transient plane source method and infrared thermal imaging results demonstrate that the double-shell nanostructure can significantly enhance the compatibility of aluminum powder in an epoxy resin. Al@PDA@POSS was self-assembled with magnetic iron oxide to form a hybrid filler (Al@PDA@POSS-Fe3O4), resulting in magnetic properties. The hybrid fillers were precisely oriented in the resin matrix driven by magnetic force, constructing an effective thermal conduction path. Magnetic orientation plays a key role during the construction of a "thermal bridge". The directionally arranged filler composite (OA-Al@PDA@POSS-Fe3O4/EP) exhibits a thermal conductivity of 1.249 W/(m K) and an electrical conductivity of 5.56 × 10–10 S/cm at a load of 40 wt %. Compared to traditional composites, OA-Al@PDA@POSS-Fe3O4/EP composites not only possess high thermal conductivity and excellent insulation properties but also exhibit good thermal mechanical properties.