Simultaneous enhancement of dispersion and interfacial adhesion in Al matrix composites reinforced with nanoceramic-decorated carbon nanotubes

Highlights: • Nanoceramic decoration was developed to simultaneously enhance CNT dispersion and CNT-Al interfacial adhesion. • Uniform, high-concentration CNT-Al₂O₃/Al powders were prepared. • Al₂O₃ nanoparticles acted as strong anchors at CNT-Al interfaces. • The composites exhibited enhanced mechanical property and superior electrical conductivity. Simultaneously achieving homogeneous dispersion and appropriate interfacial adhesion is the foremost concern for designing high-performance carbon nanotube (CNT)/Al matrix composites. Herein, a strategy for surface modification was developed to fabricate uniform CNT/Al composites with enhanced interfacial strength. Small quantities of Al₂O₃ nanoparticles were locally adhered to the surface of functionalized CNTs by electrostatic self-assembly, thereby promoting the adsorption of high concentrations of CNTs onto Al powders and hindering the agglomeration of CNTs. After densification, the CNTs retained their structural integrity and exhibited both individual distribution and unidirectional alignment in the matrix. As revealed by high-resolution transmission electron microscopy, the Al₂O₃ nanoparticles promoted a large elastic buckling of the nanotube inner wall and formed a curved, stable contact with the CNTs, producing strong anchors at the CNT-Al interface. Consequently, the CNT-Al₂O₃/Al composites exhibited enhanced mechanical properties compared with the CNT/Al composites, while maintaining superior electrical conductivity. This work demonstrates the great potential of surface decoration in producing advanced CNT/metal composites in electrical applications.