Microstructure and high thermal conductivity of Cu/CNTs-GO/Cu sandwich composite foils prepared by a novel electrodeposition-ultrasonic spraying and hot pressing sintering method

Abstract

High-efficiency heat dissipation is critical for maintaining optimal performance and reliability in high-power-density electronic devices. In this work, carbon nanotubes-graphene oxide (CNTs-GO) hybrid reinforced copper composite foils with macroscopic sandwich structure and microscopic interconnection are fabricated via a novel route combining ultrasonic precision spraying-electrodeposition and subsequent hot press sintering. The key processing parameters are optimized as follows: direct current electrodeposition at 8 A/dm²for 15 min; ultrasonic spraying with a nozzle power of 30 W, suspension feed rate of 0.1 mL/min with substrate temperature of 128 °C; vacuum hot-press sintering at 800 °C under a pressure of 10 kN (5.1 MPa) with a 60 min isothermal hold. Systematic characterization of the microstructure and thermal conduction mechanism reveals that when the CNT-GO concentration ratio is 2:1, the hybrid reinforcements form a continuous interpenetrating network. Additionally, in-situ generated Cu₂O nanoparticles at the Cu‑carbon interface could synergistically enhance interfacial bonding by forming covalent Cu-O-C bonds. These structural features collectively contribute to a maximum thermal conductivity of 619 W·m⁻¹·k⁻¹ in the composite foils, representing a 54.4% improvement over pure Cu (401 W·m⁻¹·k⁻¹). This exceptional performance is attributed to the designed sandwich Cu-C-Cu architecture with interconnected CuC substructure, as well as the microstructural refinement achieved through hot-press sintering.