Microstructure and properties of graphene oxide reinforced copper-matrix composite foils fabricated by ultrasonic assisted electrodeposition

In this paper, graphene oxide (GO)/Cu composite (GO/Cu) foils with high thermal and mechanical properties were prepared by ultrasonic-assisted direct current electrodeposition. The effect of ultrasonic power and gra-phene concentration on the microstructure and properties of the composite foils was systematically investigated. It was found that the average grain size can be refined by both the addition of GO reinforcement and ultrasonic treatment. Under the optimized preparation condition with 120 W ultrasonic power and GO concentration of 0.8 g/L GO in plating solution, the average grain size was about 0.26 & mu;m and illustrated strong crystallographic orientation of (220). In addition, the GO content in the composites was increased from 0.67 wt% without ul-trasonic treatment to 1.72 wt%, and it was uniformly dispersed in the composite foil with ultrasonic effect. Compared with pure copper foil, the hardness value of the GO/Cu composite foil nearly doubled to 74.6 HV0.1, the average friction coefficient was decreased from 0.87 to 0.72 and the tensile strength of the composite foil was improved to 239 MPa with an elongation of 17%. Meanwhile, the thermal conductivity with optimized condition increased 39.8% to 556.57 W m-1 K-1. The improved mechanical and thermal properties of the GO/Cu com-posite foil were mainly ascribed to the grain refinement, change of preferred orientation and the presence of reduced GO reinforcement as a network in the composite foil.