Effect of reduced graphene oxides decorated by Ag and Ce on mechanical properties and electrical conductivity of copper matrix composites

摘要

This work investigated the influence of reduced graphene oxide (rGO) modified with silver (Ag) and cerium (Ce) on mechanical and electrical properties of copper matrix composites. Powders of Ce doped rGO and Ag doped rGO were synthesized using a hydrothermal reduction and an electroless plating (glucose chemical reduction) method, respectively. Then, composites with rGO content of 0.25 wt% were synthesized using ball milling and spark plasma sintering (SPS). The dispersion of the modified rGO and its bonding with the copper matrix have been signficantly improved. Hardness values of Ce-rGO/Cu and Ag-rGO/Cu composites were 26.3% and 16.4% higher than those of the sintered copper, and 19.4% and 10% higher than that of unmodified rGO/Cu composite. Meanwhile, the Ce-rGO/Cu and Ag-rGO/Cu composites maintained good conductivity and high ductility (with elongations of 26.3% and 25.2%, respectively). Compared with the sintered copper, the tensile strengths of these two types of copper matrix composites were 7.5% and 12% lower, respectively. The increase in hardness by using the modified rGOs is mainly due to the grain refinement of the matrix, and the lower value of the tensile strength is due to the defects of the modified rGOs and their poor bonding with the copper matrix.