Microstructure and mechanical performance of Cu-SnO₂-rGO based composites prepared by plasma activated sintering

Abstract

A novel chemical technique combined with unique plasma activated sintering (PAS) was utilized to prepare consolidated copper matrix composites (CMCs) by adding Cu-SnO₂-rGO layered micro powders as reinforced fillers into Cu matrix. The repeating Cu-SnO₂-rGO structure was composed of inner dispersed reduced graphene oxide (rGO), SnO₂ as intermedia and outer Cu coating. SnO₂ was introduced to the surface of rGO sheets in order to prevent the graphene aggregation with SnO₂ serving as spacer and to provide enough active sites for subsequent Cu deposition. This process can guarantee rGO sheets to sufficiently disperse and Cu nanoparticles to tightly and uniformly anchor on each layer of rGO by means of the SnO₂ active sites as well as strictly control the reduction speed of Cu²⁺. The complete cover of Cu nanoparticles on rGO sheets thoroughly avoids direct contact among rGO layers. Hence, the repeating structure can simultaneously solve the wettability problem between rGO and Cu matrix as well as improve the bonding strength between rGO and Cu matrix at the well-bonded Cu-SnO₂-rGO interface. The isolated rGO can effectively hinder the glide of dislocation at Cu-rGO interface and support the applied loads. Finally, the compressive strength of CMCs was enhanced when the strengthening efficiency reached up to 41.