Experimental investigation of interfaces in graphene materials/copper composites from a new perspective

Copper matrix composites reinforced with three types of graphene materials, namely graphene nanoplatelets, nickel-plated GNPs and reduced graphene oxide, were separately fabricated using a molecular-level mixing process. Different from nanoparticles and nanofibers, graphene materials exhibit a unique two-dimension structure. The interface between graphene and the matrix could be divided into two types, namely graphene plane-Cu (Dp) and graphene edges-Cu (De). The interface microstructure between the constituent phases in graphene/Cu composites were observed for the first time from the two directions by means of transmission electron microscopy (TEM). TEM analysis results showed a big difference in interface microstructure and bonding mechanism in the three kinds of composites. The graphene materials were coherently bonded with the copper matrix in terms of mechanical, metallurgical or chemical bonding.