Soldering of copper using graphene-phosphoric acid gel

Abstract

Soldering is a physical process in which one metal melts and joins the other to form a strong bond, which further helps in electron conduction and increases the mechanical strength in any electronic circuits. The present work demonstrates the development of graphene-based flux comprising of 2 g of graphene and 2 ml of phosphoric acid for the residue-free, high stability, durable, and two-step soldering of copper wire on to the surface of the copper-based printed circuit board. The soldering flux can be applied to the copper, and wire can be soldered in ambient conditions using commercial soldering iron at a standard soldering temperature of 260℃. This flux helps the formation of strong and electrically conducting joints between the copper wire and copper-based printed circuit board. The joints are studied with scanning electron microscope images, and energy dispersive X-ray mapping successfully shows the formation of a joint between the copper wire and the copper and also shows the presence of graphene between the joint.