Although the specifications and performance of electrolytic copper foil vary from copper foil manufacturing enterprise to enterprise,the manufacturing process is basically the same.Using electrolytic copper or waste copper wire with the same purity as electrolytic copper as raw material,it is dissolved in sulfuric acid to produce an aqueous solution of copper sulfate.A metal roller is used as the cathode,and metal copper is continuously electrodeposited on the surface of the cathode roller through electrolytic reaction,while continuously peeling off from the cathode roller.This process is called foil electrolysis process.The last side peeled off from the cathode(smooth surface)is the side visible on the surface of the laminated board or printed circuit board,while the reverse side(commonly known as the matte surface)requires a series of surface treatments to bond with the resin in the printed circuit board.

Principle of electrolysis

During electrolysis,cations in the electrolyte migrate towards the cathode,and electrons are reduced at the anode.Anions run towards the anode,lose electrons,and are oxidized.Connect two electrodes to a copper sulfate solution and apply direct current At this point,it will be found that copper and hydrogen gas are evolving on the electrode plate connected to the power cathode.If it is a copper anode,both copper dissolution and oxygen evolution occur simultaneously.The reaction is as follows:

Cathode:Cu²+2e→2Cu

2H++2e→H2↑

Anode:4OH-+4e→2H2O+O2↑

2SO24+2H2O-4e→2H2SO4+O2↑

The copper dissolved from the anode supplements the consumption of copper ions in the electrolyte.By treating the surface of the cathode to a certain extent,the copper layer deposited on the cathode can be peeled off,resulting in a certain thickness of copper skin.Copper foil with certain functions is called copper foil.