The Effects of Current Density on Microstructure and Properties of Electrolytic Copper Foils

Under the condition of controlling the relevant electrolysis process parameters, 12μm-thick electrolytic copper foils were prepared by adjusting the electrodeposition time under different current densities. The surface morphology, mechanical properties and textures of the electrolytic copper foil at different current densities were studied using SEM, XRD, EBSD and universal testing machines. The fracture mechanism of the copper foil at different current densities was also analyzed in this paper. The results show that as the current density increases, the surface of the copper foil become larger and sharper. The main orientation of the crystal surface is {220}, and the preference firstly increases and then decreases. The high preference of the {220} crystal surface of the copper foil reduces its tensile strength. When the current density is from 8 to 14 A/dm 2 , the preferential degree of {111} decreases with the increase of current density, while the preferential degree of {220} increases, and the tensile strength of copper foil decreases. When the current density is from 14 to 26 A/dm 2 , the preferential degree of {111} and {311} increases with the increase of current density, while the preference of {220} crystal surface decreases, and the tensile strength of copper foil increases. The elongation of copper foil is affected by the fracture mechanism. When the current density is 8 A/dm 2 , the copper foil is plastically fractured and has high elongation. When the current density is 14A/dm 2 , the copper foil is brittle fracture and the elongation is low. When the current density is 26 A/dm 2 , the copper foil is plastically fractured but the effect of hydrogen evolution at high current density reduces the plasticity of the copper foil.