Regulation of Microstructure and Mechanical Properties of DC Electrodeposited Copper Foils by Electrolyte Parameters

Introducing nano-twins into electrolytic copper foil is an effective method to enhance strength and toughness. While pulse electrodeposition enables the easier preparation of high-density nano-twin copper, large-scale industrial production mainly relies on direct current electrodeposition. Therefore, systematically studying the effects of electroplating parameters on the microstructure and mechanical properties of direct current electrodeposited copper foil is crucial. In this paper, we discuss the effects of pH value, CCuSO4, and Jk on the microstructure and mechanical properties of electroplated copper foils at room temperature. The results show that copper foils exhibit stronger (220)Cu preferred orientation on the M surface than on the S surface with changes in pH value, CCuSO4, and Jk. When the pH value is 2.5, the CCuSO4 is between 70 and 90 g/L, and the Jk is within the range of 70–90 mA/cm2, the prepared copper foil has better compactness and no obvious pinhole-like defects. Particularly, the copper foil electroplated with a pH value of 2.5, a CCuSO4 of 80 g/L, and a Jk of 80 mA/cm2 consists of equiaxed and columnar grains, featuring small grain size, uniform distribution, and a dense structure, resulting in excellent mechanical properties.