Copper foil, with its unique properties and versatile applications, is a promising candidate for catalytic conversion and energy utilization, with electrodeposition offering a strategic means to enhance its performance. Additives are crucial for optimizing copper foil properties but face challenges due to complex interfacial reactions and varying diffusion activation energies. Here, we focus on systematically investigating the individual effects of selected typical additives, including chloride ions (Cl ⁻ ), polyethylene glycol (PEG) and gelatin, to optimize the performance of copper foil. Compared to Cl ⁻ and PEG, gelatin more effectively improved the tensile strength and surface quality, and reduced the surface roughness of the copper foil at specific concentrations. Specifically, the samples prepared with the addition of gelatin (10 mg l ⁻¹ ) exhibit the best mechanical properties, achieving a tensile strength of 298 MPa and an elongation of 5.0% for the copper foils. The enhanced properties of the copper foil are attributed to the refinement of the grain structure, increased twin density, and reduced thickness of twin lamellae. The results are expected to provide guidelines to optimize copper foil properties through additive selection and concentration tuning, laying a foundation for enhancing nanomaterial performance in catalysis and energy utilization.

This study investigated the corrosion behavior of cold-drawn Cu-0.43 wt% Mg alloy wires, which were intended for high-speed railway contact lines, under varying temperature (30–50 °C) and relative humidity (85% and 93%) conditions in controlled humid heat environments. The corrosion resistance of the alloy wires after 48 h of humid heat testing was evaluated using electrochemical methods such as polarization curves and electrochemical impedance spectroscopy. The morphology and composition of the corrosion products were characterized using scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results demonstrated superior corrosion resistance for specimens exposed to higher temperature and lower humidity (50 °C, 85% RH), as evidenced by lower corrosion current densities and higher film/charge transfer resistances compared to lower temperature and higher humidity conditions (30 °C, 93% RH). This enhanced resistance correlated with the formation of denser, more continuous protective corrosion films observed under high-temperature and low-humidity conditions. Surface analyses confirmed that the corrosion films consisted primarily of copper oxides (Cu₂O and CuO), with only trace amounts of magnesium oxides detected, suggesting Mg played a minor role in the composition of the mature passive film under these conditions. These findings provide crucial data on the environmental degradation behavior of Cu-Mg contact wires, which is particularly relevant for applications in coastal or humid regions.

Joining high-strength, cold-drawn Cu-Mg alloy conductors is a critical challenge for ensuring the reliability of high-speed railway catenary systems. This study investigates the evolution of mechanical properties and microstructure in Cu-0.43 wt% Mg alloy wires joined by multi-pass butt-upset cold welding without special surface preparation. High-integrity joints were achieved, exhibiting a peak tensile strength of 624 MPa (~96% of the base material’s strength). After four upsetting processes, the tensile strength of the weld can reach 90% of the original strength, and the gains from subsequent upsetting processes are negligible. Microstructural analysis revealed the joining process is governed by localized severe shear deformation, which forges a distinct gradient microstructure. This includes a transition zone of fine, equiaxed-like grains formed by dynamic recrystallization/recovery, and a central zone featuring a nano-laminar structure, high dislocation density, and deformation twins. A multi-stage dynamic bonding mechanism is proposed. It progresses from initial contact via thin film theory to bond consolidation through a “mechanical self-cleaning” process, where extensive radial plastic flow effectively expels surface contaminants. This work clarifies the fundamental bonding principles for pre-strained, high-strength alloys under multi-pass cold welding, providing a scientific basis to optimize this heat-free joining technology for industrial applications.