Electroless plating of copper on carbon fiber surfaces and corresponding mechanism

Traditional methods for surface pretreatment of carbon fibers often rely on the use of precious metals like palladium and silver as activators to enhance surface reactivity through redox reactions, achieving metallization. However, such approaches are costly and economically inefficient. This study employed a cost-effective copper (Cu)-nickel (Ni) colloid mixture as an activator and investigated its effectiveness in enhancing surface reactivity. Meanwhile, it examined the influence of various parameters, such as pH value, reducing agent (formaldehyde (HCHO) concentration, temperature, and deposition duration, on the morphology and structure of copper-electrodeposited carbon fibers. To characterize the treated samples, scanning electron microscope (SEM) and x-ray photoelectron spectrometer (XPS) were adopted, shedding light on the mechanism underlying copper electrodeposition on the carbon fiber surface. The results indicate that Cu-Ni colloid mixture activation exhibits significant improvements. The optimal conditions for uniform and smooth copper electrodeposition on the carbon fiber surface identified as follows: a pH value of 13.5, a HCHO concentration of 15 ml L−1, a temperature of 50 °C, and a deposition duration of 5 min. Consequently, these results represent a cost-effective alternative to traditional precious metal-based activation methods, with promising applications in surface pretreatment for carbon fibers.