For developing a cyanide - free, environmentally friendly and low - cost rolled copper foil blackening process, 45.4～79.5 g/L Zn2+, 20.0～30.0 g/L sodium citrate, 30.0～50.0 g/L boric acid and 5.0～15.0 g/L ammonium sulfate were used as the basic bath components to form a light trapping structure on the surface of the rolled copper foil by adding additive A (surfactant) and additive B (inhibitor), so as to realize the blackening of cyanide - free electro - galvanizing. Moreover, the influences of bath composition and process parameters on the brightness (L*) of the coating were studied, and the electrical conductivity, roughness, high - temperature oxidation resistance and other properties of the blackened foil were tested. Results showed that the electrical conductivity of galvanized blackened foil was better than that of the nickel - plated blackened foil, and the brightness of zinc coating with a roughness (Rz) greater than 1.3 μm could meet the blackening requirements and as well as standards regarding low - profile copper foil. Furthermore, the galvanized blackened foil also met the high temperature oxidation resistance requirements.
