Synergistic effect of Zn electrodeposition and cerium conversion coating on the corrosion performance of low carbon steel

•Combined Zn-Ce-O double layer coating primers have been formed on low carbon steel.•A synergistic effect is established between the coating primer layers.•The coating primers are investigated by means of EIS, PDS, SEM, AFM, EDX and XPS.•The color characteristics, wettability, topology and composition are elucidated.•A conceptual model of the mechanism of the coating deposition process is proposed.