Abstract A synergistic inhibition study was carried out on an aluminium/copper galvanic coupling model in neutral aerated NaCl solution using scanning vibrating electrode technique (SVET). The approach allows the simulation of the local micro-galvanic cells of AA2024-T3 obtained from the potential difference between the intermetallic particles (IMPs) and the aluminium matrix. The inhibition effect of CeCl3 and 3-Amino-1,2,4-triazole-5-thiol (ATAT) was demonstrated by the reduction in the galvanic current density over Al and Cu surfaces. An improved inhibition from positive synergistic effect was revealed by the combination of the two inhibitors after 24 h of immersion, with the best inhibition recorded for Ce1.5ATAT3.5. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterize the Ce- and ATAT-based complex film formed and to illustrate the mechanism of inhibition.