This paper investigates the possible interaction between the alloying element Cu and trace element Pb in determining the surface microstructure and composition of model ternary AlPbCu alloys, to understand the role of Cu in reducing the anodic activation of Al caused by Pb in chloride solution. The surface microstructure and composition of model alloys AlPb, containing 20 ppm Pb, and AlPbCu, containing 0.5 Cu and 20 ppm Pb, were compared by use of scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, secondary-ion mass spectrometry and glow-discharge optical emission spectroscopy. For both alloys, a nanosized, nearly continuous, metallic Pb-rich film was formed at the oxide-metal interface during heat treatment, which is known to cause the activation of the binary AlPb alloy. The presence of Cu in solid solution with aluminum did not have any effect on the Pb segregation, and vice versa, Pb segregation did not have any effect on the uniform distribution of Cu. The analytical techniques used did not show co-segregation of Cu with Pb or any specific chemical or physical interaction between Pb and Cu near the metal-oxide interface, which could explain the passivating effect of Cu on Pb-containing aluminum alloys.