The influence of cerium ion concentrations on the characteristics of hybrid films obtained on AA2024-T3 aluminum alloy

摘要

This work aimed to study the corrosion behavior of AA2024-T3 aluminum alloy substrates pre-treated with 3 glicidoxypropyltrimethoxysilane (GPTMS) silane layers doped with different cerium ion concentrations. The withdrawal speed of substrates from the sol was 20 cm • min-1. The hybrid films were obtained by dip-coating process and analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy, Rutherford scattering spectroscopy (RBS), salt spray test, and electrochemical analyses. The correlation among the results obtained from different analyses was very good and indicated that the addition of Ce ion in the hybrid coating contributed to the corrosion resistance; however, for the high Ce ion concentration, the barrier effect of the hybrid films was deteriorated. The results obtained by RBS showed that the concentration of Ce ion in the hybrid film increased linearly with the concentration of Ce ion in the sol. Moreover, it was verified that, for the nominal concentration of 0.05 M Ce ion in the sol, the Ce atomic fraction increased in the hybrid film, while the Si atomic fraction reduced, indicating the possible modification on the silane network due to the incorporation of Ce ions.