Effects of Ce-containing sol-gel coatings reinforced with SiO2 nanoparticles on the protection of AA2024

Abstract

A hybrid organic-inorganic self-healing coating for anticorrosive protection of AA2024 was developed through the sol-gel method. Combination of permeability, provided by a methacrylate-silica hybrid matrix, with hardness and density of silica nanoparticles, allowed obtaining a coating material where the diffusion of Ce ions occurred at the same time that an anticorrosive physical barrier was developed. Electrochemical impedance spectra (EIS) on coated samples showed an increase of the impedance modulus at 0.01 Hz as a function of immersion time in a 3.5 wt% NaCl solution. Self-healing effect was verified by impedance fitting through the evolution of resistive and capacitive parameters of the equivalent circuits.