The corrosion protection of pure aluminium and its alloys AA2024-T3 and AA7075-T6 has been studied in 0.1 M NaCl with and without the addition of Ce(III) chloride, Ce(III) nitrate, Ce(III) acetate and Ce(IV) sulfate. The study of Ce(III) acetate has been scarce but is here shown to be the most effective of the cerium salts studied, especially for AA7075-T6. The inhibition effectiveness of cerium salts is: Ce(III) acetate > Ce(III) chloride > Ce(III) nitrate for the metals studied. Ce(IV) sulfate does not inhibit corrosion. Electrochemical potentiodynamic measurements were used to investigate the mechanism of inhibition by cerium salts. Immersion tests in 0.1 M NaCl, with and without the addition of Ce(III) chloride and Ce(III) acetate, were performed to determine the effects of the inhibitors on the extent of corrosion damage at the surface of all three metals. For pure aluminium the inhibitory effectiveness was 78.5%, 82.6% and 84.0% in the presence of 3 mM Ce(III) nitrate, chloride and acetate, respectively. For AA7075-T6 the values of 92.1%, 99.1% and 99.6% were obtained. The inhibitory effectiveness of cerium salts is shown to depend on a variety of factors: type of substrate, type of anion and salt concentration.

Carboxylic acids were investigated as a means to fabricate a superhydrophobic and corrosion resistant aluminum surface. Alkaline etching produced a hierarchically rough, superhydrophilic and hydroxylated Al surface which could then be modified by immersion in ethanol solution of carboxylic acids of different alkyl chain lengths, from hexanoic to octadecanoic. Acids with chain length longer than seven carbon atoms acted as corrosion inhibitors, but only those with long chains (e.g., octadecanoic acid) acted as a corrosion barrier and made the surface superhydrophobic with water contact angles over 150 degrees. The morphology, topography and chemical composition of unmodified Al and etched Al modified by carboxylic acids were studied using surface analytical tools (scanning electron microscopy with chemical analysis, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry). Modelling based on density functional theory was performed to help explain experimental observations and to provide a rationale of why only carboxylic acids with long enough chains were effective in reducing the rate of corrosion. The reason was attributed to their ability to form more stable and protective organic films. Aluminum surface prepared under appropriate conditions was superhydrophobic, corrosion resistant and durable and showed self-cleaning and delayed ice-melting properties.