Review of the state of art of Li-based inhibitors and coating technology for the corrosion protection of aluminium alloys

The quest for novel alternatives to hexavalent-chromium-based corrosion inhibitors is of utmost significance and urgency. Strict international health and safety regulations, due to growing concerns regarding the impact of hexavalent chromium on human health and the environment, have pushed the commercial introduction of many alternative...

Spatiotemporally resolved corrosion protection of AA2024-T3 by a lithium-based conversion layer

In this work, the corrosion mechanism of AA2024-T3 covered by a lithium-based conversion layer is studied with high spatial and temporal resolution. Although the aluminium alloy surface is protected by a multi-layered conversion layer, areas around intermetallic phases (IMPs) represent weak spots due to an insufficient generation of a...

The effect of pH on the corrosion protection of aluminum alloys in lithium-carbonate-containing NaCl solutions

The corrosion inhibiting effect of lithium carbonate has been studied over the pH range relevant for atmospheric corrosion conditions at the polymer/metal interface. It is demonstrated that lithium carbonate offers optimum corrosion protection under moderately alkaline conditions attributed to the formation of a protective layer identified as...

The Effect of Ambient Ageing on the Corrosion Protective Properties of a Lithium-Based Conversion Layer

The influence of ageing under ambient conditions on the corrosion protective behaviour of a lithium-based conversion layer on AA2024-T3 is studied in this work. Conversion layers aged at ambient conditions for relatively short times (0 h and 4 h), show an initial high degree of corrosion inhibition but a much lower protectiveness after the...

Local scanning electrochemical microscopy analysis of a lithium-based conversion layer on AA2024-T3 at progressive stages of formation

Scanning electrochemical microscopy (SECM) is employed to characterize the evolution of local electrochemical surface activity during lithium-based conversion layer formation on legacy aerospace aluminium alloy AA2024-T3. Initially, three types of studied intermetallic particles - S-, θ- and constituent phases - act as active cathodic areas....

Evaluation of the formation and protectiveness of a lithium-based conversion layer using electrochemical noise

The formation process of a lithium-based conversion layer on AA2024-T3 and its corrosion protective behavior are studied using electrochemical noise (EN). Wavelet transform, as well as noise resistance analysis, have been employed to interpret the EN data. The EN data confirmed five different stages during the conversion layer growth,...

Editors' Choice - Dealloying-Driven Cerium Precipitation on Intermetallic Particles in Aerospace Aluminium Alloys

Cerium-based compounds have been studied for decades as non-toxic candidates for the protection of aerospace aluminium alloys (AAs) like AA2024-T3. However, the complex heterogeneous microstructure of these alloys has hindered a thorough understanding of the subsequent stages of corrosion protection provided by this class of inhibitors. Thus,...

Mechanism of passive layer formation on AA2024-T3 from alkaline lithium carbonate solutions in the presence of sodium chloride

This study focuses on the elucidation of the formation mechanism of passive layers on AA2024-T3 during the exposure to alkaline lithium carbonate solutions in the presence of sodium chloride. Under controlled conditions, in an electrochemical cell, a protective layer was generated comprising an amorphous inner layer and a crystalline outer...

Electrochemical evaluation of corrosion inhibiting layers formed in a defect from lithium-leaching organic coatings

This work presents the electrochemical evaluation of protective layers generated in a coating defect from lithium-leaching organic coatings on AA2024-T3 aluminum alloys as a function of neutral salt spray exposure time. Electrochemical impedance spectroscopy was used to study the electrochemical properties on a macroscopic scale. An...