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

Journal article (2024)

Authors

Z. Li Team Arjan Mol - Mechanical, Maritime and Materials Engineering
A.M. Homborg Team Arjan Mol - Mechanical, Maritime and Materials Engineering , Netherlands Defence Academy
Peter Visser Akzo Nobel
Y. Gonzalez Garcia Team Yaiza Gonzalez Garcia - Mechanical, Maritime and Materials Engineering
J.M.C. Mol Team Arjan Mol - Mechanical, Maritime and Materials Engineering
Research Group
Team Arjan Mol (Mechanical, Maritime and Materials Engineering) (TU Delft)
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Published Date

2024

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Materials Science and Engineering

Research Group

Team Arjan Mol

Abstract

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 protective inner dense layer. For the freshly formed conversion layer, both the top and the inner layer undergo a gradual dissolution upon exposure to relatively dilute NaCl solution within 2 h due to their chemical instability. For the ambiently-aged conversion layer, most corrosion activity around IMPs is related to the S-phase and large constituent phases, due to their active nature and the lower local conversion layer quality, respectively. Moreover, S-phase-related corrosion activity lasts approximately 8 h due to fast dissolution whereas reactions induced by large constituent particles remain active over the entire re-immersion period of 12 h.