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Protective film formation on AA2024-T3 aluminum alloy by leaching of lithium carbonate from an organic coating

Liu, Y. (author), Visser, P. (author), Zhou, X. (author), Lyon, S.B. (author), Hashimoto, T. (author), Curioni, M. (author), Gholinia, A. (author), Thompson, G.E. (author), Smyth, G. (author), Gibbon, S.R. (author), Graham, D. (author), Mol, J.M.C. (author), Terryn, H.A. (author)

An investigation into corrosion inhibition properties of a primer coating containing lithium carbonate as corrosion inhibitive pigment for AA2024 aluminum alloy was conducted. It was found that, during neutral salt spray exposure, a protective film of about 0.2 to 1.5 ?m thickness formed within the area where an artificial defect was introduced...

journal article 2015

document

Fourier series for eclipses on exoplanet binaries

Visser, P.M. (author), Mol, M.A. (author)

Context. A double planet system or planet binary undergoes eclipses that modify the reflective light curve. In the time domain, the eclipse events are fast and weak. This would make their signal difficult to find and recognize in the phase light curve, even for small inclinations when eclipses happen frequently. However, due to the quasiperiodic...

journal article 2020

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

Kosari, A. (author), Ahmadi, M. (author), Tichelaar, F.D. (author), Visser, P. (author), Gonzalez Garcia, Y. (author), Zandbergen, H.W. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

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,...

journal article 2021

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

Michailidou, E. (author), Visser, P. (author), Mol, J.M.C. (author), Kosari, A. (author), Terryn, H.A. (author), Baert, K. (author), Gonzalez Garcia, Y. (author)

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...

journal article 2023

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Li leaching from Li carbonate-primer: Transport pathway development from the scribe edge of a primer/topcoat system

Visser, P. (author), Ranade, S. (author), Laird, J. S. (author), Glenn, A. M. (author), Hughes, A. E. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Depletion depths of inorganic components from a scribe edge in a polyurethane primer containing Li₂CO₃, MgO, BaSO₄ and TiO₂ beneath a topcoat, were determined using a range of techniques including SEM/EDS and proton induced X-ray and γ-ray emission spectroscopies. SEM of sections cut using an ion...

journal article 2021

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Nanoscopic and in-situ cross-sectional observations of Li-based conversion coating formation using liquid-phase TEM

Kosari, A. (author), Tichelaar, F.D. (author), Visser, P. (author), Taheri, P. (author), Zandbergen, H.W. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Lithium salts have been proposed as promising environmentally friendly alternatives to carcinogenic hexavalent chromium-based inhibitors for the corrosion protection of aerospace aluminium alloys (AAs). Incorporated into organic coatings, lithium salts are released at damaged locations to establish a conversion layer in which distinct...

journal article 2021

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Laterally-resolved formation mechanism of a lithium-based conversion layer at the matrix and intermetallic particles in aerospace aluminium alloys

Kosari, A. (author), Tichelaar, F.D. (author), Visser, P. (author), Zandbergen, H.W. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Lithium leaching coatings have recently been developed as eco-friendly active corrosion protection technology for aerospace aluminium alloys (AAs) by the formation of a conversion layer at coating defects. While general conversion layer formation characteristics were studied and reported before, here we study the local layer formation process...

journal article 2021

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Challenges to electrochemical evaluation of nanometric sandwiched thin specimens using liquid cells designed for application in liquid-phase TEM corrosion studies

Kosari, A. (author), Zandbergen, H.W. (author), Tichelaar, F.D. (author), Visser, P. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Liquid-phase transmission electron microscopy (LP-TEM) has provided corrosion scientists with a unique opportunity to directly correlate nanoscopic morphological and compositional evolutions to the corresponding electrochemical response of corroding thin TEM specimens. Electrochemical liquid cell designs are key components of a LP-TEM study...

journal article 2021

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

Li, Z. (author), Homborg, A.M. (author), Gonzalez Garcia, Y. (author), Kosari, A. (author), Visser, Peter (author), Mol, J.M.C. (author)

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,...

journal article 2022

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

Li, Z. (author), Homborg, A.M. (author), Gonzalez Garcia, Y. (author), Visser, Peter (author), Soleimani, M. (author), Mol, J.M.C. (author)

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...

journal article 2023

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On the importance of irreversibility of corrosion inhibitors for active coating protection of AA2024-T3

Visser, P. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Inhibitor leaching, fast, effective and irreversible passivation are essential for active protective coatings to protect aluminium alloys. This study presents the comparison of the active protective properties of lithium carbonate and two organic corrosion inhibitors, benzotriazole and 2-mercaptobenzothiazole, on aluminium alloy 2024-T3 with...

journal article 2018

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

Li, Z. (author), Visser, Peter (author), Hughes, Anthony E. (author), Homborg, A.M. (author), Gonzalez Garcia, Y. (author), Mol, J.M.C. (author)

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...

journal article 2024

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Hybrid sol-gel coatings applied on anodized AA2024-T3 for active corrosion protection

del Olmo, R. (author), Tiringer, U. (author), Milošev, I. (author), Visser, P. (author), Arrabal, R. (author), Matykina, E. (author), Mol, J.M.C. (author)

The effect of the presence of an anodic film and hybrid sol-gel coating loaded with corrosion inhibitors was evaluated as a strategy for enhanced barrier and active corrosion protection of aluminium alloy 2024-T3. In this study, AA2024-T3 specimens were anodized in a modified sulphuric-citric acid bath (SCA) as the first layer of a corrosion...

journal article 2021

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

Li, Z. (author), Li, G. (author), Visser, Peter (author), Homborg, A.M. (author), Gonzalez Garcia, Y. (author), Mol, J.M.C. (author)

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....

journal article 2023

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Lithium salts as leachable corrosion inhibitors and potential replacement for hexavalent chromium in organic coatings for the protection of aluminum alloys

Visser, P (author), Liu, Y (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Lithium salts are being investigated as leachable corrosion inhibitor and potential replacement for hexavalent chromium in organic coatings. Model coatings loaded with lithium carbonate or lithium oxalate demonstrated active corrosion inhibition and the formation of a protective layer in a damaged area during neutral salt spray exposure. The...

journal article 2016

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Particle induced gamma and X-ray emission spectroscopies of lithium based alloy coatings

Laird, Jamie S. (author), Hughes, Anthony E. (author), Ryan, C.J. (author), Visser, P (author), Terryn, H.A. (author), Mol, J.M.C. (author)

Lithium based inhibitors in aerospace coatings are seen as excellent replacements for their chromium counterparts which are both carcinogenic and heavier. However, Li is generally difficult to detect and following changes in its distribution due to corrosion is impossible with many standard techniques. Combining MeV Particle Induced Gamma and...

journal article 2017

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

Visser, P. (author), Meeusen, M. (author), Gonzalez Garcia, Y. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

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...

journal article 2017

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Particle characterisation and depletion of Li₂CO₃ inhibitor in a polyurethane coating

Hughes, Anthony (author), Laird, James (author), Ryan, Chris (author), Visser, P. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

The distribution and chemical composition of inorganic components of a corrosion-inhibiting primer based on polyurethane is determined using a range of characterisation techniques. The primer consists of a Li2CO3 inhibitor phase, along with other inorganic phases including TiO2, BaSO4 and Mg-(hydr)oxide. The characterisation techniques included...

journal article 2017

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Compositional study of a corrosion protective layer formed by leachable lithium salts in a coating defect on AA2024-T3 aluminium alloys

Marcoen, Kristof (author), Visser, P (author), Trindade, G. F. (author), Abel, M. L. (author), Watts, J. F. (author), Mol, J.M.C. (author), Terryn, H.A. (author), Hauffman, T. (author)

Organic primer coatings loaded with environmentally harmful Cr(VI) corrosion inhibitive pigments still play an important role in corrosion protection of aluminium alloys for the aerospace industry. A potential “green” alternative coating system has recently been developed, loaded with lithium salt corrosion inhibitors. Under exposure to...

journal article 2018

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The use of odd random phase electrochemical impedance spectroscopy to study lithium-based corrosion inhibition by active protective coatings

Meeusen, M. (author), Visser, P. (author), Fernández Macía, L. (author), Hubin, A. (author), Terryn, H.A. (author), Mol, J.M.C. (author)

In this work, the study of the time-dependent behaviour of lithium carbonate based inhibitor technology for the active corrosion protection of aluminium alloy 2024-T3 is presented. Odd random phase electrochemical impedance spectroscopy (ORP-EIS) is selected as the electrochemical tool to study the corrosion protective properties of a model...

journal article 2018