Oxide formation on aluminium alloys in boiling deionised water and NaCl, CeCl3 and CrCl3 solutions

Gorman, J.D.; Hughés, A.E.; Jamieson, David N.; Paterson, Peter J.

doi:10.1016/s0010-938x(02)00209-3

Cited by 48 publications

(33 citation statements)

References 28 publications

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“…9). The formation of needle like structure (boehmite) on the surface of aluminium has been reported by many researchers [15,29,30] due to the effect of hydrogen gas evolution. Supporting the above arguments, the GD-OES chemical analysis profile showed the presence of diffused hydrogen near the surface of the substrate at the substrateoxide interface.…”

Section: Discussionmentioning

confidence: 95%

Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

Din

Gudla

Jellesen

et al. 2015

Surface and Coatings Technology

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Section: Discussionmentioning

confidence: 95%

Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

Din

Gudla

Jellesen

et al. 2015

Surface and Coatings Technology

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“…• C for 1h according to the method of Gorman et al 18 The Li-LDH reference was prepared by immersing a AA2024-T3 panel in a 0.1 M Li 2 CO 3 solution (pH = 11.3) for 15 min using the conversion coating process of Buchheit et al 6 Following the treatment, the panels were rinsed with deionized water for 5 min and dried at the air.…”

mentioning

confidence: 99%

Mechanism of Passive Layer Formation on AA2024-T3 from Alkaline Lithium Carbonate Solutions in the Presence of Sodium Chloride

Visser

González-García

Mol

et al. 2018

J. Electrochem. Soc.

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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-layer. In order to resolve the formation mechanism, the layers were characterized using surface analytical techniques to characterize the surface morphology, thickness and elemental composition of the layers at different stages of the formation process. In addition, electrochemical techniques were applied to link the electrochemical properties of the layers with the different stages of formation. The results demonstrate that the formation mechanism of these layers comprises three different stages: (I) oxide thinning, (II) anodic dissolution and film formation, followed by (III) film growth through a competitive growth-dissolution process. The passive properties of the layers are generated in the third stage through the densification of the amorphous layer. The combined results provide an enhanced insight in the formation mechanism and the development of the passive properties of these layers when lithium salts are used as leaching corrosion inhibitor for coated AA2024-T3. Lithium salts gained interest as corrosion inhibitor after the observations of unexpected passivity of aluminum in alkaline lithium solutions by Gui and Devine.1 Aluminum is stable in the range of pH 4 to pH 9 due to the passivity of aluminum oxide.2 However, it is known that aluminum shows a high corrosion rate at pH values higher than 10.3 The corrosion process under these alkaline conditions is dominated by two subsequent sub-processes leading to significant mass loss. First, there is the process of direct (anodic) dissolution of the aluminum metal and the formation of an amorphous aluminum hydroxide gel film on the aluminum substrate, and second, the process of chemical dissolution of the aluminum hydroxide gel film into the bulk solution.4 In contrast, aluminum shows a passive behavior by the formation of a lithium containing film when exposed to alkaline lithium salt solutions. 1,5 This passive behavior was implemented by Buchheit et al. with the development of a hexavalent chromium-free chemical conversion coating from alkaline lithium carbonate solutions (pH 11-13), generating lithium aluminum carbonate hydroxide hydrate (hydrotalcite) layers on aluminum alloys.6 They studied the composition, structure and performance of these conversion coatings in relation to processing parameters and various bath chemistries and demonstrated that these hydrotalcite coatings exhibit similar corrosion protective properties as traditional conversion coatings.7 However, application of these conversion coatings in combination with coatings did not result in an equal performance compared to hexavalent chromium-based conversion coatings. In 2010, it was discovered that lithium salts could be considered as a potential alte...

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“…Gorman et al 157 found that the oxide thickness was the same for a range of different alloys (AA1100, AA2024-T3, AA3004-H19, AA5005-O, AA6061-T6 and AA7075-T6), suggesting no infl uence of the alloy surface composition on formation and growth of pseudoboehmite in distilled water. After treatment in NaCl, however, the oxides were thicker but there was little difference between the different alloys.…”

Section: Boehmite Formation In Solutions Containing Rare Earthsmentioning

confidence: 99%

“…156 As the oxides are only sparingly soluble, then once the reaction proceeds these ions precipitate onto the surface forming either bayerite (Al(OH) 3 ) and pseudoboehmite, at low temperatures (<50 °C), or pseudoboehmite alone at more elevated temperatures (>80 °C). 156 As O/Al ratios of 3 were measured on these surfaces by XPS, 157 The presence of cerium ions in solution results in different oxide thicknesses between different Al-alloys after treatment suggesting an active role for the cerium cations and the alloy surface microstructure and/or composition. 157 Alwitt observed that at 100 °C the pseudoboehmite layer develops an impenetrable inner layer because of the high density of crystallization.…”

Section: Boehmite Formation In Solutions Containing Rare Earthsmentioning

confidence: 99%

“…156 As O/Al ratios of 3 were measured on these surfaces by XPS, 157 The presence of cerium ions in solution results in different oxide thicknesses between different Al-alloys after treatment suggesting an active role for the cerium cations and the alloy surface microstructure and/or composition. 157 Alwitt observed that at 100 °C the pseudoboehmite layer develops an impenetrable inner layer because of the high density of crystallization. On the basis of radio tracer measurements it was concluded that the rate limiting step at 100 °C for the third stage of growth is solid state diffusion of water across the impenetrable layer.…”

Section: Boehmite Formation In Solutions Containing Rare Earthsmentioning

confidence: 99%

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Oxide formation on aluminium alloys in boiling deionised water and NaCl, CeCl3 and CrCl3 solutions

Cited by 48 publications

References 28 publications

Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

Mechanism of Passive Layer Formation on AA2024-T3 from Alkaline Lithium Carbonate Solutions in the Presence of Sodium Chloride

Coatings for corrosion prevention based on rare earths

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