The effect of fluoride ions on the electrochemical activity of aluminum

Radošević, Jagoda; Mentus, Z.; Djordjević, Aleksandar; Despić, A.R.

doi:10.1016/0022-0728(85)85066-x

Cited by 9 publications

(5 citation statements)

References 7 publications

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“…This suggests that the variation of the potential at the beginning of the immersion is dominated by the increase of the anodic current, due to both a higher Al oxidation rate and a larger anodic area. 42,47,48 This results in a change of the charge distribution and as a consequence increases both the ionic and electronic conductivity of the oxide film, which in turn enhances the rate of the electrochemical reactions, as the anodic dissolution of aluminum. The overall dissolution process of aluminum oxide in contact with F Ϫ has been proposed in Ref.…”

Section: Resultsmentioning

confidence: 99%

“…45,46 The unique accelerating effect of F Ϫ on the dissolution of aluminum is also partly attributed to its ability to replace some of the O 2Ϫ in the oxide layer because of the similar ionic radii ͓r(F Ϫ ) ϭ 0.136 nm and r(O 2Ϫ ) ϭ 0.14 nm͔. 42,47,48 This results in a change of the charge distribution and as a consequence increases both the ionic and electronic conductivity of the oxide film, which in turn enhances the rate of the electrochemical reactions, as the anodic dissolution of aluminum. The ionic conductivity is increased mainly because of the formation of Al 3ϩ vacancies in the lattice, which causes an increase of the transport rate of Al 3ϩ through the oxide by means of a vacancy-hopping mechanism.…”

Section: Resultsmentioning

confidence: 99%

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Chromate Conversion Coating on Aluminum Alloys

Campestrini¹,

Goeminne²,

Terryn

et al. 2004

J. Electrochem. Soc.

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The formation of chromate conversion coatings ͑CCCs͒ on commercially pure Al ͑AA1050͒ during immersion in a chromic/ hydrofluoric acid solution has been investigated. A film formation mechanism is proposed based on the combination of open circuit potential measurements and surface analysis techniques, such as Auger electron spectroscopy and atomic force microscopy. It is suggested that the conversion of the Al surface takes place in three distinct stages: activation of the surface, initiation of the film formation, and growth of the conversion layer. In addition to the classical approach, a sol-gel model was considered for the initiation and growth of the film. The effect of the free fluoride and chromic acid concentration was studied using a thermodynamic model, whereas the influence of the Al oxide film was investigated by forming an anodic barrier layer prior to the conversion process. It was shown that the rate-determining step in the CCC formation is the activation of the Al surface. Therefore, the morphology and structure of the conversion layer is determined not only by the bath composition but also by the thickness of the Al oxide film.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Chromate Conversion Coating on Aluminum Alloys

Campestrini¹,

Goeminne²,

Terryn

et al. 2004

J. Electrochem. Soc.

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show abstract

“…While, in the first place, the adsorption of OH − ions leads to sample passivation and to improvement of the properties of the protective oxide layer on the surface of Al, adsorption of Cl − ions can lead to depassivation of Al, that is to a local dissolution of Al. Chloride ion adsorption generally occurs at oxides' defects, such as minor cuts, dips, cracks, or pores, that is where the oxide thickness is smaller, and electric field is stronger [45][46][47][48]. This phenomenon can cause significant changes in the charge transfer as is happening in the inner, the so called Helmholtz part, of the electrochemical double layer.…”

Section: T (H)mentioning

confidence: 96%

The effect of small addition of tin and indium on the corrosion behavior of aluminium in chloride solution

Gudić

Smoljko

Kliškić

2010

Journal of Alloys and Compounds

106

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“…In mixed fluoride-chloride electrolytes, the passivation current also depends on the fluoride ion concentration [110]. Fluoride ions are also found to influence porous aluminium oxide formation in organic acid media [111].…”

Section: Aluminiummentioning

confidence: 99%

Electrochemistry of metals and semiconductors in fluoride media

Noel

Suryanarayanan

2005

J Appl Electrochem

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The electrochemical surface transformations and diverse applications of a variety of metals and semiconductors in a wide range of fluoride media such as aqueous, non-aqueous media, liquid HF media, room temperature fluoride melts and molten fluoride media with a melting range covering 50-1000°C are reviewed. Nickel shows excellent corrosion resistance in the absence of water. The anodic performance of this metal in electrochemical perfluorination and NF 3 production is discussed. Compact carbon materials serve as anodes in fluorine generators. In high temperature melts, they perform as consumable anodes. Graphitic carbon undergoes intercalation/ de-intercalation process and related battery applications. Cu/CuF 2 couple is a good reference electrode. Pt and vitreous carbon materials are the inert electrodes of choice for electro analytical applications. Electrodeposition of Lithium as a non-dendritic uniform phase is important in Lithium metal based secondary batteries. High temperature fluoride melts are used in electro-deposition of valve metals such as Nb, Ta, and Ti. The stability and decomposition of fluoride complexes in these media are of interest.

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The effect of fluoride ions on the electrochemical activity of aluminum

Cited by 9 publications

References 7 publications

Chromate Conversion Coating on Aluminum Alloys

Chromate Conversion Coating on Aluminum Alloys

The effect of small addition of tin and indium on the corrosion behavior of aluminium in chloride solution

Electrochemistry of metals and semiconductors in fluoride media

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