Effects of the hydrogen content on the development of anodic aluminum oxide film on pure aluminum

Shih, Teng Shih; Chen, Po Chen; Huang, Yung Sen

doi:10.1016/j.tsf.2011.05.066

Cited by 15 publications

(2 citation statements)

References 28 publications

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“…This indicates the formation of an occluded void under the reaction product dome, similar to severe pitting process. Since Al(OH) 3 hydrated oxide tends to form on the AAO surface, 43 pitting is prone to initiate at the AAO surface where Al(OH) 3 is highly concentrated. 44 The deposited particle in Fig.…”

Section: Skpfm Evaluation Of Corrosion Tendency Of Impsmentioning

confidence: 99%

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

Zhang

Nilsson²,

Pan

2016

J. Electrochem. Soc.

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In this study, anodization of an Al 6060 alloy has been investigated by in-situ electrochemical atomic force microscopy (EC-AFM) and electrochemical impedance spectroscopy (EIS) under operando conditions, to elucidate the role of intermetallic particles (IMPs) in the alloy. The Volta potential maps measured by scanning Kelvin probe force microscopy (SKPFM) reveal that the relative nobility is higher for AlFeSi type and lower for Mg2Si type of particles as compared with the alloy matrix. The EIS results obtained at anodizing potentials show that the thickness of the barrier oxide layer increases linearly with the applied potential, but the oxide growth rate is lower than that of single crystal samples reported previously. Moreover, the EIS spectra show an inductive loop at low frequencies indicating an anodic dissolution process. The EC-AFM images display detailed morphological changes related to the IMPs during the anodization, which reveal certain localized dissolution in parallel to anodic Al oxide (AAO) formation on the alloy. The combined AFM and EIS measurements demonstrate that the IMPs in the alloy cause localized dissolution during anodization, resulting in a reduced AAO growth rate. The corrosion resistance of as-produced AAO film is low unless anodized at sufficiently high potential.

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Section: Skpfm Evaluation Of Corrosion Tendency Of Impsmentioning

confidence: 99%

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

Zhang

Nilsson²,

Pan

2016

J. Electrochem. Soc.

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“…Hydrogen content was slightly decreased at matrix close to f/m interface. 31,32) Hydrogen content test that prepared from subsurface area and from core portion of anodized specimens respectively as listed in Table 2. The data indeed show lower hydrogen content on sample taking from subsurface than that from the core portion.…”

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confidence: 99%

The Effects of Anodization Treatment on the Microstructure and Fatigue Behavior of 7075-T73 Aluminum Alloy

Shih

Lee

2014

Mater. Trans.

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The fatigue behaviors of 7075-T73 alloy with/without anodization/sealing treatment were investigated in this study. The microstructure of different samples was analyzed by electron microscopy. As the experiments, the microstructure were observed from the anodized/sealed samples to indicate that precipitates trapped at subsurface near film/metal (f/m) interface would partly dissolved and the deformed matrix existed high fractions of high angle grain boundaries. The bare 7075-T73 alloy samples achieved fatigue strength of 225 MPa and the anodized/sealed samples enhanced their fatigue strength at 10 7 life cycles with 1020 µm film thickness. The fractured anodized/sealed sample showed fine striation spacing than bare sample after subjected to low stress amplitude.

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Atomistic Modeling of Corrosion Resistance: A First Principles Study of O₂ Reduction on the Al(111) Surface Covered with a Thin Hydroxylated Alumina Film

Costa

Ribeiro

Mercuri

et al. 2014

Adv Materials Inter

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In the early stage of corrosion of Al or Al alloys (i.e., during the initiation of localized corrosion), an oxide film is generally present on the surface. This work investigates the possibility for a cathodic reaction to occur on these oxide films. We discuss realistic models of supported oxide films on Al(111) in order to disentangle the factors determining the reactivity towards O2. Three components of the complex film formed on Al(111) can be identified: an ultrathin under‐stoichiometric AlxOy interface layer, an intermediate Al2O3 phase with γ‐alumina structure, and an hydroxylated AlOOH surface termination with boehmite structure. The electron transfer to O2 molecules depends on the workfunction, Φe, of the metal/oxide interface and on the thickness of the inner Al2O3 phase. The electron transfer takes place both from the metal‐oxide interface and the oxide surface to the adsorbed O2 molecule. Very important is the role of the hydroxyl groups at the surface: they eliminate the Al surface states and stabilize the surface; they allow the reduced O2 − species to capture protons and transform into hydrogen peroxide in a non‐activated process. H2O2 is further reduced to two water molecules, in a series of two‐electron mechanisms. These reactions take place only when the internal alumina phase is ultrathin (here 0.2 nm). As soon as an Al2O3 inner layer develops (film thickness of about 1 nm), the film becomes unreactive and passivates the Al(111) surface. The results help to shed light on the complex reactions responsible for metal corrosion.

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Effects of the hydrogen content on the development of anodic aluminum oxide film on pure aluminum

Cited by 15 publications

References 28 publications

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

The Effects of Anodization Treatment on the Microstructure and Fatigue Behavior of 7075-T73 Aluminum Alloy

Atomistic Modeling of Corrosion Resistance: A First Principles Study of O₂ Reduction on the Al(111) Surface Covered with a Thin Hydroxylated Alumina Film

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Effects of the hydrogen content on the development of anodic aluminum oxide film on pure aluminum

Cited by 15 publications

References 28 publications

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

In Situ and Operando AFM and EIS Studies of Anodization of Al 6060: Influence of Intermetallic Particles

The Effects of Anodization Treatment on the Microstructure and Fatigue Behavior of 7075-T73 Aluminum Alloy

Atomistic Modeling of Corrosion Resistance: A First Principles Study of O2 Reduction on the Al(111) Surface Covered with a Thin Hydroxylated Alumina Film

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Atomistic Modeling of Corrosion Resistance: A First Principles Study of O₂ Reduction on the Al(111) Surface Covered with a Thin Hydroxylated Alumina Film