Influence of the anodizing temperature on the porosity and the mechanical properties of the porous anodic oxide film

Aerts, Tim; Dimogerontakis, Th.; Graeve, Iris De; Fransaer, Jan; Terryn, Herman

doi:10.1016/j.surfcoat.2007.01.044

Cited by 209 publications

(126 citation statements)

References 16 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, few studies have been conducted on the anodization of low-purity aluminum. [21][22][23][24][25][26][27][28][29] Fabrication of anodic alumina membranes from low-purity aluminum foil is not trivial and often requires specific conditions, different from those typically applied to the anodization of high-purity aluminum. 29 Herein, we use two different aluminum foils which are high purity (99.999%) and relatively low purity (99.8%) to fabricate a porous alumina membrane.…”

Section: Introductionmentioning

confidence: 99%

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

Kim¹,

Lee

2014

Bulletin of the Korean Chemical Society

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Anodic alumina oxide (AAO), a self-ordered hexagonal array, has various applications in nanofabrication such as the fabrication of nanotemplates and other nanostructures. In order to obtain highly ordered porous alumina membranes, a two-step anodization or prepatterning of aluminum are mainly conducted with straight electric field. Electric field is the main driving force for pore growth during anodization. However, impurities in aluminum can disturb the direction of the electric field. To confirm this, we anodized two different aluminum foil samples with high purity (99.999%) and relatively low purity (99.8%), and compared the differences in the surface morphologies of the respective aluminum oxide membranes produced in different electric fields. Branched pores observed in porous alumina surface which was anodized in low-purity aluminum and the size; dimensions of the pores were found to be usually smaller than those obtained from high-purity aluminum. Moreover, anodization at high voltage proceeds to a significant level of conversion because of the high speed of the directional electric field. Consequently, anodic alumina membrane of a specific morphology, i.e., meshed pore, was produced.

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Section: Introductionmentioning

confidence: 99%

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

Kim¹,

Lee

2014

Bulletin of the Korean Chemical Society

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“…The growth of the porous anodic film is usually considered to be a complex process resulting from antagonistic reactions: the electrochemical oxidation of the metal substrate to the Al 2 O 3 film, and the chemical dissolution of the anodic layer in highly acidic conditions. The characteristics of the resulting porosity depend on various operational parameters, such as the aluminium alloy used (Konieczny et al, 2004), the experimental anodizing conditions (content, stirring and the bath temperature (Aerts et al, 2007)) and the electrical conditions (Regone et al, 2006). Our results show that the anodic film on AA 7175T7351, includes an erratic spongy structure, clearly different from Keller's long-established model (Keller et al, 1953) made up of regular hexagonal cells, each including a straight central pore perpendicular to the initial substrate surface.…”

Section: Resultsmentioning

confidence: 74%

Black anodic coatings for space applications: Study of the process parameters, characteristics and mechanical properties

Goueffon

Arurault

Mabru

et al. 2009

Journal of Materials Processing Technology

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 2628 AbstractBlack inorganic anodized aluminium alloys are used for managing passive thermal control on spacecraft and for avoiding stray light in optical equipment. Spalling of these coatings has sometimes been observed after thermal cycling on 2XXX and 7XXX aluminium alloys. This phenomenon could generate particulate contamination in satellites and may affect mission lifetime. In this work, the influences of the four main steps of the process (pretreatments, sulphuric anodizing, colouring and sealing) on the coating characteristics have been studied for a 7175 T7351 aluminium alloy. The chemical heterogeneity of the coating has been underlined, 2 and its mechanical behaviour observed through crazing. Scratch-testing, used to evaluate coating adhesion to its substrate, revealed the negative impact of thermal cycling.

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“…The H 3 O + species (the agent promoting dissolution) is repelled from the anodic specimen surface thus the dissolution process is likely to be influenced by temperature. The net effect is a noticeable increase in the rate of dissolution at the surface with increasing acid temperature, promoting pore mouth widening [13].…”

Section: Discussionmentioning

confidence: 99%

Optimising sulfuric acid hard coat anodising for an Al-Mg-Si wrought aluminium alloy

Bartolo

Sinagra

Mallia

2014

Materials Science-Poland

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This research evaluates the effects of sulfuric acid hard coat anodising parameters, such as acid concentration, electrolyte temperature, current density and time, on the hardness and thickness of the resultant anodised layers. A small scale anodising facility was designed and set up to enable experimental investigation of the anodising parameters. An experimental design using the Taguchi method to optimise the parameters within an established operating window was performed. Qualitative and quantitative methods of characterisation of the resultant anodised layers were carried out. The anodised layer's thickness, and morphology were determined using a light optical microscope (LOM) and field emission gun scanning electron microscope (FEG-SEM). Hardness measurements were carried out using a nano hardness tester. Correlations between the various anodising parameters and their effect on the hardness and thickness of the anodised layers were established. Careful evaluation of these effects enabled optimum parameters to be determined using the Taguchi method, which were verified experimentally. Anodised layers having hardness varying between 2.4 -5.2 GPa and a thickness of between 20 -80 µm were produced. The Taguchi method was shown to be applicable to anodising. This finding could facilitate on-going and future research and development of anodising, which is attracting remarkable academic and industrial interest.

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Influence of the anodizing temperature on the porosity and the mechanical properties of the porous anodic oxide film

Cited by 209 publications

References 16 publications

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

Effect of Aluminum Purity on the Pore Formation of Porous Anodic Alumina

Black anodic coatings for space applications: Study of the process parameters, characteristics and mechanical properties

Optimising sulfuric acid hard coat anodising for an Al-Mg-Si wrought aluminium alloy

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