Anodic Oxidation of Aluminum

Tajima, S.

doi:10.1007/978-1-4615-8252-6_4

Cited by 47 publications

(11 citation statements)

References 112 publications

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“…These voltages correspond to alumina and titania thicknesses of about 14.0 nm [56] and 30.0 nm [55]. The formed alumina layers are described as amorphous or γ-and γ ′ -Al 2 O 3 [57,58]. In the case of TiO 2 , the stoichiometric modifications anatase, rutile and brookite, as well as non-stoichiometric phases were observed [55,59].…”

Section: Sample Preparationmentioning

confidence: 92%

Strong metal–support interactions on rhodium model catalysts

Linsmeier

Taglauer

2011

Applied Catalysis A: General

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Reactive processes on catalyst surfaces are studied in this work for Rh/metal oxide model systems by means of surface science techniques. Published results in the literature deal with titania, alumina, and silica as support materials and are briefly reviewed. For the present studies Rh/Al 2 O 3 and Rh/TiO 2 model catalysts with about one monolayer Rh coverage are specially prepared and analyzed by ion scattering spectroscopy, X-ray photoelectron spectroscopy, and thermal desorption measurements as main techniques. In part these measurements are supported by a variety of other analytical and imaging techniques. For thermal treatment in hydrogen atmosphere at low and elevated pressures a complete Rh encapsulation by titania is observed for temperatures above 773 K. The results from ion bombardment depth profiling are corroborated by the concomitant drastic reduction of the CO adsorption capacity of these samples. The model catalysts thus exhibit the typical features of 'strong metal-support interaction'. The effect was not found for alumina supports, for which thermal treatments mainly resulted in gradual interdiffusion of the various surface species. These results also demonstrate that characteristic catalyst behavior can be successfully studied by applying surface science methods to model catalysts.

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Section: Sample Preparationmentioning

confidence: 92%

Strong metal–support interactions on rhodium model catalysts

Linsmeier

Taglauer

2011

Applied Catalysis A: General

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“…A currently rapidly developing field is the creation of nanoscale structures and composite materials using porous anodic aluminum oxide as a highly ordered nanostructured matrix for the formation of various kinds of functional materials and devices [17][18][19][20][21][22][23][24][25][26], including nanostructures such as carbon nanotubes, nanodiamonds, and graphene [27][28][29]. The above-described PAFs implementations require research results on the effect of the electrolyte nature, electrical anodizing modes, and other factors on the cellular-porous structure parameters and the PAF properties both in traditional electrolytes [30][31][32][33][34][35][36][37][38][39][40] in various compositions [41][42][43] and unconventional acidic solutions [44][45][46][47][48][49][50][51]. It is known, for example, that galvanostatic anodizing of aluminum in acidic electrolyte can occur at different rates, depending on the electrolyte nature and concentration, and on the anodic current density [26,30].…”

Section: Introductionmentioning

confidence: 99%

Porous Alumina Films Fabricated by Reduced Temperature Sulfuric Acid Anodizing: Morphology, Composition and Volumetric Growth

et al. 2021

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The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5–10 mA·cm−2 current densities were investigated. It appeared that an increase in the solution concentration from 0.4 to 2 M has no significant effect on the anodizing rate, but leads to an increase in the porous alumina film growth. The volumetric growth coefficient increases from 1.26 to 1.67 with increasing current density from 0.5 to 10 mA·cm−2 and decreases with increasing solution concentration from 0.4 to 2.0 M. In addition, in the anodized samples, metallic aluminum phases are identified, and a tendency towards a decrease in the aluminum content with an increase in solution concentration is observed. Anodizing at 0.5 mA·cm−2 in 2.0 M sulfuric acid leads to formation of a non-typical nanostructured porous alumina film, consisting of ordered hemispheres containing radially diverging pores.

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“…It is known that the lower the acid concentration and temperature of electrolyte or the higher the current density, higher hardness and abrasion resistance are obtained due to the suppression of dissolution reaction. 6 Many researches are being conducted to establish the formation mechanism of porous alumina but there is no clear explanation to support the mechanism. 7 Wood et al reported that with constant current mode, cylindrical pores are obtained after the formation of pathways on surface similar to cracks from the inside of pores.…”

Section: Methodsmentioning

confidence: 99%

Determination of Sulfuric Acid Concentration for Anti-Cavitation Characteristics of Al Alloy by Two Step Anodizing Process to Forming Nano Porous

Lee¹,

Kim²,

Jeong³

et al. 2014

j nanosci nanotechnol

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Al alloy is a highly active metal but forms a protective oxide film having high corrosion resistance in atmosphere environment. However, the oxide film is not suitable for practical use, since the thickness of the film is not uniform and it is severly altered with formation conditions. This study focused on developing an aluminum anodizing layer having hardness, corrosion resistance and abrasion resistance equivalent to a commercial grade protective layer. Aluminum anodizing layer was produced by two-step aluminum anodizing oxide (AAO) process with different sulfuric acid concentrations, and the cavitation characteristics of the anodized coating layer was investigated. In hardness measurement, the anodized coating layer produced with 15 vol.% of sulfuric acid condition had the highest value of hardness but exhibited poor cavitation resistance due to being more brittle than those with other conditions. The 10 vol.% of sulfuric acid condition was thus considered to be the optimum condition as it had the lowest weight loss and damage depth.

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Anodic Oxidation of Aluminum

Cited by 47 publications

References 112 publications

Strong metal–support interactions on rhodium model catalysts

Strong metal–support interactions on rhodium model catalysts

Porous Alumina Films Fabricated by Reduced Temperature Sulfuric Acid Anodizing: Morphology, Composition and Volumetric Growth

Determination of Sulfuric Acid Concentration for Anti-Cavitation Characteristics of Al Alloy by Two Step Anodizing Process to Forming Nano Porous

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