The Behavior of Implanted Xenon When Used as a Marker during the Anodic Oxidation of Aluminum: Evidence for an Explanation of a Dose‐Dependant Splitting Effect

Thomas, Jean-Paul; Fallavier, M.; Spender, P.; Francois, E. E.

doi:10.1149/1.2129716

Cited by 13 publications

(3 citation statements)

References 10 publications

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“…Thus, it is possible to explain the large value of TA~ 3+ obtained in the present study by the movement of phosphate inwards according to the electric field. However, it is notable that the transport number obtained by the marker method is dependent on the pre-existing films (14) and the acceleration voltage at the ion implantation of the marker (15). Dissolution characteristics of the oxide.--As can be seen from Fig.…”

Section: Discussionmentioning

confidence: 98%

Distribution of Anions and Protons in Oxide Films Formed Anodically on Aluminum in a Phosphate Solution

Takahashi

Fujimoto

Konno

et al. 1984

J. Electrochem. Soc.

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Pure A1 foil specimens were galvanostatically anodized in a neutral phosphate solution (pH = 7.0, 20~ and the thickness and composition profile of the formed oxide films were examined as functions of the anode potential and current density (c.d.). Analysis of the films was made by chemical sectioning with a H2SO4 solution, combined with (i) electron microscopy, (ii) x-ray photoelectron spectroscopy, (iii) capacitance measurements, (iv) dc polarization measurements, and (v) solution analysis. The films were found to consist of two parts, an outer part containing PO43-and OHions, and an inner part consisting of pure alumina. The outer part dissolved in the H~SO4 solution at a rate faster than that of the inner part, and thus the two parts were clearly distinguished by following the time variations in the reciprocal of capacitance during the chemical sectioning. For films formed with a constant c.d., the thickness ratio of the two parts, 6out/6~n, and the phosphate concentration in the outer part do not change with the anode potential or the total film thickness. With increasing c.d., the two values tend to increase. The mechanism controlling the anion and proton distribution in the oxide film is discussed.Anodic oxide films formed on aluminum contain an appreciable amount of anions brought from the anodizing solution. When anodizing in phosphate solutions, the incorporated anions locate in the outer part of the film, while an inner part next to the metal consists of stoichiometric oxide. This was first reported ]~y Randall and Bernard (1), who used a radiotracer method combined with a film sectioning technique. Using SIMS, Wood and co-workers (2) obtained phosphorus profiles qualitatively similar to those reported by Randall. More recently, we applied XPS combined with chemical sectioning of the film and ascertained that phosphorus in the outer part exists in the form of PO43-and that some protons are also incorporated in the outermost part of the oxide (3).Lanford et al. (4) measured hydrogen profiles for a variety of anodic oxide films using a nuclear reaction technique, and reported that protons exist only in the outermost part, at concentrations equivalent to about 1 mole percent (m/o) water in alumina.The purpose of the present investigation was to obtain quantitative measurements of the phosphate and proton profiles of oxide films formed galvanostatically in a phosphate solution and also to examine the effects of the anode potential and current density (c.d.) for films formed in phosphate solution at conditions similar to those used here. ExperimentalAnodizing procedure.--Pure, 99.99% A1 foil coupons (2 x 3 cm, tag shaped) were electropolished in a 4:1 mixture of glacial acetic acid and 60% perchloric acid at 10~176 by applying an anodic current of 100 mA/cm 2. The polished coupons were then immersed in a 20 g/1 CRO3-35 mYl H3PO4 solution (90~ for 20 min to remove oxide film formed during the electropolishing, washed with methanol, and dried. Anodizing was carried out in a 0.033M NH4H2PO4-0.067M (NH4)2HPO4 so...

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Section: Discussionmentioning

confidence: 98%

Distribution of Anions and Protons in Oxide Films Formed Anodically on Aluminum in a Phosphate Solution

Takahashi

Fujimoto

Konno

et al. 1984

J. Electrochem. Soc.

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“…The positioning of the marker in an anodic film is preferred to a location within the metal, since a marker located in the metal may remain at the metal/film interface. [21] Thus, in the present work, the argon incorporated into the alloy during sputtering is considered an unreliable marker for assessing ion migration. Nevertheless, the burial of the argon within the anodic film formed in ammonium pentaborate and sodium hydrogen phosphate electrolytes and the presence of argon near the surface of the anodic film formed in phosphoric acid electrolyte suggest that the films form by counter migration of metal and oxygen species.…”

Section: Film Growth In Sodium Hydrogen Phosphate and Ammonium Pentabmentioning

confidence: 99%

Incorporation and migration of phosphorus species within anodic films on an Al‐W alloy

Garcia-Vergara

Молчан

Zhou

et al. 2011

Surface & Interface Analysis

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The effect of tungsten species on the incorporation and migration of phosphorus species within anodic alumina is investigated. The study employs barrier anodic films, formed on a sputtering-deposited Al-15at.%W alloy in phosphate electrolytes. The films consist of either an outer tungsten-containing region and an inner tungsten-free region, or a tungsten-containing region only. Phosphorus species are shown to migrate inward in the tungsten-containing alumina more slowly than in the tungsten-free alumina. In contrast, the outward migration of tungsten species is relatively unaffected by the presence of phosphorus species. The relevance of the results to the use of tungsten tracers for the study of porous film growth is discussed.

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“…The local oxidation has been attributed to the presence of tungsten-rich clusters in the enriched alloy layer [9], which move inwards relative to the original metal surface, carried by the retreating alloyfilm interface. Previous work has revealed similar transport of xenon, which has been suggested to be present as fine bubbles at the metal-film interface [19]. There is probably an adjustment of the enrichment of tungsten as the metal-film interface moves into regions of metal containing less tungsten.…”

Section: As Implantedmentioning

confidence: 78%

The behaviour of ion-implanted tungsten species during anodic oxidation of aluminium

Fernandes¹,

Ferreira²,

Jesus³

et al. 1998

J. Phys. D: Appl. Phys.

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Amorphous anodic oxide films have been formed at high efficiency on aluminium implanted with 3.0 × 10 20 W ions m −2 in order to study the behaviour of tungsten during film growth. The initial film is composed mainly of alumina because the outer layer of aluminium above the main implanted region of the substrate is oxidized. During this period, tungsten atoms, present in low concentrations in the aluminium, accumulate in a thin metal layer just beneath the anodic film. Subsequently, the main tungsten-implanted region is oxidized, with incorporation of tungsten and aluminium species into the anodic film at the metal-film interface in proportion to their concentrations in the metal. The incorporated tungsten species migrate outwards in the anodic film at about 0.34 times the rate of Al 3+ ions. After oxidation of the main tungsten-containing region, more dilute regions of metal containing about 1 at% W are consumed, with oxidation of aluminium and tungsten in the presence of a highly tungsten-enriched metal layer. The enrichment is initially equivalent to 15 ± 4 at% W, assuming that the enriched layer is 2 nm thick. However, later, as the metal-film interface reaches regions of metal containing about 0.1 at% W, the enriched layer contains significantly more tungsten than is usual for such dilute metal regions, indicating that tungsten is transported with the metal-film interface from metal regions of higher prior tungsten concentration as the film thickens.

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The Behavior of Implanted Xenon When Used as a Marker during the Anodic Oxidation of Aluminum: Evidence for an Explanation of a Dose‐Dependant Splitting Effect

Cited by 13 publications

References 10 publications

Distribution of Anions and Protons in Oxide Films Formed Anodically on Aluminum in a Phosphate Solution

Distribution of Anions and Protons in Oxide Films Formed Anodically on Aluminum in a Phosphate Solution

Incorporation and migration of phosphorus species within anodic films on an Al‐W alloy

The behaviour of ion-implanted tungsten species during anodic oxidation of aluminium

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