Elucidation of the Anodization and Silver Incorporation Impact on the Surface Properties of AA1050 Aluminum Alloy

Abstract

The recently increased interest toward the modification of anodized aluminum oxide (AAO) layers has motivated the present systematical research. The experiments were comprised of three groups of AA1050 alloy samples: preliminary treated, anodized and further AAO layer modification, using AC-assisted silver incorporation. The respective impact of the surface treatment was assessed using different analytical methods, in order to obtain systematical information on the variation of the surface properties, morphology and performance of the obtained Al-O-Ag films. The analyses included determination of the sample color, hydrophobicity and mechanical strength. These measurements were followed by characterization of their morphology by scanning electron microscopy and composition by energy dispersion X-ray analysis and X-ray photoelectron spectroscopy. These characterizations were completed by the assessment of the samples' performance, after 168 hours of exposure to a 3.5% NaCl model corrosive medium. The corrosion evaluation tests included electrochemical impedance spectroscopy and potentiodynamic scanning. The comparative analysis of the acquired results has enabled us to do a comprehensive description of the mechanism of the AC-assisted Ag-incorporation and its impact on the modified AAO films. The obtained Al-O-Ag functional layers have shown remarkable reliability, being appropriate for various industrial applications.

Evaluation of the electrochemical performance of Ag containing AAO layers after extended exposure to a model corrosive medium

“…The specific combination of the benefits provided by anodization and the further deposition of silver applied to the widely used low-doped aluminum alloy has inspired the present research on the surface characteristics and corrosion protective abilities of the resulting Al-O-Ag films in comparison to unmodified AAO layers and bare Al samples. In this sense, the present study is an extension of previous systematic research works [59,60] devoted to such electrochemically synthesized Al-O-Ag layers.…”

“…In a previous study [60], we have not succeeded to detect any silver traces on the surface of the Al-O-Ag system, because Ag deposition proceeds on the pore bottoms and walls, the present sample was preliminary scraped by 1200 grid sandpaper prior to XPS analysis. This approach has enabled to detect and analyze the silver deposits inside the pores of the oxide film.…”

“…The phenomenon of sulfur inclusion in AAO layers is described by Wernick et al [71] and Thompson et al. [72], and it was later confirmed at anodization of high doped [59,60] and low doped [61,62] aluminum alloys.…”

“…This explication seems more plausible than any suggestion related to alterations of the thickness of the basic porous AAO matrix, promoted by the electrochemical Al-O-Ag layer formation. Indeed, previous research has shown that the thickness of formed AAO layer under such conditions is about 20 μm [61,62] and the AC-assisted silver deposition does not result in alteration of the oxide layer thickness [59,60]. Consequently, the lower XRD plateau in the case of Al-O-Ag is probably a result of the quenching of the X-ray signal, reflected by the porous AAO matrix.…”

Characterization of Anodized Al 1050 with Electrochemically Deposited Cu, Ni and Cu/Ni and Their Behavior in a Model Corrosive Medium

“…For the present study, a simplified MEC was employed, compared to those in previous works [35,67,[70][71][72]. This simplified circuit was selected following the rule of thumb [69,[73][74][75], which imposes the use of the simplest possible equivalent circuit, that enables a high rate of fitting to the acquired spectra.…”