Effect of Joule Heating on Formation of Porous Structure of Thin Oxalic Acid Anodic Alumina Films

Chernyakova, Katsiaryna; Vrublevsky, Igor; Klimas, Vaclovas; Jagminas, Arūnas

doi:10.1149/2.1001807jes

Cited by 18 publications

(13 citation statements)

References 34 publications

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“…3B), which agrees with D inter for anodizing in 0.3 M oxalic acid. 37 If we apply the equation, D inter = 2.41U a + 3.5, we get 196.3 nm. However, these cells are packed less tightly than oxalic acid films.…”

Section: Resultsmentioning

confidence: 99%

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Chernyakova

Jasulaitienė

Naujokaitis

et al. 2023

J. Electrochem. Soc.

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Morphology, composition, and fluorescence properties of anodic alumina/carbon composites formed in an aqueous solution of formic acid with ammonium heptamolybdate additive were studied concerning the amount and state of embedded carbon. According to scanning electron microscopy, the composites possess a hierarchical structure with multi-branched pores with a dense, cracked cover layer on the film surface. On the reverse side, hexagonal-shaped cells with an average diameter of about 180 nm were formed. Linear sweep voltammetry and current transient curves demonstrated that the anodizing process is non-steady. Thermogravimetry/differential thermal analysis showed that the average carbon content is ca. 5.5 mass.%. According to infrared spectroscopy, carbon embedded in the alumina is in the form of CO2, CO, carboxylate ions, and a-C:H. X-ray-induced Auger electron spectroscopy of the surface and reverse sides of the films proved that carbon is homogeneously distributed through the oxide layer. According to fluorescence studies, alumina/carbon composites have a wide blue fluorescence in the wavelength range of 350–700 nm with a maximum at around 455–460 nm. The fluorescence spectrum dynamics is non-exponential and can be described as a superposition of several decay components. These can be different carbon-containing compounds and functional groups, such as OH, C=O, and COOH.

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Section: Resultsmentioning

confidence: 99%

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Chernyakova

Jasulaitienė

Naujokaitis

et al. 2023

J. Electrochem. Soc.

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“…From the substrates, square samples with an area of no more than 7.2 cm 2 were cut and anodized in a 0.3 M aqueous solution of oxalic acid at constant U a = 30 V and T e = 5 °С-40 °С until the complete oxidation of aluminum. The anodizing process was carried out in a two-electrode fluoroplastic cell similar to that described by Chernyakova et al 22 and was controlled by a direct current power supply GW Instek (GPR-30H100). A Viton O-ring set out the anodizing area of ca.…”

Section: Methodsmentioning

confidence: 99%

“…According to Chernyakova et al, 22 to provide a more uniform temperature distribution over the surface of the working electrode at different anodizing modes and correspondingly greater pore ordering, we chose a SiO 2 /Si substrate because of its higher thermal conductivity (149 W m −1 K −1 ) close to that of aluminum (200 W m −1 K −1 ). The anodizing voltage was also selected according to Chernyakova et al 22 as, during the oxidation of aluminum thin films in oxalic acid, U a of 30 V is a turning point at which the mechanism of the formation of porous anodic structure is changed.…”

Section: Methodsmentioning

confidence: 99%

Influence of Induced Local Stress on The Morphology of Porous Anodic Alumina at The Initial Stage of Oxide Growth

Chernyakova,

Tzaneva,

Jagminas

et al. 2023

J. Electrochem. Soc.

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A characteristic feature of the disordered pore growth at the initial stage of aluminum anodizing is the development of three large groups of pores: the major pores of larger diameter and two groups of minor pores of smaller diameter. The samples were obtained by the electrochemical oxidation of thin aluminum films (100 nm thick) on SiO2/Si substrates in a 0.3 M oxalic acid at 30 V at 5–40 °C. According to SEM studies, the pore distribution by diameter for the films obtained at 20 and 40 °C has three distinct peaks at ca. 13.5, 17.2, and 20.3 nm. The ratio of the diameter of major pores to the diameter of minor pores of group 1 or group 2 is constant and approximately equal to 1.17 and 1.51, respectively. The generation of local compressive stress influences the development of porous morphology. The distribution of zones with high and low compressive stress levels inside hexagonal cells is shown, and their correlation with the porous morphology is confirmed. The generation of local stress and strains in the anodic alumina layer with a porous, cellular structure is associated with local areas with changes in the geometric properties on its surface.

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“…The first successful demonstration of this principle was reported for the similar anodic aluminum oxide (AAO) system to grow ordered structures at rates approaching 10 4 nm min −1 [15,16] . These “hard anodization” processes, however, are accompanied by intense temperature surges due to Joule heating [17,18] . Left unaddressed, localized high current regions in the oxide film generate drastic temperature gradients, current channeling, and film breakdown – known as oxide burning [19–22] .…”

Section: Introductionmentioning

confidence: 99%

“…[15,16] These "hard anodization" processes, however, are accompanied by intense temperature surges due to Joule heating. [17,18] Left unaddressed, localized high current regions in the oxide film generate drastic temperature gradients, current channeling, and film breakdown -known as oxide burning. [19][20][21][22] To overcome this, pulse anodization techniques, in which the induced current density oscillates between "mild" and hard conditions (e. g., ~3 and 370 mA cm À 2 , respectively) were developed to permit intermittent heat dissipation.…”

Section: Introductionmentioning

confidence: 99%

A Simple and Rapid Method of Forming Double‐Sided TiO₂ Nanotube Arrays

et al. 2022

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Highly ordered TiO 2 nanostructures, known as nanotube arrays (NTAs), exhibit potential in various energy, chemical sensing, and biomedical applications. Owing to its simplicity and high degree of control, titanium anodization serves as the prevailing NTA synthesis method. However, the practicality of this approach is marred by sluggish and inconsistent growth rates, on the order of 10 nm min À 1 . Growth rates strongly depend on the electrolyte conductivity, yet most reports neglect to consider this property as a measured and controllable parameter. Here, we have systematically determined a broad set of conditions (at 60 V applied potential, elevated temperatures) that allow researchers to fabricate NTAs quickly and simply. By modulating conductivity through variation of bulk electrolyte temperature and the controlled addition of several hydroxy acid species, we achieve consistent accelerated growth up to 10 times faster than traditional methods. We find that regulating the solution conductivity within a desired region (e. g., ~800-1000 μS cm À 1 ) enabled the fabrication of double-sided NTA layers of around 10 μm and 90 μm NTA in 10 and 180 min, respectively.6 hours to synthesize, [12,13] while NTAs desired for membranes may take on the order of days (Figure 1, Table S1). [14] Expediting this process is not only appealing at the applied research level, but could be essential if many proposed applications were to reach the stage of high-throughput testing.Accelerating NTA growth requires increasing the rate of the associated etching reactions (typically by increasing the applied potential, Figure S3), although this approach often comes at the risk of material damage. The first successful demonstration of this principle was reported for the similar [a] C.

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Effect of Joule Heating on Formation of Porous Structure of Thin Oxalic Acid Anodic Alumina Films

Cited by 18 publications

References 34 publications

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Influence of Induced Local Stress on The Morphology of Porous Anodic Alumina at The Initial Stage of Oxide Growth

A Simple and Rapid Method of Forming Double‐Sided TiO₂ Nanotube Arrays

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Effect of Joule Heating on Formation of Porous Structure of Thin Oxalic Acid Anodic Alumina Films

Cited by 18 publications

References 34 publications

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Influence of Induced Local Stress on The Morphology of Porous Anodic Alumina at The Initial Stage of Oxide Growth

A Simple and Rapid Method of Forming Double‐Sided TiO2 Nanotube Arrays

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A Simple and Rapid Method of Forming Double‐Sided TiO₂ Nanotube Arrays