A novel approach to determine cathodic passivation characteristics and semiconducting properties of pure aluminium 99.5 wt% and aluminium alloy 7075-T6 with an electrochemical pen electrode

Kroll, R.; Kearns, P.; Usman, Bashir J.; Zhou, Xiaorong; Engelberg, Dirk

doi:10.1016/j.corsci.2022.110898

Cited by 10 publications

(3 citation statements)

References 41 publications

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“…Here, the change transfer resistances (Rct) of the ribbons increase from 1.1 to 2410 kcm 2 with the increase in cCr, indicating that the passivation film becomes more stable and dense, which is consistent with Ref. [65]. Meanwhile, we can see that the value of n ranges from 0.83 to 0.88.…”

Section: 𝑄 𝑗𝜔 / 𝑌supporting

confidence: 87%

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy

Song,

Wang,

Chen

et al. 2023

Materials

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The effect of the Cr element on the corrosion behavior of as-spun Fe72−xCrxB19.2Si4.8Nb4 ribbons with x = 0, 7.2, 21.6, and 36 in 3.5% NaCl solution were investigated in this work. The results show that the glass formability of the alloys can be increased as Cr content (cCr) is added up to 21.6 at.%. When cCr reaches 36 at.%, some nanocrystals appear in the as-spun ribbon. With increasing cCr content, the corrosion resistances of as-spun Fe-based ribbons are continually improved as well as their hardness properties; during the polarization test, their passive film shows an increase first and then a decrease, with the highest pitting potential as cCr = 7.2 at.%, which is confirmed by an XPS test. The dense passivation film, composed of Cr2O3 and [CrOx(OH)3−2x, nH2O], can reduce the number of corrosion pits on the sample surface due to chloride corrosion and possibly be deteriorated by the overdosed CrFeB phase. This work can help us to design and prepare the highly corrosion-resistant Fe-based alloys.

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Section: 𝑄 𝑗𝜔 / 𝑌supporting

confidence: 87%

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy

Song,

Wang,

Chen

et al. 2023

Materials

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“…All of the samples presented a change in the slope at low frequencies, even AA2024 and AA7075, which means that different electrochemical processes occur on the surface, maybe due to heterogeneous anodization. The noise impedance (Zn), also called spectral noise resistance, is expressed by the following equation [43][44][45]: The noise impedance (Z n ), also called spectral noise resistance, is expressed by the following equation [43][44][45]:…”

Section: 𝑙𝑜𝑔ψ = −𝛽 Log 𝑓mentioning

confidence: 99%

“…This energy is called instantaneous energy and it is calculated using an empirical method of decomposition (EMD) to obtain the intrinsic functions (IMF) and to apply an HHT, which was proposed by Huang et al [48] in 1998, to study non-stationary signals, where a spectrum with the distribution of time-frequency energy is generated. It permits the localization of the accumulated energy [44,46,49]. The EMD, proposed by Huang, is expressed in Equation (3):…”

Section: Time-frequency Domain Analysis: Hilbert-huang Transform Anal...mentioning

confidence: 99%

Electrochemical Noise Analysis Using Experimental Chaos Theory, Power Spectral Density and Hilbert–Huang Transform in Anodized Aluminum Alloys in Tartaric–Phosphoric–Sulfuric Acid Solutions

Martínez-Ramos,

Olguin-Coca,

Lopez-Leon

et al. 2023

Metals

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Aluminum and its alloys find widespread applications across diverse industries such as the automotive, construction, and aeronautics industries. When these alloys come into contact with ambient air, an Al2O3 thin oxide layer is naturally formed, typically measuring 2 to 4 nm and exhibiting remarkable hardness and protective qualities, rendering the alloys corrosion-resistant in specific atmospheric and chemical environments. This study aimed to characterize the electrochemical behaviors of anodized AA2024 and AA7075 alloys within a complex three-component electrolyte composed of tartaric–phosphoric–sulfuric acid (TPSA) solutions. The anodized specimens were subsequently exposed to 3.5 wt.% NaCl solution at room temperature, and their electrochemical performances were meticulously evaluated using an electrochemical noise (EN) analysis in accordance with ASTM G-199, respectively. In the EN, three methods of data analysis were used: the time domain analysis (chaos analysis: application of Lyapunov exponent and dimension correlation), the frequency domain analysis (power spectral density, PSD), and the time–frequency domains analysis (Hilbert–Huang transform, HHT). Scanning electron microscopy (SEM) was used to observe the morphologies of the anodized surfaces. The results indicated that the AA2024-0, AA2024-1, and AA2024-2 alloys and the AA7075-2 and AA7075-3 samples exhibited mixed corrosion according to the Lyapunov constant, with a notable inclination towards localized corrosion when analyzed using the PSD and HHT methods. The surface was not homogenous, and the corrosion process was predominately localized in specific zones.

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Passivity breakdown of high-strength 7068 aluminum alloy in borate buffer solutions containing chlorides

Kumar,

Chaudhari

2024

J Solid State Electrochem

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A novel approach to determine cathodic passivation characteristics and semiconducting properties of pure aluminium 99.5 wt% and aluminium alloy 7075-T6 with an electrochemical pen electrode

Cited by 10 publications

References 41 publications

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy

Electrochemical Noise Analysis Using Experimental Chaos Theory, Power Spectral Density and Hilbert–Huang Transform in Anodized Aluminum Alloys in Tartaric–Phosphoric–Sulfuric Acid Solutions

Passivity breakdown of high-strength 7068 aluminum alloy in borate buffer solutions containing chlorides

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