Galvanic corrosion of Ti6Al4V -AA2024 joints in aircraft environment: Modelling and experimental validation

Snihirova, Darya; Höche, Daniel; Lamaka, Sviatlana V.; Mir, Zahid; Hack, T.; Zheludkevich, Mikhail L.

doi:10.1016/j.corsci.2019.04.036

Cited by 62 publications

(23 citation statements)

References 40 publications

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“…Having a validated computational model allows focusing of experiments in the most important parts of parameter space (explored more in Part 2). Therefore, finite element modeling has become a common approach to study the effects of galvanic coupling, through the utilization of both the Laplace equation, [4][5][6][7][8][9][10][11][12] and the Nernst-Planck equation. 4,[13][14][15][16] A thorough discussion on both approaches was recently published by Liu and Kelly, 17 however, this work will only focus on a Laplacian-based model.…”

Section: Introductionmentioning

confidence: 99%

“…Much modeling research has been done on the galvanic coupling of dissimilar metals in simple geometries. [4][5][6]9,14,18 However, less modeling research has been done on more complex geometries, such as panel/fastener assemblies, 8,[11][12][19][20] which are more common in real-life situations and are known to trap water in crevices between dissimilar metals. [21][22] The complex geometry of structural components in the aircraft increases the difficulty in both experimental measurement and modeling of the galvanic couple.…”

Section: Introductionmentioning

confidence: 99%

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Galvanic Corrosion Between Coated Al Alloy Plate and Stainless Steel Fasteners, Part 1: FEM Model Development and Validation

et al. 2019

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Aerospace structures often involve dissimilar materials to optimize structural performance and cost. These materials can then lead to the formation of galvanic couples when moisture is present. Specifically, noble metal fasteners (such as SS316) are often used in aluminum alloy load-bearing structures, which can lead to accelerated, localized corrosion attack of the aluminum alloy due to the cathodic current supplied by the SS316 fastener. This localized attack is difficult to predict, and tests are often expensive, so modeling of these galvanic couples could be of great utility. The work reported here focuses on the galvanic coupling between fasteners installed in a panel test assembly, and the resultant corrosion damage down the fastener holes. This arrangement is a common assembly geometry in aerospace applications. A specific sol-gel coating was applied to the fasteners, to determine its effectiveness on mitigating galvanic corrosion; bare fasteners were also tested, to investigate a worst-case scenario. Geometric constraints in the model were made to match those of an experimental test panel, which was exposed to ASTM B117 salt fog for 504 h. The electrochemical boundary conditions were generated in solutions appropriate to the material and environment to which it would be exposed. Anodic charge passed during exposure was calculated from image analyses of the corrosion damage in the experimental test, and the results were compared with the model. The Laplacian-based model provides a very good first approximation for predicting the damage within the fastener hole. Validation was provided by both experimental results generated in this study as well as comparison to results in the literature that used similar, but not identical, conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Galvanic Corrosion Between Coated Al Alloy Plate and Stainless Steel Fasteners, Part 1: FEM Model Development and Validation

et al. 2019

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“…On short time and length scales, microscopic models (incl. electronic and atomistic models) are often employed to compute the initiation stage, and the reaction rates and migration processes of the participating chemical species . While this approach allows to accurately model the creation and the influence of corrosion products, it is computationally expensive.…”

Section: Introductionmentioning

confidence: 99%

Enhanced predictive corrosion modeling with implicit corrosion products

Gießgen

Mittelbach

Höche

et al. 2019

Materials & Corrosion

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An advanced mathematical approach to describe the influence of corrosion products on the corrosion rate is presented here. The related model can be used as input equation for numerical predictive corrosion simulations or simply as an empirical model, to extrapolate experimental data of corrosion tests to longer times and to interpret the physical parameters behind. This semiempirical model assumes that a constant share of the dissolved metal precipitates on the surface and hinders the diffusion processes. Hence, the effective corrosion rate decreases exponentially with increasing dissolution. The explicit corrosion progress over time is derived by time integration on a newly developed, time dependent corrosion rate equation. The derived expression can be effortlessly implemented in existing for example finite element method, which is demonstrated for the uniform corrosion of a zinc surface. Furthermore, this approach is qualitatively compared with other empirical models for corrosion products and the validity is demonstrated by fitting of experimental data. A very good agreement between experiment and theory can be achieved for various materials and environments considering no change of the driving corrosion mechanism.K E Y W O R D S corrosion products, corrosion simulation, finite element method, mixed potential theory, uniform corrosion

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“…The local gradient of dissolved oxygen over the corroding Mg surface was measured with a fiber-optic micro-optode (O 2 probe) simultaneously with pH monitoring in order to accurately investigate the influence of additives on Mg self-corrosion. The simultaneous measurements of the local pH and the concentration of dissolved oxygen were successfully demonstrated in the field of corrosion science. − In this study, the measurements of O 2 and pH were assessed during discharge. The experimental details are given in the Supporting Information.…”

mentioning

confidence: 99%

“…However, the ratio between two cathodic processes (eqs 1 and 3) is hard to establish. Since the oxygen reduction on the Mg surface is faster than the rate of oxygen diffusion from the bulk electrolyte to the metal surface (DO 2 = 2.4 × 10 −9 m 2 s −1 ), 30 we assume that under discharge conditions the contribution of oxygen reduction to the cathodic process would play a minor role.…”

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confidence: 99%

Synergistic Mixture of Electrolyte Additives: A Route to a High-Efficiency Mg–Air Battery

Snihirova

Wang

Lamaka

et al. 2020

J. Phys. Chem. Lett.

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Magnesium primary cells are currently experiencing a renaissance following the suggestion of new strategies to boost their performance. The strategies suggested will maintain utilization efficiencies of 30–70%, which is considered to be relatively modest. In this work, the highest ever reported level of utilization efficiency of 82% is achieved for a Mg-based primary cell using a synergistic combination of electrolyte additives. It is demonstrated that the joint use of sodium nitrate and salicylate as electrolyte additives allows us to reach the aforementioned utilization efficiency of 5 mA/cm2 via offering an effective suppression of anode self-corrosion and uniform Mg dissolution under discharge conditions.

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Galvanic corrosion of Ti6Al4V -AA2024 joints in aircraft environment: Modelling and experimental validation

Cited by 62 publications

References 40 publications

Galvanic Corrosion Between Coated Al Alloy Plate and Stainless Steel Fasteners, Part 1: FEM Model Development and Validation

Galvanic Corrosion Between Coated Al Alloy Plate and Stainless Steel Fasteners, Part 1: FEM Model Development and Validation

Enhanced predictive corrosion modeling with implicit corrosion products

Synergistic Mixture of Electrolyte Additives: A Route to a High-Efficiency Mg–Air Battery

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