Galvanic corrosion of magnesium alloy AZ91D in contact with an aluminium alloy, steel and zinc

Song, Guang‐Ling; Jóhannesson, Birgir; Hapugoda, Sarath; StJohn, David H.

doi:10.1016/s0010-938x(03)00190-2

Cited by 312 publications

(157 citation statements)

References 28 publications

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“…Most work about galvanic corrosion is conducted using dissimilar metals which are connected via mechanical 'bonding' or through wires [103,104]. The mechanically 'bonded' samples are obtained through rolling or other mechanical methods.…”

Section: Research Outlook On Localized Galvanic Corrosion Arising Betmentioning

confidence: 99%

A Summary of Corrosion Properties of Al-Rich Solid Solution and Secondary Phase Particles in Al Alloys

Dang

2017

Metals

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Abstract:The heterogeneous structure of Al alloys renders them susceptible to localized corrosion due to the different electrochemical properties existing in the Al-rich solid solution matrix and secondary phase particles. The galvanic interactions between these two phases can result in pit formation either through dissolution of the particles or corrosion of the matrix adjacent to the particles. This detrimentally localized corrosion behavior is closely related to the corrosion properties of the particles and the Al-rich matrix. The comprehensive characterization of this behavior under various and varying conditions is critical to understanding the mechanism of pit formation, selecting appropriate inhibitors, and developing protection strategies. The corrosion properties (corrosion potential, pitting potential and corrosion rate) of both secondary phase particles and Al-solid solutions in Al alloys are summarized in this review, aiming to provide a database for corrosion research applicable to the localized corrosion of Al alloys.

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Section: Research Outlook On Localized Galvanic Corrosion Arising Betmentioning

confidence: 99%

A Summary of Corrosion Properties of Al-Rich Solid Solution and Secondary Phase Particles in Al Alloys

Dang

2017

Metals

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“…A smaller anodic surface area leads to a more intense and localized attack. [148] Similarly, in case of nanocrystalline materials, the larger anodic area (due to high grain boundary area fraction) leads to increase in the anode-cathode area ratio as compared to microcrystalline alloys, which results in dissipation of localized attack by aggressive ions. (b) Certain impurities enhance the anodic behavior of grain boundaries.…”

Section: Electrochemical Characteristic Of Grain Boundariesmentioning

confidence: 99%

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Mahesh

Raman

2014

Metall Mater Trans A

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The extremely fine grain size of nanocrystalline (nc) metallic alloys results in significantly different mechanical, electrochemical and oxidation properties as compared to the coarse-grained alloys of the same composition. Although the synthesis and attractive mechanical properties of nanocrystalline materials have been investigated and reviewed in great depth, the high temperature oxidation and electrochemical corrosion of these materials has received limited attention. The difference in the active dissolution and passivation behavior of nc alloys as compared to their microcrystalline counterparts varies for each alloy system. However, a unified theory explaining these phenomena still eludes us. In this context, this article reviews the progress in the electrochemical corrosion behavior of different nanocrystalline alloys, and hence, develops a better understanding of the effect of grain size, composition, interfacial phenomena and selective dissolution on corrosion of nanocrystalline alloys. This review also presents the role of nanometric grain size and the associated increase in grain boundary diffusion on the high temperature oxidation of nc alloys. The attractive possibility of enhanced oxidation resistance at lower alloying additions as compared to the coarse-grained alloys has been discussed. Although the primary focus of the article is on ferrous alloy systems, however, the lead studies on the role of ultrafine grain size in oxidation/corrosion behavior of other alloys systems have also been reviewed.

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“…The different affinities of anodes and cathodes to the corrosion create an electrical potential between them and consequently the anodes (UFG matrix) undergo the corrosion with a higher rate than that of the plain UFG sample. It is known that this accelerated corrosion is beneficial for the metals capable of being passivated [64]. The migration of Al ions through the passive layer and its consequent thickening as well as the reduction of oxygen over the cathodic regions are the main processes which occur in the bimodal samples.…”

Section: Discussionmentioning

confidence: 99%

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Oskooie

Asgharzadeh

Sadighikia

et al. 2016

Metals

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Abstract:The bimodal microstructures of Al6063 consisting of 15, 30, and 45 vol. % coarse-grained (CG) bands within the ultrafine-grained (UFG) matrix were synthesized via blending of high-energy mechanically milled powders with unmilled powders followed by hot powder extrusion. The corrosion behavior of the bimodal specimens was assessed by means of polarization, steady-state cyclic polarization and impedance tests, whereas their microstructural features and corrosion products were examined using optical microscopy (OM), scanning transmission electron microscopy (STEM), field emission scanning electron microscopy (FE-SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques. The bimodal Al6063 containing 15 vol. % CG phase exhibits the highest corrosion resistance among the bimodal microstructures and even superior electrochemical behavior compared with the plain UFG and CG materials in the 3.5% NaCl solution. The enhanced corrosion resistance is attributed to the optimum cathode to anode surface area ratio that gives rise to the formation of an effective galvanic couple between CG areas and the UFG matrix. The operational galvanic coupling leads to the domination of a "self-anodic protection system" on bimodal microstructure and consequently forms a uniform thick protective passive layer over it. In contrast, the 45 vol. % CG bimodal specimen shows the least corrosion resistance due to the catastrophic galvanic corrosion in UFG regions. The observed results for UFG Al6063 suggest that metallurgical tailoring of the grain structure in terms of bimodal microstructures leads to simultaneous enhancement in the electrochemical behavior and mechanical properties of passivable alloys that are usually inversely correlated. The mechanism of self-anodic protection for passivable metals with bimodal microstructures is discussed here for the first time.

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Galvanic corrosion of magnesium alloy AZ91D in contact with an aluminium alloy, steel and zinc

Cited by 312 publications

References 28 publications

A Summary of Corrosion Properties of Al-Rich Solid Solution and Secondary Phase Particles in Al Alloys

A Summary of Corrosion Properties of Al-Rich Solid Solution and Secondary Phase Particles in Al Alloys

Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

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