The corrosion of magnesium in aqueous solution containing chloride ions

Tunold, R.; Holtan, Hans; Berge, May-Britt Hägg; Lasson, Axel; Steen-Hansen, Rolf

doi:10.1016/0010-938x(77)90059-2

Cited by 173 publications

(139 citation statements)

References 30 publications

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“…The reaction of the Mg-Ti-Ni-Au particles can be observed from the evolution of a clear bubble tail even in the 0.001 M sodium chloride media, reecting the strong pitting corrosion effect of the chloride ions. As expected, 31 higher chloride concentrations induce faster reaction rates. For example, the micromotors display an efficient speed of 90 mm s À1 in 0.3 M sodium chloride (b), and an even higher speed of 300 mm s À1 in 3 M sodium chloride (c).…”

supporting

confidence: 81%

“…Pitting corrosion commonly occurs in metals that are protected by a passivation layer (e.g., Mg with a Mg(OH) 2 layer). [29][30][31][32] It is well known that chloride ions promote the corrosion of Mg in aqueous solutions. 31 Aggressive anionic species, such as chloride, are able to penetrate the passivation layer and are further electrostatically transported into the pit, where they serve to balance the charge within the corrosion pits as the Mg + cation concentration builds up.…”

mentioning

confidence: 99%

“…[29][30][31][32] It is well known that chloride ions promote the corrosion of Mg in aqueous solutions. 31 Aggressive anionic species, such as chloride, are able to penetrate the passivation layer and are further electrostatically transported into the pit, where they serve to balance the charge within the corrosion pits as the Mg + cation concentration builds up. 27,29 As the Mg corrosion continues, the OH À is depleted within the pit, preventing the passivation of the pit surfaces.…”

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Seawater-driven magnesium based Janus micromotors for environmental remediation

et al. 2013

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We describe the use of seawater as fuel to propel Janus micromotors.The new micromotors consist of biodegradable and environmentally friendly magnesium microparticles and a nickel-gold bilayer patch for magnetic guidance and surface modification. Such seawaterdriven micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, eliminate the need for external fuels to offer efficient and prolonged propulsion towards diverse applications in aquatic environments.The propulsion of synthetic nanoscale objects represents a great challenge and opportunity, and has thus stimulated considerable research efforts in recent years. 1-10 Self-propelled micromotors offer promise for diverse practical applications, such as drug delivery, 11,12 biomaterials isolation, 13-15 surface patterning 16 and environmental remediation. 17 Bubblepropelled catalytic micromotors are particularly attractive due to their efficient propulsion in relevant biological uids and high ionic-strength media. 18-21 Unfortunately, the requirement of the hydrogen peroxide fuel greatly impedes many practical applications of such catalytic micro/nanoscale motors. 7 New micro/nanomotors that can harvest energy from their own surrounding environment, i.e., use the sample matrix itself as their fuel source, are highly desired for eliminating the need for adding external fuels. For example, Gao et al. illustrated hydrogen-bubble-propelled micromotors that can be powered in acidic or alkaline media. 22,23 However, water is the obvious ideal choice of fuel for the majority of practical nanomachine applications compared to extreme acidic or alkaline media. Recently we described the rst example of a water-driven micromotor, based on Al/Ga microparticles, which displayed efficient propulsion in aqueous solutions. 24 However, due to the toxicity of aluminum and gallium, more biocompatible and environmentally friendly materials are highly desired for different applications of water-driven micromotors.Here we demonstrate a new hydrogen-bubble-propelled Janus micromotor, based on the magnesium-water reaction, which can be self-propelled in seawater without an external fuel. Common active metals (e.g., Li, Na, K, Ca), can lead to efficient hydrogen evolution from the water-metal reaction, but are too reactive for a safe operation and are not stable in air. Magnesium, in contrast, is an attractive candidate material for the design of water-driven micromotors as it is a biocompatible 'green' nutrient trace element, vital for many bodily functions and enzymatic processes. In addition, Mg is a low cost metal and Mg 2+ is present in different natural environments (e.g., seawater). The Mg-water reaction is commonly hindered in ambient atmospheres due to the formation of a compact hydroxide passivation surface layer. Accordingly, Mg cannot continuously reduce water to generate hydrogen bubbles. 25,26 However, we demonstrate in the following sections that the micromotor can display efficient and prolonged propulsion in chloride-rich environments ...

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confidence: 99%

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confidence: 99%

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Seawater-driven magnesium based Janus micromotors for environmental remediation

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“…Aggressive ions are expected to damage the surface film. 19 For unbuffered solutions it was shown that the breakdown potential of Mg decreases with increasing chloride concentration 34 and thus film degradation is promoted by Cl − . Furthermore, comparable to most data published on the NDE, 10,14,24 the beaker experiments were steady-state measurements made after considerable periods of polarization during which time both the surface and bulk solution compositions changed.…”

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confidence: 99%

The pH Dependence of Magnesium Dissolution and Hydrogen Evolution during Anodic Polarization

Rossrucker

Samaniego

Grote

et al. 2015

J. Electrochem. Soc.

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The dissolution of magnesium (Mg) has been investigated with an electrochemical flow cell coupled to downstream analysis. The setup allows for polarization experiments and simultaneous determination of the amount of dissolved magnesium ions via inductively coupled plasma -mass spectroscopy (ICP-MS). Additionally, Mg dissolution was compared to hydrogen evolution measurements in the flow cell and also in standard beakers. Experiments were performed in unbuffered NaCl and in buffered solutions of various pH to determine the influence of the pH on surface film stability and Mg dissolution. In borate buffer (pH 10.5), Mg(OH) 2 was found to be more stable than in unbuffered electrolyte. In the flow cell, the negative difference effect (NDE) was absent for low anodic polarization currents in a neutral buffered solution, whilst high anodic polarization currents and unbuffered electrolytes favored its existence. In beaker experiments, strong NDE was observed in a pH 10.5 buffer, and also in pH 7 and 3 buffers, but only at higher applied currents where the buffering capacity was locally overwhelmed. These observations validate the importance of the pH in near surface regions with respect to the stability of Mg-surface films and subsequent NDE.

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“…This phenomenon called "the negative difference effect" (NDE) 9-16 and more recently "the anodic hydrogen evolution" process 17,18 has been also observed for other metals than Mg such as Al, Li. [19][20][21][22] Despite the abundant literature on Mg corrosion and many models of Mg corrosion (such as: the formation of Mg(I) as an intermediate product, 23,24 the formation and breakdown of the partially protective film, 11,[25][26][27] the formation of hydride intermediates, [28][29][30][31][32] formation of dark filiform patterns 13,16 and increase the hydrogen production in aqueous chloride solutions.12,15 Even a very low content of impurities (usually < 150 ppm in "pure" Mg) 41 can lead to formation of such surface film and the morphology of this film depends on electrolyte composition and Cl − concentration. 45,46 The effects of different alloy precipitates and alloy microstructure were widely studied in the case of Mg alloys [47][48][49][50][51][52][53][54][55] but not pure Mg.…”

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Role of Segregated Iron at Grain Boundaries on Mg Corrosion

Mercier

Światowska

Zanna

et al. 2018

J. Electrochem. Soc.

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To elucidate the role of noble metal impurities on corrosion of Mg, 3D time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging in combination with X-ray photoelectron spectroscopy and optical microscopy measurements were carried out on Mg samples (99.9%) before and after Mg polarization at E OCP +0.5 V in 0.1 M NaCl. A significant segregation of Fe (and of Mn and Al) metallic impurities at grain boundaries (GBs) was observed on the Mg surface by 3D ToF-SIMS. A 3-step mechanism of Mg corrosion was proposed, including a catalytic effect of Fe segregated at the GBs on the hydrogen evolution reaction (HER). In the 1 st stage, the initiation of Mg corrosion is accompanied by the HER occurring over Fe impurities segregated at GBs leading to formation of small circular defects, and propagation with occurrence of dark filiform-like pattern corrosion enriched in Cl − . Magnesium and its alloys exhibiting interesting physico-chemical properties such as excellent wide range of mechanical properties at room temperature and low weight (1.7 g.cm −3 ), become good alternatives to aluminum and iron-based alloys in many industrial applications such as automobile, aerospace, energy storage or biomedicine. 1,2Mg and its alloys are spontaneously covered by an oxide/hydroxide layer.3 When exposed to aqueous solution, the oxide layer has a duplex structure consisting of an inner magnesium oxide and an outer porous hydroxide layer 4,5 with a possible presence of magnesium hydride (MgH 2 ).6 At ambient temperature, this oxide layer formed on the Mg (or Mg alloys) surfaces is protective. 1,7 In most aqueous environments (or high humidity) and in a large range of pH, (0-10) as inferred from the potential-pH diagram, this oxide/hydroxide layer is not stable and Mg undergoes dissolution.8 Thus, this is one of the most important limiting factors for applications of Mg and its alloys. Mg dissolution is accompanied by the hydrogen evolution reaction (HER), as the major cathodic reaction. The well-known increase of the HER rate under anodic polarization of Mg seems to be in contradiction with the kinetic models of charge transfer electrochemical reactions (Butler-Volmer equation), predicting that the cathodic current should decrease exponentially with increasing anodic potential. This phenomenon called "the negative difference effect" (NDE) 9-16 and more recently "the anodic hydrogen evolution" process 17,18 has been also observed for other metals than Mg such as Al, Li. [19][20][21][22] Despite the abundant literature on Mg corrosion and many models of Mg corrosion (such as: the formation of Mg(I) as an intermediate product, 23,24 the formation and breakdown of the partially protective film, 11,[25][26][27] the formation of hydride intermediates, [28][29][30][31][32] formation of dark filiform patterns 13,16 and increase the hydrogen production in aqueous chloride solutions.12,15 Even a very low content of impurities (usually < 150 ppm in "pure" Mg) 41 can lead to formation of such surface film and the morphology of this film depen...

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The corrosion of magnesium in aqueous solution containing chloride ions

Cited by 173 publications

References 30 publications

Seawater-driven magnesium based Janus micromotors for environmental remediation

Seawater-driven magnesium based Janus micromotors for environmental remediation

The pH Dependence of Magnesium Dissolution and Hydrogen Evolution during Anodic Polarization

Role of Segregated Iron at Grain Boundaries on Mg Corrosion

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