Influence of geometry on galvanic corrosion of AZ91D coupled to steel

Jia, Jimmy Xueshan; Song, Guang‐Ling; Atrens, Andrej

doi:10.1016/j.corsci.2005.08.013

Cited by 143 publications

(80 citation statements)

References 14 publications

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“…It has been shown that a higher ratio of cathodic-toanodic area, a greater depth of electrolyte solution and a smaller insulating distance between the anode and cathode all result in higher corrosion rates. 14,22 Moreover, the type of metal coupled with Mg also significantly impacts the rate of corrosion. Song et al examined the galvanic coupling of AZ91D with zinc, Al380 and steel, and found that the corrosion rate was significantly higher with steel than with the other two metals.…”

mentioning

confidence: 99%

Hydrogen Evolution during the Corrosion of Galvanically Coupled Magnesium

Banjade

Porter

McMullan

et al. 2016

J. Electrochem. Soc.

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In this study, the impact of galvanic coupling of magnesium to steel on the corrosion rate, surface morphology, and surface film formation was investigated. In particular, experiments were performed to examine and quantify the role of self-corrosion (also called negative difference effect (NDE) or anodic hydrogen) during the corrosion of galvanically coupled Mg. It was found that galvanic coupling at high cathode-to-anode area ratios resulted in high rates of corrosion that impacted hydrogen evolution on the Mg surface. Self-corrosion accounted for, on average, approximately one-third of the total observed corrosion. The self-corrosion fraction varied with time and was found to reach values in excess of 50%. Surface film formation was observed, and approximately 30% of the Mg lost to corrosion was found in the film at the end of our experiments. The surface morphology observed during galvanic corrosion was dramatically different from the filiform structures associated with free corrosion of our samples, but showed similarities to the morphology observed previously for anodically polarized samples. Film formation appeared to slow the rate of self-corrosion with time. These results complement previous studies of Mg corrosion and add important insight into the role of hydrogen evolution on the Mg surface during galvanic corrosion. New environmental regulations, good mechanical properties, abundant availability and reasonable cost have generated renewed interest in the wider use of magnesium (Mg), especially for automobile and aerospace applications.1-4 There has also been growing interest in the use of Mg for batteries and in hydrogen generation systems. 5-8A key obstacle to the use of Mg is its corrosion susceptibility. Consequently, several previous studies have focused on understanding the corrosion mechanisms that control the dissolution rate and surface morphology of Mg during corrosion. Both disk-shaped and filiform corrosion have been observed for unalloyed Mg, depending on the concentration of impurities in the metal and the concentration of Cl − in the electrolyte. [9][10][11] In both cases, the morphology is strongly influenced by the cathodic reaction, which limits the rate of corrosion. 11,12The situation changes dramatically when Mg is coupled to another metal because of the increased cathodic area that significantly diminishes limitations due to the cathodic reaction on the Mg surface. Although most hydrogen evolution occurs on the coupled metal, hydrogen evolution on the Mg surface does not cease. The purpose of this paper is to investigate the impact of galvanic coupling on Mg corrosion that is associated with hydrogen evolution on the Mg surface, and the extent to which such coupling influences both the morphology and rate of Mg self-corrosion.In this paper, we use the term "self-corrosion" to refer to the dissolution of Mg that is not associated with the galvanic current that passes between the coupled metal and the Mg, similar to the definition used previously by others in galvanically coupled st...

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mentioning

confidence: 99%

Hydrogen Evolution during the Corrosion of Galvanically Coupled Magnesium

Banjade

Porter

McMullan

et al. 2016

J. Electrochem. Soc.

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“…[16][17][18] These systems have been solved both analytically 4,8 and numerically. 4,5,7,15,17,19,20 Finding an analytical solution requires making simplifying assumptions such as a 1D-geometry, uniform surface reactivity, and negligible change in solution composition as a result of faradaic reactions. 8 This severely limits the scope of applicable systems.…”

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confidence: 99%

Development of a Model for Experimental Data Treatment of Diffusion and Activation Limited Polarization Curves for Magnesium and Steel Alloys

Stephens

Perry

Gateman

et al. 2017

J. Electrochem. Soc.

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Potentiodynamic polarization curves are often performed to characterize the bulk corrosion properties of a material in terms of its corrosion potential, rate, and Tafel kinetics in a given environment. This requires approaching them as one of two extreme cases, with purely activation or diffusion controlling the measured currents. For the intermediate behavior displayed by many real samples, making this assumption is a significant source of error. In this work, a finite element model has been developed which considers both of these contributions simultaneously for experimental data with a broad material scope. This has been used to examine both extremely corrosion vulnerable samples in two magnesium alloys and extremely corrosion resistant samples in two steels. The effectiveness of several goodness of fit statistics in comparing the similarity between experimental and simulated data has also been assessed.

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“…The galvanic current density should be much higher in the area adjacent to the cathode than in a remote area which induces active sites in the surface of substrate steel. 16,17 Figure 4 show schematic diagram for describing successive mechanism for corrosion and self-healing ability. The corrosion behavior can be divided into three stages.…”

Section: Effect Of Scratching Of Coating Surfacementioning

confidence: 99%

Effect of Scratching of Coating Surface on the Electrochemical Behavior of PVD Al-Mg-Si Coated Steel

et al. 2012

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Effect of scratching of coating surface on the electrochemical behavior of PVD Al-Mg-Si coated steel has been investigated using an open circuit potential (OCP), anodic polarization and galvanic couple test. The OCP monitoring showed a fast ennoblement of OCP then attained a steady state value during the last stage of monitoring. There were two types of corrosion products of scratched coating that protected from continuous corrosion and act as selfhealing. The first is passive film that arises from the adjacent coating surface on both sides of scratched area and covering the underlying steel. The second is corrosion product produced by the corrosion of steel on scratched area.

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Influence of geometry on galvanic corrosion of AZ91D coupled to steel

Cited by 143 publications

References 14 publications

Hydrogen Evolution during the Corrosion of Galvanically Coupled Magnesium

Hydrogen Evolution during the Corrosion of Galvanically Coupled Magnesium

Development of a Model for Experimental Data Treatment of Diffusion and Activation Limited Polarization Curves for Magnesium and Steel Alloys

Effect of Scratching of Coating Surface on the Electrochemical Behavior of PVD Al-Mg-Si Coated Steel

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