Corrosion mechanism of model zinc–magnesium alloys in atmospheric conditions

Prošek, Tomáš; Назаров, А. Д.; Bexell, Ulf; Thierry, Dominique; Šerák, Jan

doi:10.1016/j.corsci.2008.06.008

Cited by 279 publications

(170 citation statements)

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“…Figure 11a presents FTIR-ATR spectra obtained on Zn-5Al in air and low CO 2 atmosphere while reference spectra for Zn and Zn-Al compounds are shown in Figure 11b. In air, the main corrosion products on these coatings are zinc hydroxy chloride, Zn 5 (OH) 8 which have a characteristic band at 1360 cm −1 due to carbonate ions. However, it cannot be ruled out that small amounts of this compound are formed also on Zn-0.2Al.…”

Section: Resultsmentioning

confidence: 99%

“…This compound is formed after anodic dissolution of zinc in these areas and migration of chlorides and hydroxyl ions to these locations. While the formation of Zn(OH) 2 / ZnO might occur at the anodic areas, these are transformed to Zn 5 (OH) 8 Cl 2 · H 2 O when the pH is lowered in these areas. Carbonate is formed at cathodic sites from carbon dioxide, which leads to the formation of Zn 5 (OH) 6 (CO 3 ) 2 at the cathodic areas.…”

Section: Discussionmentioning

confidence: 99%

“…40 Schematic reaction sequences for the formation of corrosion products on Zn-0.2Al are shown in Figure 13a. Zinc hydroxy chloride such as Zn 5 (OH) 8 Cl 2 · H 2 O is formed primarily in connection with the anodic areas on the samples. This compound is formed after anodic dissolution of zinc in these areas and migration of chlorides and hydroxyl ions to these locations.…”

Section: Discussionmentioning

confidence: 99%

“…It is known that the formation of ZnO is favored at high pH values and low CO 2 content, while Zn 5 (OH) 6 (CO 3 ) 2 is formed at higher CO 2 content. 38 Simonkolleite, Zn 5 (OH) 8 Cl 2 · H 2 O is formed preferentially at low pH and at high concentrations of chloride. The solubility of the LDH, Zn 3 Al(OH) 8 (CO 3 ) 1/2 · xH 2 O was studied by Johnson and Glasser.…”

Section: Discussionmentioning

confidence: 99%

“…typically 1 to 4 wt% of magnesium and aluminum), showing better corrosion properties than HDG, have been developed for continuous galvanized steel sheet. [4][5][6][7][8][9][10][11][12][13] From the extensive literature on the atmospheric corrosion of zinc in field exposures and laboratory tests, [14][15][16][17][18][19][20][21][22][23] zinc is indeed well known to be highly affected by chloride and sulfur dioxide in particular. The level of CO 2 in the atmosphere has also been reported to have a noticeable influence on the corrosion of zinc [24][25][26][27] and zinc coatings including HDG, Zn-5Al and Zn-Al-Mg (ZM).…”

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Atmospheric Corrosion of Zinc-Aluminum Alloyed Coated Steel in Depleted Carbon Dioxide Environments

LeBozec

Thierry

Persson

et al. 2018

J. Electrochem. Soc.

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NaCl induced corrosion of Zn-0.2Al, Zn-5Al and Zn-55Al coated steel was investigated at low and ambient CO 2 levels. Weight loss measurements revealed an enhancement of the corrosion of Zn-0.2Al and particularly Zn-5Al in low CO 2 . This was connected to an increase of surface pH in a low CO 2 atmosphere promoting the formation of ZnO and layered double hydroxide for Zn-5Al. For Zn-55Al, CO 2 depletion did not affect the surface pH due to the acidification effect of Al 3+ . Preferential dissolution of zinc rich phase was observed on cross-sections, particularly in depleted CO 2 experiments. Different sequences of corrosion product formation were proposed for the different Zn-Al coatings. Among Zn-Al coated steels, which are widely used in the construction industry as a better corrosion resistant alternative to replace hot-dip galvanized steel (HDG), two main compositions may be found i.e. Galfan containing 5% aluminum (Zn-5Al) and Galvalume containing 55% aluminum and about 1.6% Si (Zn-55Al). These Zn-Al coatings indeed present a better corrosion performance than HDG in marine and industrial atmospheres, where the main corrosive elements are chloride from seawater aerosols and sulfur dioxide from fume emissions. 1-3 The corrosion rate upon long term field exposure was generally 1.5 to 2 and 2 to 4 times lower than that of HDG for Zn-5Al and Zn-55Al, respectively. Hydrotalcite compounds identified in the corrosion products are believed to play an important role in the corrosion protection. Their formation in the interdendritic areas of Zn-55Al blocks the cathodic reaction because of their inability to act as cathodes, and thus, the overall corrosion rate should decrease.More recently, new zinc coatings alloyed with aluminum and magnesium (i.e. typically 1 to 4 wt% of magnesium and aluminum), showing better corrosion properties than HDG, have been developed for continuous galvanized steel sheet. [4][5][6][7][8][9][10][11][12][13] From the extensive literature on the atmospheric corrosion of zinc in field exposures and laboratory tests, [14][15][16][17][18][19][20][21][22][23] zinc is indeed well known to be highly affected by chloride and sulfur dioxide in particular. The level of CO 2 in the atmosphere has also been reported to have a noticeable influence on the corrosion of zinc 24-27 and zinc coatings including HDG, Zn-5Al and Zn-Al-Mg (ZM). 28 Thus, an enhancement of the corrosion of zinc and zinc coated steel has been observed in depleted CO 2 conditions, which may be achieved in confined situations or under paints for example. Such results were also observed on aluminum and aluminum alloys, 26 as well as on magnesium and magnesium alloys. [29][30][31] Whilst the corrosion performance of Zn-5Al and ZM coated steel is always superior to HDG in chloride containing environments, the situation is opposite in low CO 2 atmosphere, presumably due to the rather high pH of the surface, which induces a more rapid dissolution of zinc and the aluminum phases. 28 In the present study, the aim was to examine the effect of ...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Atmospheric Corrosion of Zinc-Aluminum Alloyed Coated Steel in Depleted Carbon Dioxide Environments

LeBozec

Thierry

Persson

et al. 2018

J. Electrochem. Soc.

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Graphene Coatings for the Corrosion Protection of Base Metals

Dennis

Fleer

Davidson

et al. 2016

Graphene Technology: From Laboratory to Fabrication

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Influence of the Surface and Heat Treatment on the Bond Strength of Galvanized Steel/Aluminum Composites Joined by Plastic Deformation

et al. 2016

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The influence of a chemical or mechanical surface modification followed by different post-heat treatments on the bond strength of galvanized steel/aluminum composites is studied. An incremental rolling process is used for joint formation based on plastic deformation. The morphology, the chemical state of the modified surfaces as well as the cross-section, and local potential distribution of the welded zone is characterized by different microscopic and spectroscopic methods. The stability of the joint is analyzed by a shear-force test in combination with microscopic failure analysis. A clear correlation between pre/post-treatment and the joint strength is observed. 1709/16-2, HO 2356/8-2, and MA 1175/36-2 as part of the ECUF project (SPP 1640 framework). Special thanks are due to N. Buitkamp (CMP) for supplying the FE-SEM measurements.

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Corrosion mechanism of model zinc–magnesium alloys in atmospheric conditions

Cited by 279 publications

References 18 publications

Atmospheric Corrosion of Zinc-Aluminum Alloyed Coated Steel in Depleted Carbon Dioxide Environments

Atmospheric Corrosion of Zinc-Aluminum Alloyed Coated Steel in Depleted Carbon Dioxide Environments

Graphene Coatings for the Corrosion Protection of Base Metals

Influence of the Surface and Heat Treatment on the Bond Strength of Galvanized Steel/Aluminum Composites Joined by Plastic Deformation

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