Pitting Corrosion of Zn and Zn-Al Coated Steels in pH 2 to 12 NaCl Solutions

Miao, Wujian; Cole, Ivan; Neufeld, Aaron K; Furman, Scott

doi:10.1149/1.2372691

Cited by 51 publications

(47 citation statements)

References 55 publications

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“…The anodic peak A 1 is characteristic for dissolution and formation of Zn(OH) 2 and ZnO [51,52]. In chloride containing systems, a multilayer structure of the generated film could be present due to coexistence of a number of different species such as Zn 2+ , ZnCl + , Zn(OH) + , Zn 5 OH 8 Cl 2 , (ZnCl 4 ) 2− , ZnCl 2 , Zn(OH) 2 and ZnO [53][54][55].…”

Section: Discussion Of Surface Structure Of Obtained Films and Switchmentioning

confidence: 99%

Electrochemical contrast switching between black and white appearance of gelatin-covered zinc

Ksiazkiewicz¹,

Fernández-Solis²,

Erbe³

2020

J. Phys. Mater.

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Zinc and its alloys are widely used in the surface protection of metallic structural materials. Thus, zinc is an interesting and relevant candidate material for preparing stimuli-responsive surfaces. In this work, the switching of the optical appearance of zinc between black and white by an applied electrode potential is demonstrated. The zinc surface was covered by gelatin films and subjected to cyclic voltammetry (CV) in a chloride-containing electrolyte which induced pitting corrosion on the zinc surface. Between the different parts of the CV cycles, a reversible change in optical appearance was observed. During the oxidative half-cycles, the surfaces appear white, and during the reductive half-cycles, the surfaces appear brown to black, i.e. dark. Surface characterisation by x-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy shows that the gelatin coating is slightly oxidised during intial stages of the process, but remains intact and present at the surface. Raman spectra prove the presence of ZnO at the interface. Surface analysis shows only minor differences in composition between the black and white surfaces. Based on the available characterisation data, the white appearance associated with anodic currents is attributed to the formation of a non-passivating ZnO. The black appearance associated with cathodic currents is attributed to reduction of surface-confined zinc species, including ZnO and Zn 2+ . The role of the gelatin is presumably to prevent diffusion of the dissolution products into solution by complex formation and by acting as a diffusion barrier; gelatin will also affect the morphology of the reduction products. A similar switching was observed when gelatin was added to chloride electrolyte; surface analysis showed gelatin adsorption in this case. The black/white switching may, e.g. be useful for surfaces self-indicating corrosion potentials of galvanised steel.

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Section: Discussion Of Surface Structure Of Obtained Films and Switchmentioning

confidence: 99%

Electrochemical contrast switching between black and white appearance of gelatin-covered zinc

Ksiazkiewicz¹,

Fernández-Solis²,

Erbe³

2020

J. Phys. Mater.

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“…This may be a result of the increased concentration of chloride ions, which are aggressive to the passive layer formed at the anode surface, with respect to hydroxide ions that are inhibitive ions, i.e., lead to the formation of the passive layer [4,17]. Therefore at high concentration of chloride ions, the breakdown of the passive layer is easier and new surface of zinc anode was subjected to dissolution [17]. On the other hand the current efficiency was essentially the same and had a value around 98%, as shown in Fig.…”

Section: Effects Of Simultaneous Application Of Pr Us and Stirringmentioning

confidence: 99%

“…The corrosion and electrochemical studies of zinc dissolution in sodium chloride solutions have been investigated in the literatures [14,[17][18][19]. For pH >12, a passive layer composed of zinc hydroxide and/or zinc oxide is formed on the surface of the zinc sample [19].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyte – A Green Process

Ismail

Abdel-Salam

Ahmed

et al. 2013

Port. Electrochim. Acta

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The anodic dissolution of zinc electrodes in sodium chloride aqueous solution has been investigated experimentally. The effects of application of polarity reversal (PR), ultrasonic (US) enhancement, stirring, current density (CD), concentration and pH of the supporting electrolyte, and temperature of the bath were studied. The results revealed that application of PR increased the dissolution of Zn but the current was low. However, the application of US enhancement led to higher zinc dissolution accompanied with higher current efficiency (CE). The combination of US enhancement and stirring led to more dissolution of zinc. Increasing the current density and concentration of NaCl increased the dissolution of zinc and the current efficiency was almost constant. On the other hand, pH of the bath did not play a significant effect on the amount of the dissolved zinc or current efficiency. It was also observed that increasing the temperature from 10 o C to 40 o C led to a significant increase in the mass of the dissolved zinc and CE; but the increase of temperature from 40 o C to 50 or 60 o C, however, did not have a significant effect.

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“…While a significant body of literature is dedicated to zinc under anodic polarization and/or in alkaline electrolytes, fewer reports have described the cathodic behavior of zinc in near‐neutral solutions . In direct current experiments the latter has been studied potentiodynamically using linear sweep voltammetry at low scan rates (typically around 0.5 to 1 mV/s) that are usually considered to provide “quasi‐steady‐state conditions”.…”

Section: Introductionmentioning

confidence: 99%

Cathodic Corrosion of Zinc under Potentiostatic Conditions in NaCl Solutions

et al. 2018

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Zinc electrodes were polarized cathodically at moderate overpotentials in NaCl 0.6 M solutions under potentiostatic conditions for 7 to 17 hours at room temperature. Corrosion products were characterized by using optical microscopy, XRD, Raman microscopy, XPS, and FIB-SEM. Close to the open-circuit potential, the corrosion products were formed by simonkolleite and the electrochemical response exhibits anodic features. At more negative potentials, the current density remains cathodic throughout the polarization and the deposits on the electrode surface consist almost solely of ZnO. The soluble zinc species necessary for ZnO deposition originate from localized dissolution of the substrate in the form of pits. This effect is assigned to the strong alkalinization of the surface due to oxygen reduction. Despite developing greater surface area than bare zinc substrates, the nanostructured ZnO deposits reduced the cathodic activity.[a] Dr.

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Pitting Corrosion of Zn and Zn-Al Coated Steels in pH 2 to 12 NaCl Solutions

Cited by 51 publications

References 55 publications

Electrochemical contrast switching between black and white appearance of gelatin-covered zinc

Electrochemical contrast switching between black and white appearance of gelatin-covered zinc

Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyte – A Green Process

Cathodic Corrosion of Zinc under Potentiostatic Conditions in NaCl Solutions

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