Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution
The fast and sharp corrosion potential change from the active state to the passive state, that pure zinc plates immersed in calcium hydroxide saturated solutions with and without chlorides spontaneously exhibit at the early stage of passivation, was studied. The corrosion behavior was investigated b...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-06-01
|
| Series: | Frontiers in Materials |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmats.2022.877728/full |
| _version_ | 1811238550247571456 |
|---|---|
| author | Armando Garnica-Rodríguez R. Montoya Francisco Javier Rodríguez-Gomez Tezozomoc Pérez-López Juan Genesca |
| author_facet | Armando Garnica-Rodríguez R. Montoya Francisco Javier Rodríguez-Gomez Tezozomoc Pérez-López Juan Genesca |
| author_sort | Armando Garnica-Rodríguez |
| collection | DOAJ |
| description | The fast and sharp corrosion potential change from the active state to the passive state, that pure zinc plates immersed in calcium hydroxide saturated solutions with and without chlorides spontaneously exhibit at the early stage of passivation, was studied. The corrosion behavior was investigated by corrosion potential monitoring, anodic polarization curves and electrochemical impedance spectroscopy. The zinc surface was characterized by scanning electron microscopy and X-ray energy dispersive spectroscopy. Experimental results show that the presence of chlorides increases the rate of change of potential by 10-fold in the early stage of passivation, producing a porous passivating film of corrosion products mainly made of calcium hydroxy-zincate Ca(Zn(OH)3)2· 2 H2O, with a less protective barrier effect than the non-porous film formed without chlorides. On the other hand, a modeling approach was achieved by solving the transient 2D Nernst–Planck equations and considering 12 chemical species. Numerical results confirm that the composition of the chemical products generated on the Zn surface certainly depends on the concentration of Cl¯ ions: Simonkolleite and hidroxides become unstable in the presence of high Cl¯ concentrations, whereas calcium hydroxyl-zincate is the main chemical compound generated on the Zn surface. However, the presence of the latter compound is much more important in electrolytes with very low concentration of Cl¯ ions. |
| first_indexed | 2024-04-12T12:44:01Z |
| format | Article |
| id | doaj.art-1384fe09b0d94ae9b1d820ea459ed24d |
| institution | Directory Open Access Journal |
| issn | 2296-8016 |
| language | English |
| last_indexed | 2024-04-12T12:44:01Z |
| publishDate | 2022-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Materials |
| spelling | doaj.art-1384fe09b0d94ae9b1d820ea459ed24d2022-12-22T03:32:41ZengFrontiers Media S.A.Frontiers in Materials2296-80162022-06-01910.3389/fmats.2022.877728877728Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide SolutionArmando Garnica-Rodríguez0R. Montoya1Francisco Javier Rodríguez-Gomez2Tezozomoc Pérez-López3Juan Genesca4Departamento de Ingeniería Metalúrgica, Facultad de Química, Universidad Nacional Autónoma de México, México City, MexicoPolo Universitario de Tecnología Avanzada, PUNTA, Facultad Química, UNAM, Apodaca, MexicoDepartamento de Ingeniería Metalúrgica, Facultad de Química, Universidad Nacional Autónoma de México, México City, MexicoCentro de Investigación en Corrosión, Universidad Autónoma de Campeche, Campeche, MexicoPolo Universitario de Tecnología Avanzada, PUNTA, Facultad Química, UNAM, Apodaca, MexicoThe fast and sharp corrosion potential change from the active state to the passive state, that pure zinc plates immersed in calcium hydroxide saturated solutions with and without chlorides spontaneously exhibit at the early stage of passivation, was studied. The corrosion behavior was investigated by corrosion potential monitoring, anodic polarization curves and electrochemical impedance spectroscopy. The zinc surface was characterized by scanning electron microscopy and X-ray energy dispersive spectroscopy. Experimental results show that the presence of chlorides increases the rate of change of potential by 10-fold in the early stage of passivation, producing a porous passivating film of corrosion products mainly made of calcium hydroxy-zincate Ca(Zn(OH)3)2· 2 H2O, with a less protective barrier effect than the non-porous film formed without chlorides. On the other hand, a modeling approach was achieved by solving the transient 2D Nernst–Planck equations and considering 12 chemical species. Numerical results confirm that the composition of the chemical products generated on the Zn surface certainly depends on the concentration of Cl¯ ions: Simonkolleite and hidroxides become unstable in the presence of high Cl¯ concentrations, whereas calcium hydroxyl-zincate is the main chemical compound generated on the Zn surface. However, the presence of the latter compound is much more important in electrolytes with very low concentration of Cl¯ ions.https://www.frontiersin.org/articles/10.3389/fmats.2022.877728/fullEISgalvanizedconcretezinc passivationfast potential changemodeling |
| spellingShingle | Armando Garnica-Rodríguez R. Montoya Francisco Javier Rodríguez-Gomez Tezozomoc Pérez-López Juan Genesca Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution Frontiers in Materials EIS galvanized concrete zinc passivation fast potential change modeling |
| title | Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution |
| title_full | Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution |
| title_fullStr | Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution |
| title_full_unstemmed | Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution |
| title_short | Effect of a Fast Potential Change on the Early Stage of Zinc Passivation in a Saturated Calcium Hydroxide Solution |
| title_sort | effect of a fast potential change on the early stage of zinc passivation in a saturated calcium hydroxide solution |
| topic | EIS galvanized concrete zinc passivation fast potential change modeling |
| url | https://www.frontiersin.org/articles/10.3389/fmats.2022.877728/full |
| work_keys_str_mv | AT armandogarnicarodriguez effectofafastpotentialchangeontheearlystageofzincpassivationinasaturatedcalciumhydroxidesolution AT rmontoya effectofafastpotentialchangeontheearlystageofzincpassivationinasaturatedcalciumhydroxidesolution AT franciscojavierrodriguezgomez effectofafastpotentialchangeontheearlystageofzincpassivationinasaturatedcalciumhydroxidesolution AT tezozomocperezlopez effectofafastpotentialchangeontheearlystageofzincpassivationinasaturatedcalciumhydroxidesolution AT juangenesca effectofafastpotentialchangeontheearlystageofzincpassivationinasaturatedcalciumhydroxidesolution |