New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B
In this work, anodic oxide layers on the surface of an AZ31 magnesium alloy were obtained by plasma electrolytic oxidation (PEO) process under low frequency pulsed current. For this, electrolytical solutions containing hexamethylenetetramine and sodium fluoride were used. The morphology and chemical...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Materials Research Express |
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| Online Access: | https://doi.org/10.1088/2053-1591/ab61ac |
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| author | L Toro A A Zuleta E Correa D Calderón Y Galindez J Calderón P Chacón A Valencia-Escobar F Echeverría E |
| author_facet | L Toro A A Zuleta E Correa D Calderón Y Galindez J Calderón P Chacón A Valencia-Escobar F Echeverría E |
| author_sort | L Toro |
| collection | DOAJ |
| description | In this work, anodic oxide layers on the surface of an AZ31 magnesium alloy were obtained by plasma electrolytic oxidation (PEO) process under low frequency pulsed current. For this, electrolytical solutions containing hexamethylenetetramine and sodium fluoride were used. The morphology and chemical composition of formed coatings were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Also, salt spray test, hydrogen evolution and electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy) were conducted in order to study the corrosion behavior of the coated samples. It was found that the use of low frequency pulsed current for the PEO process reduces the film porosity and increases its thickness, compared with PEO films obtained by continuous anodization. The effect of the pulsed current signal was also analyzed for a two steps PEO process, observing changes in the morphological characteristics of the coatings which allow a better corrosion according electrochemical tests (short term corrosion measurements). However, long term tests results as hydrogen evolution and salt spray tests, indicated the opposite. Both the film porosity and thickness were affected by either the pulsing of the current or the use of a two-step process. |
| first_indexed | 2024-03-12T15:47:43Z |
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| id | doaj.art-2f436f4114524697b8654352f3ec844b |
| institution | Directory Open Access Journal |
| issn | 2053-1591 |
| language | English |
| last_indexed | 2024-03-12T15:47:43Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Materials Research Express |
| spelling | doaj.art-2f436f4114524697b8654352f3ec844b2023-08-09T15:20:37ZengIOP PublishingMaterials Research Express2053-15912020-01-017101653910.1088/2053-1591/ab61acNew insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31BL Toro0https://orcid.org/0000-0002-1994-7507A A Zuleta1https://orcid.org/0000-0002-5431-2603E Correa2https://orcid.org/0000-0003-3837-8992D Calderón3https://orcid.org/0000-0003-3584-3828Y Galindez4https://orcid.org/0000-0001-8584-3303J Calderón5https://orcid.org/0000-0002-5980-4770P Chacón6https://orcid.org/0000-0003-1449-0832A Valencia-Escobar7https://orcid.org/0000-0001-7729-966XF Echeverría E8https://orcid.org/0000-0002-3767-5170Centro de Investigación, Innovación y Desarrollo de Materiales CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia U. de A., Calle 70 No. 52-21, Medellín, ColombiaGrupo de Investigación de Estudios en Diseño—GED, Facultad de Diseño Industrial, Universidad Pontificia Bolivariana, Circular 1a. N° 70-01, Medellín, ColombiaGrupo de Investigación Materiales con Impacto—MAT&MPAC, Facultad de Ingenierías, Universidad de Medellín, Carrera 87 No 30—65, Medellín, ColombiaCentro de Investigación, Innovación y Desarrollo de Materiales CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia U. de A., Calle 70 No. 52-21, Medellín, ColombiaCentro de Investigación, Innovación y Desarrollo de Materiales CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia U. de A., Calle 70 No. 52-21, Medellín, ColombiaCentro de Investigación, Innovación y Desarrollo de Materiales CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia U. de A., Calle 70 No. 52-21, Medellín, ColombiaGrupo de Investigación de Estudios en Diseño—GED, Facultad de Diseño Industrial, Universidad Pontificia Bolivariana, Circular 1a. N° 70-01, Medellín, ColombiaGrupo de Investigación de Estudios en Diseño—GED, Facultad de Diseño Industrial, Universidad Pontificia Bolivariana, Circular 1a. N° 70-01, Medellín, ColombiaCentro de Investigación, Innovación y Desarrollo de Materiales CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia U. de A., Calle 70 No. 52-21, Medellín, ColombiaIn this work, anodic oxide layers on the surface of an AZ31 magnesium alloy were obtained by plasma electrolytic oxidation (PEO) process under low frequency pulsed current. For this, electrolytical solutions containing hexamethylenetetramine and sodium fluoride were used. The morphology and chemical composition of formed coatings were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Also, salt spray test, hydrogen evolution and electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy) were conducted in order to study the corrosion behavior of the coated samples. It was found that the use of low frequency pulsed current for the PEO process reduces the film porosity and increases its thickness, compared with PEO films obtained by continuous anodization. The effect of the pulsed current signal was also analyzed for a two steps PEO process, observing changes in the morphological characteristics of the coatings which allow a better corrosion according electrochemical tests (short term corrosion measurements). However, long term tests results as hydrogen evolution and salt spray tests, indicated the opposite. Both the film porosity and thickness were affected by either the pulsing of the current or the use of a two-step process.https://doi.org/10.1088/2053-1591/ab61acplasma electrolytic oxidationMg–Al–Zn alloyscorrosionanodizingsalt fog test |
| spellingShingle | L Toro A A Zuleta E Correa D Calderón Y Galindez J Calderón P Chacón A Valencia-Escobar F Echeverría E New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B Materials Research Express plasma electrolytic oxidation Mg–Al–Zn alloys corrosion anodizing salt fog test |
| title | New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B |
| title_full | New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B |
| title_fullStr | New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B |
| title_full_unstemmed | New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B |
| title_short | New insights on the influence of low frequency pulsed current on the characteristics of PEO coatings formed on AZ31B |
| title_sort | new insights on the influence of low frequency pulsed current on the characteristics of peo coatings formed on az31b |
| topic | plasma electrolytic oxidation Mg–Al–Zn alloys corrosion anodizing salt fog test |
| url | https://doi.org/10.1088/2053-1591/ab61ac |
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