Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution
The corrosion behavior of Fe-containing directionally solidified (DS) and centrifugally cast (CC) Al-Si-Cu-Zn alloys with either Co or Ni additions has been investigated. Electrochemical and immersion corrosion methods were used to investigate the corrosion behavior in 0.6 M NaCl after short (1-h) a...
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MDPI AG
2022-04-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/12/4/645 |
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| author | Marcella G. C. Xavier Brenda J. M. Freitas Guilherme Y. Koga José E. Spinelli |
| author_facet | Marcella G. C. Xavier Brenda J. M. Freitas Guilherme Y. Koga José E. Spinelli |
| author_sort | Marcella G. C. Xavier |
| collection | DOAJ |
| description | The corrosion behavior of Fe-containing directionally solidified (DS) and centrifugally cast (CC) Al-Si-Cu-Zn alloys with either Co or Ni additions has been investigated. Electrochemical and immersion corrosion methods were used to investigate the corrosion behavior in 0.6 M NaCl after short (1-h) and long (30-day) exposure periods. The employed solidification methods allowed the production of samples with a wide range of secondary dendrite arm spacing (SDAS) while preserving Si and Fe-containing phases. The 0.5 wt.% Ni and Co additions led to the growth of the AlFeSi(Ni) and AlFeSi(Co) phases, but no binary AlNi nor AlCo intermetallic particles have been generated. Potentiodynamic polarization studies at early exposure revealed an increase in the corrosion potential as the Ni was added for either fast or slow solidified samples. The electrochemical impedance spectroscopy at early exposure demonstrated that the Ni-modified alloy, on the other hand, was associated with smaller charge transfer resistances, indicating a reduction in the corrosion resistance after a short elapsed time into the electrolyte. However, the 30-day immersion tests revealed much lower corrosion rate of the Ni-modified alloy than the other alloys, while the corrosion rates of the Co-modified and non-modified alloys were similar. In the Ni-containing alloy, a decreased corrosion rate under a long-term corrosion process was attributed to the formation of a thick and dense alumina layer, effectively protecting the surface under such conditions. This work contributes to better knowledge of the corrosion behavior of Ni- and Co-corrected Al industrial scrap compositions. |
| first_indexed | 2024-03-09T10:31:43Z |
| format | Article |
| id | doaj.art-0ebeada6751d4c94b8f86f083d57df86 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T10:31:43Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-0ebeada6751d4c94b8f86f083d57df862023-12-01T21:14:04ZengMDPI AGMetals2075-47012022-04-0112464510.3390/met12040645Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl SolutionMarcella G. C. Xavier0Brenda J. M. Freitas1Guilherme Y. Koga2José E. Spinelli3Graduate Program in Materials Science and Engineering, Federal University of São Carlos, São Carlos 13565-905, SP, BrazilGraduate Program in Materials Science and Engineering, Federal University of São Carlos, São Carlos 13565-905, SP, BrazilGraduate Program in Materials Science and Engineering, Federal University of São Carlos, São Carlos 13565-905, SP, BrazilGraduate Program in Materials Science and Engineering, Federal University of São Carlos, São Carlos 13565-905, SP, BrazilThe corrosion behavior of Fe-containing directionally solidified (DS) and centrifugally cast (CC) Al-Si-Cu-Zn alloys with either Co or Ni additions has been investigated. Electrochemical and immersion corrosion methods were used to investigate the corrosion behavior in 0.6 M NaCl after short (1-h) and long (30-day) exposure periods. The employed solidification methods allowed the production of samples with a wide range of secondary dendrite arm spacing (SDAS) while preserving Si and Fe-containing phases. The 0.5 wt.% Ni and Co additions led to the growth of the AlFeSi(Ni) and AlFeSi(Co) phases, but no binary AlNi nor AlCo intermetallic particles have been generated. Potentiodynamic polarization studies at early exposure revealed an increase in the corrosion potential as the Ni was added for either fast or slow solidified samples. The electrochemical impedance spectroscopy at early exposure demonstrated that the Ni-modified alloy, on the other hand, was associated with smaller charge transfer resistances, indicating a reduction in the corrosion resistance after a short elapsed time into the electrolyte. However, the 30-day immersion tests revealed much lower corrosion rate of the Ni-modified alloy than the other alloys, while the corrosion rates of the Co-modified and non-modified alloys were similar. In the Ni-containing alloy, a decreased corrosion rate under a long-term corrosion process was attributed to the formation of a thick and dense alumina layer, effectively protecting the surface under such conditions. This work contributes to better knowledge of the corrosion behavior of Ni- and Co-corrected Al industrial scrap compositions.https://www.mdpi.com/2075-4701/12/4/645corrosionsolidificationdendritic growthAl-Si-Fe alloysmodificationintermetallics |
| spellingShingle | Marcella G. C. Xavier Brenda J. M. Freitas Guilherme Y. Koga José E. Spinelli Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution Metals corrosion solidification dendritic growth Al-Si-Fe alloys modification intermetallics |
| title | Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution |
| title_full | Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution |
| title_fullStr | Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution |
| title_full_unstemmed | Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution |
| title_short | Effects of Ni and Co on the Corrosion Resistance of Al-Si-Cu-Zn-Fe Alloys in NaCl Solution |
| title_sort | effects of ni and co on the corrosion resistance of al si cu zn fe alloys in nacl solution |
| topic | corrosion solidification dendritic growth Al-Si-Fe alloys modification intermetallics |
| url | https://www.mdpi.com/2075-4701/12/4/645 |
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