1. Microstructural and Electrochemical Study: Pitting Corrosion Mechanism on A390 Al–Si Alloy and Ce–Mo Treatment as a Better Corrosion Protection †.
- Author
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Herrera Hernández, Héctor, Mandujano Ruiz, Araceli, González Morán, Carlos Omar, Miranda Hernández, José Guadalupe, Flores Cuautle, José de Jesús Agustín, Morales Hernández, Jorge, and Hernández Casco, Irma
- Subjects
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PITTING corrosion , *OXIDE coating , *METALLURGY , *ALLOYS , *CORROSION resistance , *FREQUENCY spectra , *HYPEREUTECTIC alloys - Abstract
Sulfuric acid anodizing assisted by a hydrothermal sealing with inhibitors [Ce3+-Mo6+] was used to prevent pitting corrosion on spray-deposited hypereutectic Al–Si alloy (A390). An investigation concerning the evaluation of pitting corrosion resistance on the anodic oxide thin film with ions incorporated was carried out in NaCl solution using electrochemical measurements (i.e., potentiodynamic polarization and electrochemical impedance spectroscopy, EIS). The influence of Si phase morphology and size on the growth mechanism of an anodic oxide film was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results were then compared with those for its equivalent IM390 alloy (Al-17Si-4.5Cu-0.6Mg) produced through a conventional process ingot metallurgy, IM. The electrochemical findings indicate that sulfuric acid anodizing followed by a simple hot water sealing treatment was ineffective. In this manner, an intense attack was localized by pitting corrosion that occurred on the anodic oxide film in less than three days, as denoted by characteristic changes in the EIS spectra at the lowest frequencies. Improved results were achieved for Ce–Mo surface modification, which can provide better corrosion resistance on the aluminum alloys because no signs of pits were observed during the corrosion testing. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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