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Corrosion Behavior of Al Modified with Zn in Chloride Solution
| Content Provider | MDPI |
|---|---|
| Author | Jes, ús Porcayo Calderón Jos, é Luis Reyes Barragán Cinthya, Dinorah Arrieta González Kevin, Piedad Sánchez Roberto, Ademar Rodríguez-Díaz Mejía, Héctor Cruz Vázquez, Víctor Ravelero Fierro, Jesús Israel Barraza Torres-Mancera, María Teresa Retes-Mantilla, Rogel Fernando |
| Copyright Year | 2022 |
| Description | Aluminum-based alloys have been considered candidate materials for cathodic protection anodes. However, the Al-based alloys can form a layer of alumina, which is a drawback in a sacrificial anode. The anodes must exhibit uniform corrosion to achieve better performance. Aluminum can be alloyed with Zn to improve their performance. In this sense, in the present research, the electrochemical corrosion performance of Al-xZn alloys (x = 1.5, 3.5, and 5 at.% Zn) exposed to 3.5 wt.% NaCl for 24 h was evaluated. Polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) were used to identify the electrochemical behavior. The microstructure of the samples before the corrosion assessment was characterized by means of X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). In addition, microstructures of the corroded surfaces were characterized using X-ray mappings via SEM. Polarization curves indicated that Zn additions changed the pseudo-passivation behavior from what pure Al exhibited in a uniform dissolution regime. Furthermore, the addition of Zn shifted the corrosion potential to the active side and increased the corrosion rate. This behavior was consistent with the proportional decrease in polarization resistance $(R_{p}$) and charge transfer resistance $(R_{ct}$) in the EIS. The analysis of EIS was done using a mathematical model related to an adsorption electrochemical mechanism. The adsorption of chloride at the Al-Zn alloy surface formed aluminum chloride intermediates, which controlled the rate of the process. The rate constants of the reactions of a proposed chemical mechanism were evaluated. |
| Starting Page | 4229 |
| e-ISSN | 19961944 |
| DOI | 10.3390/ma15124229 |
| Journal | Materials |
| Issue Number | 12 |
| Volume Number | 15 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2022-06-15 |
| Access Restriction | Open |
| Subject Keyword | Materials Analytical Chemistry Al Alloy Al-zn Alloy Corrosion Electrochemical Techniques |
| Content Type | Text |
| Resource Type | Article |
