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Journal of Chemistry
Volume 2016, Article ID 9542942, 11 pages
http://dx.doi.org/10.1155/2016/9542942
Research Article

Corrosion Performance of Cu-Based Coins in Artificial Sweat

1CIICAp, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, 62209 Cuernavaca, MOR, Mexico
2Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, 62210 Cuernavaca, MOR, Mexico
3Universidad Politécnica del Estado de Morelos, Boulevard Cuauhnahuac 566, Col. Lomas del Texcal, 62574 Jiutepec, MOR, Mexico
4Corrosion y Protección (CyP), Buffon 46, 11590 Mexico City, Mexico

Received 8 July 2016; Revised 6 October 2016; Accepted 20 October 2016

Academic Editor: Stefano Caporali

Copyright © 2016 J. Porcayo-Calderon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The performance of different Cu-based coins in artificial sweat was evaluated. The electrochemical behavior of the coins was determined by potentiodynamic polarization curves, linear polarization resistance, and electrochemical impedance spectroscopy. Regardless of the chemical composition of the Cu-based coins, they showed similar polarization curves; particularly, the observed similarity in the anodic zone suggests that the corrosion mechanism is the same in all cases. The presence of Ni and Zn does not appreciably affect the corrosion resistance of Cu. However, the presence of both elements affects the corrosion resistance of Cu. Electrochemical impedance spectroscopy measurements showed the presence of three time constants with very similar characteristics, again indicating that the main corrosion mechanism is the same in all cases. Equivalent circuits confirmed that the corrosion performance of the Ni-Zn-Cu coins depends on the Zn/Ni ratio, such that decreasing this value decreases the corrosion resistance of the alloy. In general, nickel has a detrimental effect due to the formation of highly soluble Ni-based corrosion products.