The effects of Zn segregation and microstructure length scale on the corrosion behavior of a directionally solidified Mg-25 wt.%Zn alloy

Author(s)

Verissimo, Nathalia C. ; Freitas, Emmanuelle S. ; Cheung, Noe ; Garcia, Amauri ; Osorio, Wislei R.

• Document type: Journal article
• Source: Journal of Alloys and Compounds; v. 723, p. 649-660, NOV 5 2017.
• Web of Science Citations: 16

Abstract

Biodegradable implants can be used in order to avoid removal surgery. Mg-Zn alloys are considered interesting alternatives for biomedical applications, however, studies concerning the effects of microstructural features in the as-solidified condition and segregation aspects on the resulting electrochemical behavior are scarce. This investigation is focused on the evaluation of the electrochemical corrosion of an as-solidified Mg-25 wt.% Zn alloy in a 0.15 M NaCl solution at 25 degrees C. EIS plots, potentiodynamic polarization curves and equivalent circuits are used. It is shown that Zn segregation affects both the galvanic couple and the cathode-to-anode area ratio. It was found that finer and homogeneously distributed Mg-rich six-fold branched equiaxed dendritic grains induce lower corrosion current density and higher polarization resistance when compared with equivalent results of coarser ones. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/23396-7 - Effects of solidification MicrostructureParameters of Aluminum-based multicomponent alloys (Al-Mg-Si; Al-Sn-Cu; Al-Zn-Mg) on the resistances to Corrosionand tribocorrosion degradation
• Grantee: Amauri Garcia
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50502-5 - Interrelation of thermal and microstructural solidification parameters and corrosion/tribocorrosion behavior of alloys for tribological, biomedical and solder applications
• Grantee: Amauri Garcia
• Support Opportunities: Regular Research Grants