abstract
The corrosion resistance of magnesium-based materials is known to be highly sensitive to even trace amounts of noble impurities. In this study, the surface and electrochemical properties of high-purity magnesium (51 ppm Fe) (HPMg) treated in 1 mM chloride solutions of bivalent Cu, Mn, Ni, or Zn cations were investigated by AFM/ SKPFM, H2 evolution measurements, DC-polarization, SEM, and XPS. The goal was to understand the potential effects of galvanic replacement induced by the respective cations. The cathodic kinetics drastically increased on HPMg samples treated in Cu solutions. Additionally, the Volta potential difference (VPD) of HPMg increased following treatment in Cu and Zn solutions. Furthermore, the VPD dropped after subsequent exposure to NaCl, which was attributed to the loss of galvanic coupling between magneisum and the noble deposits formed in a galvanic replacement reaction. In contrast, no significant VPD changes were observed on HPMg surface for Mn and Ni treatments. XPS analysis confirmed that Cu and Zn metals/oxides and Mn and Ni hydroxides were displaced by the corrosion film formed on the HPMg after exposure to NaCl. The observed changes in surface properties and corrosion kinetics of HPMg were rationalized.
keywords
ENHANCED CATALYTIC-ACTIVITY; PROBE FORCE MICROSCOPY; HYDROGEN EVOLUTION; CHARGE COMPENSATION; METAL; IRON; XPS; ALLOY; INHIBITION; BEHAVIOR
subject category
Materials Science; Metallurgy & Metallurgical Engineering
authors
Yasakau, KA; Vaghefinazari, B; Scharnagl, N; Lamaka, S; Zheludkevich, ML
our authors
Kiryl Yasakau
Assistant Researcher
Mikhail Zheludkevich
Invited Principal ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
KY acknowledges the Portuguese Foundation for Science and Tech-nology for the researcher grant (2021.00842.CEECIND) . This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC) .