RT info:eu-repo/semantics/article
T1 Electrochemical characteristics of bioresorbable binary MgCa alloys in Ringer's solution: Revealing the impact of local pH distributions during in-vitro dissolution
A1 Souto, Ricardo Manuel
A1 Mareci, Daniel
A1 Bolat, Georgiana
A1 Izquierdo Pérez, Javier
A1 Crimu, C.
A1 Munteanu, Corneliu
A1 Antoniac, I.
K1 MgCa alloys
K1 corrosion resistance
K1 electrochemical characterization
K1 EIS
K1 SECM
K1 XRD
K1 SEM
K1 local pH distributions
AB Biodegradable magnesium-calcium (MgCa) alloy is a very attractive biomaterial. Two MgCa alloys below the solid solubility of Ca were considered, as to solely investigate the effect of Ca content on the behaviour of magnesium and the pH changes associated to metal dissolution. X-ray diffraction analysis and optical microscopy showed that both Mg-0.63Ca and Mg-0.89Ca alloys were solely composed of α(Mg) phase. Degradation characteristics and electrochemical characterization of MgCa alloys were investigated during exposure to Ringer’s solution at 37 ºC by electrochemical impedance spectroscopy and scanning electrochemical microscopy. The impedance behaviour showed both capacitive and inductive features that are related to the alloy charge transfer reaction and the relaxation of the absorbed corrosion compounds, and can be described in terms of an equivalent circuit. Scanning electron microscopy (SEM) was employed to view the surface morphology of the MgCa samples after 1 week immersion in Ringer’s solution showing extensive precipitation of corrosion products, whereas the substrate shows evidence of a non-uniform corrosion processes. Energy dispersive analysis showed that the precipitates contained oxygen, calcium, magnesium and chlorine, and the Mg:Ca ratios were smaller than in the alloys. Scanning electrochemical microscopy (SECM) was used to visualize local pH changes associated to these physicochemical processes with high spatial resolution. The occurrence of pH variations in excess of 3 units between anodic and cathodic half-cell reactions was monitored in situ
YR 2016
FD 2016
LK http://riull.ull.es/xmlui/handle/915/18998
UL http://riull.ull.es/xmlui/handle/915/18998
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 20-abr-2024