RT info:eu-repo/semantics/article
T1 Contributions to a more realistic characterization of corrosion processes on cut edges of coated metals using scanning microelectrochemical techniques, illustrated by the case of ZnAlMg-galvanized steel with different coating densities
A1 Souto, Ricardo Manuel
A1 Bolsanello, Marilia Fernandes
A1 Abreu García, Andrea
A1 Lima, Luciana Xavier da Cruz
A1 Neto, Bruno Kneipel
A1 Ferreira, Jetson Lemos
A1 Rossi, Jesualdo Luiz
A1 Costa, Isolda
A1 Izquierdo Pérez, Javier
A2 Química
A2 Grupo de Electroquímica y Corrosión
Instituto de Materiales y Nanotecnología (IMN)
K1 cut edge
K1 corrosion
K1 SVET
K1 SECM
K1 micropotentiometry
K1 profilometry
K1 SEM-EDS
K1 ZnAlMg
K1 steel
K1 simulated acid rain
AB Corrosion processes at cut edges of galvanized steels proceed as highly localized electrochemical reactions between the exposed bulk steel matrix and the protective thin metallic coating of a more electrochemically active material. Scanning microelectrochemical techniques can thus provide the spatially resolved information needed to assess the corrosion initiation and propagation phenomena, yet most methods scan cut edge sections as embedded in insulating resin to achieve a flat surface for scanning purposes. In this work, the galvanized coatings on both sides of the material were concomitantly exposed to simulated acid rain while characterizing the cut edge response using SECM and SVET techniques, thereby maintaining the coupled effects through the exposure of the whole system as rather realistic operation conditions. The cut edges were shown to strongly promote oxygen consumption and subsequent alkalization to pH 10–11 over the iron, while diffusion phenomena eventually yielded the complete depletion of oxygen and pH neutralization of the nearby electrolyte. In addition, the cathodic activation of the exposed iron was intensified with a thinner coating despite the lower presence of sacrificial anode, and preferential sites of the attack in the corners revealed highly localized acidification below pH 4, which sustained hydrogen evolution at spots of the steel-coating interface.
YR 2024
FD 2024
LK http://riull.ull.es/xmlui/handle/915/38889
UL http://riull.ull.es/xmlui/handle/915/38889
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 27-dic-2024