GI. Electroquímica y Corrosión
http://riull.ull.es/xmlui/handle/915/19234
2024-03-29T00:30:06ZSebacate intercalated Ca-Al layered double hydroxide pigments for corrosion protection of low carbon steel: anion exchange and electrochemical properties
http://riull.ull.es/xmlui/handle/915/36285
Sebacate intercalated Ca-Al layered double hydroxide pigments for corrosion protection of low carbon steel: anion exchange and electrochemical properties
Souto Suárez, Ricardo Manuel; Cristoforetti, Andrea; Parola, Federico; Parrino, Francesco; Izquierdo, Javier; Rossi, Stefano; Deflorian, Flavio; Fedel, Michele
Sebacate (SB) molecules were incorporated into Ca–Al layered double hydroxides (CaAL-LDH) using a hydrothermal method. The resulting products underwent characterization through X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. To investigate the release kinetics and thermodynamics of the
corrosion inhibitor, total organic carbon analysis (TOC) was employed. A comparison was made with CaAl-LDH
prepared without corrosion inhibitors, in which nitrates were the primary anions within the layered clay
structure. An assessment of anion exchange between nitrates and chlorides was conducted using total nitrogen
analysis (TN). The SB anion comprised approximately 49.2% of the total dried powder synthesized, with a
maximum release efficiency of around 86.7% fitting a Langmuir model. For the evaluation of the corrosion inhibition effect on steel surfaces, electrochemical impedance spectroscopy, potentiodynamic polarization, and
scanning vibrating electrode technique were employed. The corrosion inhibition impact was ascribed to the
liberation of SB anions from the CaAl-LDH pigments, accompanied by alkalinization stemming from partial
particle dissolution. Additionally, the incorporation of organic molecules notably enhanced the stability of
pigments in aqueous solutions compared to similar ones hosting nitrates. These findings suggested that CaAl-LDH
pigments have potential as nanocontainers for organic inhibitors, showing promising prospects in the field of
corrosion research.
2024-01-01T00:00:00ZApplicability of voltammetric modes in scanning electrochemical microscopy for in situ corrosion characterisation of copper-based materials
http://riull.ull.es/xmlui/handle/915/34619
Applicability of voltammetric modes in scanning electrochemical microscopy for in situ corrosion characterisation of copper-based materials
Souto, Ricardo Manuel; Hernández-Concepción, Brenda; Méndez-Guerra, A.; Izquierdo Pérez, Javier
Chemical imaging of corrosion processes involving copper species using scanning electrochemical microscopy has been hampered by the lack of soluble oxidation states for copper that
can be achieved by amperometric conversion at the tip. Indeed, the only possibility is to reduce the
corrosion products at the tip, thus modifying the chemical response of the electrode material and
requiring subsequent redissolution of the copper deposits. Consequently, the limitations arising from
the system prevented a full-scale quantification, requiring the development of new methodologies
or the optimisation of those currently available, as we pursued with the present work. Therefore,
the voltammetric behaviours of gold macro- and microelectrodes were evaluated with respect to the
collection and redissolution of Cu2+ ions, with the aim of using them as sensing probes in scanning
electrochemical microscopy (SECM) to investigate the activity of copper surfaces in acidic chloridecontaining environments. Cyclic and square-wave voltammetric techniques were explored for copper
collection and subsequent stripping on Au microelectrode tips in SECM with the objective to capture
in situ image electrochemical reactivity distributions across copper surfaces undergoing corrosion.
Metals 13 (2023) 1965, 17 pp.
https://doi.org/10.3390/met13121965
2023-01-01T00:00:00ZIn-situ measurement of electrochemical activity related to filiform corrosion in organic coated steel by scanning vibrating electrode technique and scanning micropotentiometry
http://riull.ull.es/xmlui/handle/915/34616
In-situ measurement of electrochemical activity related to filiform corrosion in organic coated steel by scanning vibrating electrode technique and scanning micropotentiometry
Souto, Ricardo Manuel; Cristoforetti, A.; Izquierdo, Javier; Deflorian, F.; Fedel, M.; Rossi, S.
A new approach to studying the mechanism of filiform corrosion in organic coated steel based on the scanning
vibrating electrode technique (SVET) and micropotentiometry (potentiometric SECM) is presented. The elec trochemical activity of the process under the coating is evaluated by mapping the ionic current densities
emanating from some artificial defects made in specific locations of the filament identifiable thanks to the
transparency of the coating. In addition, antimony tips are employed to investigate the pH changes associated to
the different corrosion reactions at the metal-paint interface. Local pH levels associated to anodic and cathodic
regions are determined along the filament.
2024-01-01T00:00:00ZNovel dynamic method based on CV-SECM and SWV-SECM for the in situ chemical imaging of reactive metal surfaces undergoing corrosion and corrosion inhibition illustrated with the case of copper corrosion inhibition by benzotriazole.
http://riull.ull.es/xmlui/handle/915/34615
Novel dynamic method based on CV-SECM and SWV-SECM for the in situ chemical imaging of reactive metal surfaces undergoing corrosion and corrosion inhibition illustrated with the case of copper corrosion inhibition by benzotriazole.
Souto, Ricardo Manuel; Hernández-Concepción, Brenda; Izquierdo, Javier
A novel dynamic method for the chemical imaging of actively corroding metal surfaces using scanning electrochemical microscopy (SECM) is proposed by using CV-SECM and SWV-SECM. This consists of an adequate coupling of a repetitive voltammetric operation at the SECM tip while conducting the rastering routine for scanning a reactive copper surface, as well as its inhibition by benzotriazole. In this method, gold microelectrodes are employed as SECM tips, and therefore their electrochemical behaviour towards collection and redissolution of Cu2+ ions from synthetic solutions containing Cu2+ ions. Next, the dynamic application of voltammetric methods for the collection and stripping of copper on the Au probes while mapping copper surfaces was investigated. The proof of concept first involved continuous cyclic voltammetry (CV-SECM) in an acidified NaCl solution, in terms of Cu2+dissolution and surface redox activity (with SECM in the feedback mode). Then, square wave voltammetry (SWV-SECM) was used to detect small copper dissolution from corroding and inhibitor-protected metal surfaces. The results are consistent with a heterogeneous nature of copper degradation and the development of protective films and passive layers.
2024-01-01T00:00:00Z