LARISSA OLIVEIRA BERBEL
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Artigo IPEN-doc 28936 Niobium- and titanium-based coating for the protection of carbon steel SAE 1020 against corrosion2022 - HELLEIS, RODRIGO; MAIA, GUILHERME A.R.; CASTRO, ERYZA G. de; BERBEL, LARISSA O.; COSTA, ISOLDA; BANCZEK, EVERSON do P.Purpose: The purpose of this paper is to evaluate the protection against corrosion of carbon steel SAE 1020 promoted by a niobium- and titanium-based coating produced from a resin obtained by the Pechini method. Design/methodology/approach: A resin was prepared with ammonium niobium oxalate as niobium precursor and K2TiF6 as titanium precursor. Carbon Steel SAE 1020 plates were dip coated in the resin and calcinated for 1 h at 600 ºC. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to characterize the coating morphologically and structurally. Open circuit potential, electrochemical impedance spectroscopy, anodic potentiodynamic polarization and scanning vibrating electrode technique were used to evaluate the corrosion protection of the coating. Findings: The electrochemical analyses evidence slight protection against corrosion of the coating by itself; however, the needle-like crystal structure obtained may potentially provide a good anchorage site, suggesting the coating could be used as a pretreatment that may present similar application to phosphating processes, generating lower environmental impacts. Originality/value: Due to increasingly restrictive environmental laws, new environmentally friendlier surface treatments must be researched. This paper approaches this matter using a combination of niobium- and titanium-based coating, produced by a cleaner process, the Pechini method.Artigo IPEN-doc 28696 Comparing the corrosion behaviour of AA2050 and AA7050 aluminium alloys by scanning vibrating electrode and scanning ion-selective electrode techniques2022 - VIVEIROS, BARBARA V.G. de; DONATUS, UYIME; ALENCAR, MAICON C. de; BERBEL, LARISSA O.; COSTA, ISOLDAThe susceptibility to localised corrosion of the high strength alloys, AA2050-T84 and AA7050-T7451, used in the aerospace industry, was investigated in this study by localised electrochemical techniques, specifically, scanning vibrating electrode technique (SVET) and scanning ion-selective electrode technique (SIET), in 0.005 mol L−1 NaCl solution. The study was initially carried out using both alloys individually and then, coupling the two alloys and evaluating the effect of galvanic coupling between them. The results revealed that the AA2050-T84, being nobler than the AA7050-T7451, presented higher corrosion current density values when tested in isolation and the depth of corrosion penetration was significantly deeper in the AA2050-T84 alloy than in the AA7050-T7451. However, galvanic coupling of the two alloys resulted in cathodic protection of the AA2050-T84 alloy and a reduction in corrosion current densities on both alloys.Artigo IPEN-doc 24727 Qualitative use of potentiodynamic polarization and anodic hydrogen evolution in the assessment of corrosion susceptibility in AA2198-T851 Al–Cu–Li alloy2018 - DONATUS, UYIME; BERBEL, LARISSA O.; COSTA, ISOLDAIn this study, the corrosion behavior of the AA2198-T851 and its friction stir weldment was used to show the qualitative use of potentiodynamic polarization and the effect of anodic hydrogen evolution (AHE). The results showed that some details can be revealed in the anodic arm of the polarization curves of an Al alloy above the breakdown potential with changes in cell configuration and electrolytes. In addition, AHEinterferes with the measured current density in the anodic arm, which in turn can be used to assess the extent of corrosion susceptibility and changes in anodic dissolution behavior of the alloy.