LARISSA OLIVEIRA BERBEL
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Artigo IPEN-doc 29080 Corrosion mechanism of Ti-6Al-4V morse taper dental implants connected to 316 L stainless steel prosthetic abutment2022 - BERBEL, LARISSA O.; VIVEIROS, BARBARA V.G. de; MICELLI, ANA L.P.; NIGRO, FREDERICO; ROSSI, JESUALDO L.; COSTA, ISOLDAThe aim of this work was to investigate the effect of galvanic coupling between stainless steel AISI 316 L abutment type Morse taper and implant made of ASTM F1108–14 Ti-6Al-4V alloy. The assembly of the two alloys was carried out using mechanical imbrication by means of successive strikes at 0.05 J force onto the abutment inserted in the implant along the centerline. Corrosion attack at the interface of the alloys was evaluated according to the number of strikes used for joining the parts. Corrosion resistance was evaluated for the samples by open circuit potential measurements as function of time and scanning vibrating electrode technique (SVET) and scanning ion selective electrode technique (SIET) in phosphate buffer solution with pH adjusted to 3.0, and into which hydrogen peroxide was added to simulate tissue inflammatory conditions. Samples were evaluated at the cross and longitudinal sections. Results indicated that the number of strikes used in assembling affected corrosion susceptibility. The lowest amount of corrosion products was associated to the highest number of strikes used. The corrosion resistance was related to the characteristics of the crevice between the implant and the abutment.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 28131 Study of corrosion of AA 3003 aluminum in biodiesel, diesel, ethanol and gasoline media2020 - SOARES, M.; BERBEL, L.O.; VIEIRA, C.; OLISZESKI, D.C.S.; FURSTENBERGER, C.B.; BANCZEK, E.P.The contact between fuels and various metals used in vehicles make them susceptible to corrosion. Aluminum is a metal widely used in automotive components owing to its corrosion resistance as well as mechanical properties. The ABNT 14359 standard establishes a method for determining fuel corrosion; however, it is restricted to copper and fossil fuels. In this standard, corrosion is assessed qualitatively by visual comparison of patterns, which can lead to uncertain results. The methodology used in this study involves the immersion of metallic materials in fuels for a specific period of time for further analysis by scanning electron microscopy (SEM), and electrochemical analysis by electrochemical impedance spectroscopy (EIS) and anodic potentiodynamic polarization (APP). The results indicated that aluminum alloy AA 3003 is suitable for use in the production of vehicle components that will be in contact with biodiesel, diesel, ethanol, or gasoline, since no serious case of corrosion occurred.Artigo IPEN-doc 26424 Determinants of corrosion resistance of Ti-6Al-4V alloy dental implants in an In Vitro model of peri-implant inflammation2019 - BERBEL, LARISSA O.; BANCZEK, EVERSON do P.; KAROUSSIS, IOANNIS K.; KOTSAKIS, GEORGIOS A.; COSTA, ISOLDABackground Titanium (Ti) and its alloys possess high biocompatibility and corrosion resistance due to Ti ability to form a passive oxide film, i.e. TiO2, immediately after contact with oxygen. This passive layer is considered stable during function in the oral cavity, however, emerging information associate inflammatory peri-implantitis to vast increases in Ti corrosion products around diseased implants as compared to healthy ones. Thus, it is imperative to identify which factors in the peri-implant micro-environment may reduce Ti corrosion resistance. Methods The aim of this work is to simulate peri-implant inflammatory conditions in vitro to determine which factors affect corrosion susceptibility of Ti-6Al-4V dental implants. The effects of hydrogen peroxide (surrogate for reactive oxygen species, ROS, found during inflammation), albumin (a protein typical of physiological fluids), deaeration (to simulate reduced pO2 conditions during inflammation), in an acidic environment (pH 3), which is typical of inflammation condition, were investigated. Corrosion resistance of Ti-6Al-4V clinically-relevant acid etched surfaces was investigated by electrochemical techniques: Open Circuit Potential; Electrochemical Impedance Spectroscopy; and Anodic Polarization. Results Electrochemical tests confirmed that most aggressive conditions to the Ti-6Al-4V alloy were those typical of occluded cells, i.e. oxidizing conditions (H2O2), in the presence of protein and deaeration of the physiological medium. Conclusions Our results provide evidence that titanium’s corrosion resistance can be reduced by intense inflammatory conditions. This observation indicates that the micro-environment to which the implant is exposed during peri-implant inflammation is highly aggressive and may lead to TiO2 passive layer attack. Further investigation of the effect of these aggressive conditions on titanium dissolution is warranted.