Papers by Marcos Antonio Coelho Berton
The Balbina Hydroelectric Power Station is located in the central Brazilian Amazon Forest and is ... more The Balbina Hydroelectric Power Station is located in the central Brazilian Amazon Forest and is vulnerable to biofouling and biofilm formation on immersed metal surfaces because of the high ambient temperature near equatorial line. Microbiologically influenced corrosion (MIC) comprises organic and inorganic processes that occur simultaneously or separately and enhance the harmful effects of the dissolution of metal surfaces. Several types of microorganisms are involved in this process, and microbial colonisation of surfaces through biofilm maturation leads to biocorrosion. Each stage of MIC has characteristic microorganisms, and the present study aimed to characterise the different microorganisms found in samples collected from carbon steel, stainless steel, and copper alloy coupons exposed to the water reservoir of the Balbina Hydroelectric Power Station. Microorganisms described in the literature as important for MIC were detected using microbiological tests and molecular tools. In Brazil, 72% of the energy-based power generation is derived from hydropower plants; hence, it is important to study the origin of corrosion on metallic surfaces exposed to the water of the reservoir.
Solar Energy Materials and Solar Cells, Dec 1, 2003
Thin solid films of CeO2-SiO2, used as a counter-electrode layer in electrochromic devices, were ... more Thin solid films of CeO2-SiO2, used as a counter-electrode layer in electrochromic devices, were prepared by the sol–gel dip coating, using an aqueous-based process. The influence of the SiO2 addition on electrochemistry of the CeO2 oxide coatings was determined by chronoamperometric measurements. The films exhibit a larger charge storage capacity, which was determined as a function of the coatings thickness. The peak occurrence in the chronoamperometric curve during the deintercalation of lithium ions in the cerium/silicon films is analyzed in terms of trapping energy levels for Li+ ions into the film.In situ UV–Vis spectroelectrochemical measurements of the CeO2-SiO2 coatings indicated that the films remained transparent in the visible spectral range during the intercalation process. Powders were characterized by X-ray diffraction after the same thermal treatment of the films, indicating a decrease of crystallinity with the doping. The feasibility for use of these electrodes as ion storage for electrochromic devices was investigated.
Proceedings of the 1st International Seminar on Industrial Innovation in Electrochemistry, 2014
In this work, ceria-doped electrolytes with general formula of Ce 0.8 Y 0.2x La x O 1.9 (x=0.00; ... more In this work, ceria-doped electrolytes with general formula of Ce 0.8 Y 0.2x La x O 1.9 (x=0.00; 0.05; 0.10; 0.15; 0.20) were synthesized by combustion method, using glycine as a fuel. The phase identification and morphology of the powders was studied by X-ray diffraction (XRD), surface area measurements (BET) and Raman spectroscopy. The consistency of particle sizes, calculated by the Scherrer formula, and BET measurements suggests that all as-synthesized powders were composed of weakly agglomerated crystallites. After the sintering process (1450 °C/5h) all pellets reach relative densities above 94% of the theoretical density. The contributions of grains and grain boundaries to the total conductivity, were investigated by a.c. impedance spectroscopy, in temperature range of 200-500 °C. The results show that the substitution of the yttrium by lanthanum mainly affects the grain boundary conductivity.
Solar Energy Materials and Solar Cells, 2008
Transparent CeO 2 thin solid films, used as ion storage layer in electrochromic devices were prep... more Transparent CeO 2 thin solid films, used as ion storage layer in electrochromic devices were prepared by the sol-gel method using an alkoxide route combined with the dip-coating technique. The precursor sol was prepared from a mixture of cerium (IV) methoxyethoxide in anhydrous 2-butanol. Electrochemical Li + intercalation/deintercalation was performed by cyclic voltammetry and the results indicate that the CeO 2 /LiClO 4 system is electrochemically reversible. The total inserted/extracted charge of the CeO 2 film was determined by chronoamperometric measurements, which showed an ion storage capacity of $14 mC/cm 2 . The solid-state diffusion of lithium ion into the CeO 2 thin films was investigated by electrochemical impedance spectroscopy. r
Proceedings of the 1st International Seminar on Industrial Innovation in Electrochemistry, 2014
As a contribution to the First International Seminar on Industrial Innovation in Electrochemistry... more As a contribution to the First International Seminar on Industrial Innovation in Electrochemistry -S3iE -held in Curitiba-Pr, Brazil on 16-17 September 2013 a collaborative work between an institute for applied research and supplier of paints for industrial applications, is presented. In this work the kinetics of the cure paint film based on epoxy high solid with VOC-volatile organic compounds was studied by Multi-Speckle Diffusion Wave Spectroscopy technique. The resistivity of paint film was determined by electrochemical impedance spectrosco-ARTICLE TH 9 78 Cure Characteristics of Industrial Commercial Paint Using Diffusion Wave Spectroscopy and the Some Properties of Paint Film Determinated by Electrochemical Impedance Spectroscopy py-EIS. VOC paints have industrial applications that require high resistance to corrosion and wear. The control of the kinetics of paints film is of topmost importance to manufacturers and users in diverse industrial applications in different substrates and conditions. In the kinetics studies of film process formation there is three distinct stages. The first stage was attributed to evaporation of the solvent with a small decrease in the fluidity factor. The second stage present a pronounced decrease of the fluidity factor, consequence of increased viscosity of the paint and reorganization of solid paint particles was observed. The last stage is the cohesion of the paint film, i.e., a complete cure. The Diffusion Wave Spectroscopy technique used to study the kinetic of cure of the paint films showed to be very useful to monitor and display the movement of the laser light scattering within the paint films as a function of time. The chemical characterization of the cured film was done by infrared spectroscopy measurement and for EIS measurements a sample of carbon steel was covered with commercial paint.
Solar Energy Materials and Solar Cells, 2003
Thin solid films of CeO2-SiO2, used as a counter-electrode layer in electrochromic devices, were ... more Thin solid films of CeO2-SiO2, used as a counter-electrode layer in electrochromic devices, were prepared by the sol–gel dip coating, using an aqueous-based process. The influence of the SiO2 addition on electrochemistry of the CeO2 oxide coatings was determined by chronoamperometric measurements. The films exhibit a larger charge storage capacity, which was determined as a function of the coatings thickness. The peak occurrence in the chronoamperometric curve during the deintercalation of lithium ions in the cerium/silicon films is analyzed in terms of trapping energy levels for Li+ ions into the film.In situ UV–Vis spectroelectrochemical measurements of the CeO2-SiO2 coatings indicated that the films remained transparent in the visible spectral range during the intercalation process. Powders were characterized by X-ray diffraction after the same thermal treatment of the films, indicating a decrease of crystallinity with the doping. The feasibility for use of these electrodes as ion storage for electrochromic devices was investigated.
Materials Research, 2001
Thin solid films of CeO2-SnO2 (17 mol% Sn) and CeO2-SnO2:X (X = Li, C and Si) were prepared by th... more Thin solid films of CeO2-SnO2 (17 mol% Sn) and CeO2-SnO2:X (X = Li, C and Si) were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass) at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air.
Electrochimica Acta, 2004
By employing a Tafel equation for the behavior of the metal/film interface and an Ohmic model for... more By employing a Tafel equation for the behavior of the metal/film interface and an Ohmic model for the film itself, it is proposed a qualitatively and quantitatively description for the initial voltammetric transient growths of passivating films on non-noble metals, when they give rise to thin passivating films. General equations are deduced and, as an example of their application, they are used to interpret data obtained during voltammetric growth of ZnO on Zn in a boric/borate buffer solution. The analysis permits the determination of the Flade potential (E F ) of the Zn/ZnO/boric-borate system and the exchange current density and transfer coefficient at the Zn/ZnO interface. In relation to the film itself, it is possible to study, during the transient, the dependence of its ionic specific resistivity on the potential, growth rate, and thickness. All these results are interpreted physically.
ECS Transactions, 2009
Yttrium-doped barium zirconate protonic conductors were synthesized by a two-step route consistin... more Yttrium-doped barium zirconate protonic conductors were synthesized by a two-step route consisting on diffusing barium ions into previously prepared yttrium-doped zirconia. The evolution of the structural phase content was followed by in situ high temperature X-ray diffraction in the ...
Proceedings of the 1st International Seminar on Industrial Innovation in Electrochemistry, 2014
Brazilian Archives of Biology and Technology, 2013
The aim of this study was evaluate, two methods for the detection and identification of sulphate ... more The aim of this study was evaluate, two methods for the detection and identification of sulphate reducing bacteria (SRB): ML medium and PCR with specific primers for SRB groups. SRB were detected through the selective medium only on carbon steel, which showed corrosion. Employing specific PCR primer, SBR were detected from all the metallic components assayed, even those that did not present visible corrosion spots, such stainless steel and copper alloys. Despite the presence or absence of corrosion at the later stages effectively by using the selective medium,, the initial stages of the corrosion could only be detected by the amplification of total DNA with SRB specific primers. The early detection of SRB could be employed for preventing the damages on metal surfaces before the installation of corrosion processes. Strategies for reducing the time spent on SRB isolation and identification could be auxiliary tools for controlling the corrosion of materials.
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Papers by Marcos Antonio Coelho Berton