Browsing by Author "Arcos, Camila"

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    Corrosion Analysis of a Ni-Al Bronze for Fuel Cell Applications
    (2025) Sancy, Mamié; Arcos, Camila; Guerra, Carolina; Ringuedé, Armelle; Noel, Corentin
    Global energy demand has increased significantly due to world population growth and the industrialization of developing economies. Its production has been based mainly on fossil-fuel energy, increasing the global warming effect upon the rise of greenhouse gases in the atmosphere, such as carbon dioxide (CO2). In this context, the International Energy Agency reported that the global temperature will increase by 2.7 °C by 2100, which can be decreased by using renewable energies, as written by the United Nations Framework Convention on Climate Change. Moreover, according to the last report of the Intergovernmental Panel on Climate Change, it is crucial to substantially reduce CO2 emissions and other greenhouse gases to improve air quality and stabilize global temperatures. However, nowadays, world energy generation from renewable resources, such as wind, solar, hydroelectric, biomass, tidal, and geothermal, only corresponds to 40%. Fuel cell technology is an excellent opportunity for reducing the dependence on fossil fuels and carbon footprint production. FC uses clean energy with a high conversion efficiency and system configuration that facilitates the easy capture of CO2. Different FC exists according to the operation temperature, the electrolyte chemical nature, and the fuel, increasing the conversion efficiency at higher temperatures, such as in Molten Carbonate Fuel Cells and Solid Oxide Fuel Cells, or even more recent Hybrid Fuel Cells, combining both previously mentioned technologies. Although FC has existed for decades, challenges exist to improve its efficiency. Therefore, developing new functional materials for innovative devices or applications is crucial in our changing world. New paradigms are necessary to produce cleaner energy or cheaper and more efficient materials for transport or other domains. This work focuses on the corrosion performance of a nickel-aluminum bronze alloy (NAB) obtained by laser powder bed fusion exposed to molten carbonate at high temperatures under a hydrogen/nitrogen atmosphere. Using electrochemical measurements and surface analyses, NAB samples were monitored before and after 120 hours of exposure between 550 and 650 °C. Scanning electron microscopy and X-ray photoelectron spectroscopy of NAB demonstrated that an oxide film was formed on the NAB surface, rich in Al2O3 and Cu2O. Open circuit potential and impedance analysis of NAB revealed that the oxide film was stable under the exposure condition. In addition, the impedance analyses showed a capacitive behavior associated with a porous behavior, relate to the oxide film, and a Warburg impedance
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    The Effect of the Addition of Copper Particles in High-Density Recycled Polyethylene Matrices by Extrusion
    (2022) Arcos, Camila; Munoz, Lisa; Cordova, Deborah; Munoz, Hugo; Walter, Mariana; Azocar, Manuel I.; Leiva, Angel; Sancy, Mamie; Rodriguez-Grau, Gonzalo
    In this study, the effect of the recycling process and copper particle incorporation on virgin and recycled pellet HDPE were investigated by thermo-chemical analysis, mechanical characterization, and antibacterial analysis. Copper particles were added to pellet HDPE, virgin and recycled, using a tabletop single screw extruder. Some copper particles, called copper nano-particles (Cu-NPs), had a spherical morphology and an average particle size near 20 nm. The others had a cubic morphology and an average particle size close to 300 nm, labeled copper nano-cubes (Cu-NCs). The thermo-chemical analysis revealed that the degree of crystallization was not influenced by the recycling process: 55.38 % for virgin HDPE and 56.01% for recycled HDPE. The degree of crystallization decreased with the addition of the copper particles. Possibly due to a modification in the structure, packaging organization, and crystalline ordering, the recycled HDPE reached a degree of crystallization close to 44.78% with 0.5 wt.% copper nano-particles and close to 36.57% for the recycled HDPE modified with 0.7 wt.% Cu-NCs. Tensile tests revealed a slight reduction in the tensile strength related to the recycling process, being close to 26 MPa for the virgin HDPE and 15.99 MPa for the recycled HDPE, which was improved by adding copper particles, which were near 25.39 MPa for 0.7 wt.% copper nano-cubes. Antibacterial analysis showed a reduction in the viability of E. coli in virgin HDPE samples, which was close to 8% for HDPE containing copper nano-particles and lower than 2% for HDPE having copper nano-cubes. In contrast, the recycled HDPE revealed viability close to 95% for HDPE with copper nano-particles and nearly 50% for HDPE with copper nano-cubes. The viability of S. aureus for HDPE was lower than containing copper nano-particles and copper nano-cubes, which increased dramatically close to 80% for recycled HDPE with copper nano-particles 80% and 75% with copper nano-cubes.