Browsing by Author "Arcos Segura, Camila Fernanda"

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    Analysis of the microstructure and electrochemical properties of Cu-NiAl used for molten carbonate fuel cell
    (2024) Arcos Segura, Camila Fernanda; Sancy, Mamié; Martínez, Carola; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Global population growth has influenced further technological and scientific challenges, where the exponential increase in electricity demand stands out. In this context, it is necessary to continue researching alternatives to conventional energy generation to reduce greenhouse emissions. Fuel Cell technology is promising for lowering and storing carbon dioxide emissions in this context. It is a backup system to avoid intermittent problems with wind, solar, or other technologies. Fuel cells correspond to an electrochemical device that converts the chemical energy of a fuel directly into electrical energy. Their main components are the electrodes (anode and cathode), electronically conductive, and electrolyte. In particular, molten carbonate fuel cells use hydrogen as fuel, highlighting their excellent power. However, the high working temperature, close to 650 °C, is a disadvantage due to the reduction of the component’s lifetime. Therefore, for a long-term operation, electrode corrosion behavior must be considered. This thesis aims to study Cu-Ni-Al alloys' microstructure and electrochemical behavior for molten carbonate fuel cells. The metal samples were manufactured using powder metallurgical techniques, such as hot pressing and additive manufacturing. The porosity was analyzed using the Archimedes method. The micro-macrostructure of the samples will be studied before and after exposure to Li2CO3-K2CO3 at 550 °C using surface analysis, such as optical microscopy, field emission scanning electron microscopy, and X-ray diffraction. Moreover, gravimetric measurements before and after exposure and electrochemical impedance spectroscopy at open circuit potential were used to analyze the corrosion of the anodes in an aerated and controlled environment.
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    Ni-Al Bronze in Molten Carbonate Manufactured by LPBF: Effect of Porosity Design on Mechanical Properties and Oxidation
    (2023) Arcos Segura, Camila Fernanda; Guerra Figueroa, Carolina Andrea; Jorge A. Ramos-Grez; Sancy, Mamié
    Fuel cell technology has developed due to diminishing dependence on fossil fuels and carbon footprint production. This work focuses on a nickel–aluminum bronze alloy as an anode produced by additive manufacturing as bulk and porous samples, studying the effect of designed porosity and thermal treatment on mechanical and chemical stability in molten carbonate (Li2CO3-K2CO3). Micrographs showed a typical morphology of the martensite phase for all samples in as-built conditions and a spheroid structure on the surface after the heat treatment, possibly revealing the formation of molten salt deposits and corrosion products. FE-SEM analysis of the bulk samples showed some pores with a diameter near 2–5 μm in the as-built condition, which varied between 100 and −1000 μm for the porous samples. After exposure, the cross-section images of porous samples revealed a film composed principally of Cu and Fe, Al, followed by a Ni-rich zone, whose thickness was approximately 1.5 µm, which depended on the porous design but was not influenced significantly by the heat treatment. Additionally, by incorporating porosity, the corrosion rate of NAB samples increased slightly.
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    Suitability of nickel aluminium bronze alloy fabricated by laser powder bed fusion to be used in the marine environment
    (2023) Arcos Segura, Camila Fernanda; Ramos Grez, Jorge; Sancy, Mamié; La Fé Perdomo, Iván; Setchi, R.; Guerra Figueroa, Carolina Andrea
    Nickel aluminium bronze alloy specimens were produced using laser powder bed fusion (LPBF) and subjected to heat treatment to understand their corrosion behaviour when exposed to a 3.5 wt% NaCl solution. Electrochemical analysis, including impedance spectroscopy and polarization curves, was performed to characterize the samples after 30 days of immersion. The findings reveal that the as-built samples exhibit superior corrosion resistance compared to the heat-treated samples, primarily attributed to the lower presence of intermetallic phases, which hinder the alloy's passivation process.
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    The Effect of Adding CeO2 Nanoparticles to Cu–Ni–Al Alloy for High Temperatures Applications
    (2024) Carola Martínez; Arcos Segura, Camila Fernanda; Francisco Briones; Izabel Machado; Mamié Sancy; Marion Bustamante