Browsing by Author "Sancy, Mamié"

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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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    Comparison of the protective efficiency of polymethacrylates with different side chain length for AA2024 alloy
    (2021) Sancy, Mamié
    The protective properties of polymethacrylate coatings with different side chain lengths for 2024 aluminum alloys were studied, focusing on the chain length increase but also on the Ar-plasma pretreatment applied to the metal surface. The coatings were obtained by photopolymerization, obtaining reproducible molecular weight polymers during each process that were determined by high-performance liquid chromatography. AA2024 alloy were immersed into the polymethacrylate solution using methyl, butyl, and hexyl as monomers. Their roughness was then evaluated using atomic force microscopy. Surface hydrophobicity and contact angle hysteresis were analyzed in water and diiodomethane. Protective properties were evaluated by electrochemical impedance spectroscopy after 56 days of immersion in a 0.1 M Na2SO4. The alloy cross-sections were examined by field emission scanning electron microscopy and glow discharge optical emission spectroscopy, allowing the estimation of film thickness. Surface analysis revealed that the defect population densities in the coatings increased the monomer alkyl chain length. The immersion thickness increase was consistent with contact angle measurements taken over time, and independent from the chain length. Contradicting expectations, the results showed the protective efficacy was not related to the chain length, since after exposure, the PBMA film revealed the best anti-corrosive coating performance on the AA2024. This was possibly influenced by its polymeric film conformation, hydrophilicity, ordering and lower density of defects on the metal surface. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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    Effect of a bacterial consortium on passivation property of 2024 aluminum alloy
    (2019) Ortega Ulloa, Daniela Elena; Alvarado, C.; Munoz, L.; Kohler, H.; Pineda Parra, Fabiola Makarena; Paez, M.; Sancy, Mamié; Vejar, N.D.; Blamey, J.M.
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    Effect of added porosity on a novel porous Ti-Nb-Ta-Fe-Mn alloy exposed to simulated body fluid
    (2020) Guerra Figueroa, Carolina Andrea; Sancy, Mamié; Walczak, Magdalena; Martínez, Constanza; Ringuede, A.; Cassir, M.; Han, J.; Ogle, K.; Melo, H. G. de; Salinas, V.; Aguilar, C.
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    Effect of hazardous bacteria isolated from copper plumbing system on microbiologically influenced corrosion of copper
    (2019) Galarce, Carlos; Pineda Parra, Fabiola Makarena; Fischer Montt, Diego A.; Flores, M.; Vargas Cucurella, Ignacio Tomás; Sancy, Mamié; Pizarro Puccio, Gonzalo E.
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    Effect of porosity on mechanical and electrochemical properties of Ti-6Al-4V alloy
    (2020) Martínez, Constanza; Guerra Figueroa, Carolina Andrea; Silva, D.; Cubillos, M.; Briones, F.; Muñoz, L.; Paez, M. A.; Aguilar, C.; Sancy, Mamié
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    Electrochemical and tribological evaluation of porous Ti alloys for orthopedic use
    (2020) Guerra Figueroa, Carolina Andrea; Walczak, Magdalena; Sancy, Mamié; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    La demanda de materiales utilizados en aplicaciones de biomedicina ha crecido en los últimos años, lo que ha provocado el interés por estudiar nuevos materiales metálicos. Las aleaciones porosas a base de Ti han demostrado su idoneidad para el reemplazo óseo, como los implantes dentales y las prótesis de cadera, ya que tienen un módulo de elasticidad similar al hueso. Sin embargo, la presencia de poros implica una mayor superficie en contacto con los fluidos corporales, lo que presenta un riesgo potencial en términos de corrosión y/o desgaste, como iones metálicos, partículas metálicas en el torrente sanguíneo. En este contexto, el objetivo de esta tesis doctoral fue explorar las aleaciones a base de Ti con estructura porosa y evaluar su degradación en soluciones corporales simuladas. Por tanto, las muestras se prepararon mediante pulvimetalurgia con variación de porcentajes de porosidad, caracterizadas principalmente por técnicas electroquímicas y mecánicas. Los resultados electroquímicos sugirieron que la aleación porosa a base de Ti no se vio influenciada por el porcentaje de porosidad, ya que la pasividad se mantuvo incluso en espacios reducidos. Por tanto, no se produjo un aumento en la velocidad de corrosión. Por otro lado, la porosidad mejoró la compatibilidad biomecánica a través del módulo elástico. Al mismo tiempo, las propiedades tribológicas mostraron que la presencia de poros evitaría el mecanismo de desgaste de tres cuerpos, mejorando el desgaste y coeficiente de fricción.La demanda de materiales utilizados en aplicaciones de biomedicina ha crecido en los últimos años, lo que ha provocado el interés por estudiar nuevos materiales metálicos. Las aleaciones porosas a base de Ti han demostrado su idoneidad para el reemplazo óseo, como los implantes dentales y las prótesis de cadera, ya que tienen un módulo de elasticidad similar al hueso. Sin embargo, la presencia de poros implica una mayor superficie en contacto con los fluidos corporales, lo que presenta un riesgo potencial en términos de corrosión y/o desgaste, como iones metálicos, partículas metálicas en el torrente sanguíneo. En este contexto, el objetivo de esta tesis doctoral fue explorar las aleaciones a base de Ti con estructura porosa y evaluar su degradación en soluciones corporales simuladas. Por tanto, las muestras se prepararon mediante pulvimetalurgia con variación de porcentajes de porosidad, caracterizadas principalmente por técnicas electroquímicas y mecánicas. Los resultados electroquímicos sugirieron que la aleación porosa a base de Ti no se vio influenciada por el porcentaje de porosidad, ya que la pasividad se mantuvo incluso en espacios reducidos. Por tanto, no se produjo un aumento en la velocidad de corrosión. Por otro lado, la porosidad mejoró la compatibilidad biomecánica a través del módulo elástico. Al mismo tiempo, las propiedades tribológicas mostraron que la presencia de poros evitaría el mecanismo de desgaste de tres cuerpos, mejorando el desgaste y coeficiente de fricción.
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    Electrochemical behavior of stainless steels for sudomotor dysfunction applications
    (2018) Calmet, A.; Vejar, N.; Gonzalez, X.; Sancy, Mamié; Ringuedé, A.; Lair, V.; Griveau, S.; Zagal, J.H.; Bedioui, F.; Cassir, M.
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    Electrochemical dynamic sensing of hydrogen peroxide in the presence of microorganisms
    (2019) Gulppi, Miguel; Muñoz, Lisa; Vejar, Nelson; Blarney, Jenny M.; González, Evelyn; Azócar, Manuel; Sancy, Mamié; Molina, Paulo; Zagal, José H.; Paez, Maritza
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    Evolution of oxide film on the internal porosity of Ti-30Nb-13Ta-2Mn alloy foam
    (2018) Guerra Figueroa, Carolina Andrea; Sancy, Mamié; Walczak, Magdalena; Silva, Daniela; Martínez, Carola; Tribollet, Bernard; Aguilar González, Claudio
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    Improving the interaction between aluminum surfaces and polymer coatings
    (2019) Muñoz, Lisa; Pineda Parra, Fabiola Makarena; Martínez, Carola; Sancy, Mamié; Urzúa, Marcela; Flores, Marcos; Encinas, María V.; Paez, Maritza A.
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    Influence of Porosity on the Elastic Modulus of Ti-Zr-Ta-Nb Foams with a Low Nb Content
    (2019) Aguilar González, Claudio; Arancibia, M.; Alfonso, I.; Sancy, Mamié; Tello, K.; Salinas, V.; De Las Cuevas, F.
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    Influence of the synthesis technique on tribological behavior of a Ti-6Al-4V alloy
    (2020) Martinez, C.; Briones, F.; Araya, N.; Aguilar, C.; Machado, I.; Guerra Figueroa, Carolina Andrea; Medina, A.; Sancy, Mamié
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    Linear versus volcano correlations for the electrocatalytic oxidation of hydrazine on graphite electrodes modified with MN4 macrocyclic complexes
    (2014) Tasca, Federico; Recio Cortés, Francisco Javier; Venegas Toledo, Ricardo Alberto; Geraldo, Daniela A.; Sancy, Mamié; Zagal, José H.
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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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    Powder Metallurgy Production of Ti-2 Wt Pct Si Alloy : Structural, Mechanical, and Electrochemical Characterization of the Sintered Material
    (2020) Guzman, D.; Muranda, D.; Soliz, A.; Aguilar, C.; Guzman, A.; Sancy, Mamié; Pineda Parra, Fabiola Makarena; Rojas, P.
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    Study of an Antarctic thermophilic consortium and its influence on the electrochemical behavior of aluminum alloy 7075-T6
    (2020) Atalah, J.; Blamey, L.; Kohler, H.; Alfaro Valdes, H. M.; Galarce Gutiérrez, Carlos Alejandro; Alvarado, C.; Sancy, Mamié; Páez, M.; Blamey, J. M.
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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 Staphylococcus aureus on the electrochemical behavior of porous Ti-6Al-4V alloy
    (2020) Silva Barbieri, Daniela Carolina; Guerra Figueroa, Carolina Andrea; Munoz, H.; Aguilar, C.; Walter, M.; Azocar, M.; Munoz, L.; Gurbuz, E.; Ringuede, A.; Sancy, Mamié; Cassir, M.