Browsing by Author "Sancy, Mamié"
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- ItemA Tribological and Ion Released Research of Ti-Materials for Medical Devices(2021) Silva, Daniela ; Montero, M. Cecilia ; Guerra, Carolina ; Martinez Ugalde, Carola ; Li, Xuejie ; Ringuedé, Armelle ; Cassir, Michel ; Ogle, Kevin ; Guzman, Danny ; Aguilar, Claudio ; Paez, Maritza ; Sancy, MamiéThe increase in longevity worldwide has intensified the use of different types of prostheses for the human body, such as those used in dental work as well as in hip and knee replacements. Currently, Ti-6Al-4V is widely used as a joint implant due to its good mechanical properties and durability. However, studies have revealed that this alloy can release metal ions or particles harmful to human health. The mechanisms are not well understood yet and may involve wear and/or corrosion. Therefore, in this work, commercial pure titanium and a Ti-6Al-4V alloy were investigated before and after being exposed to a simulated biological fluid through tribological tests, surface analysis, and ionic dissolution characterization by ICP-AES. Before exposure, X-ray diffraction and optical microscopy revealed equiaxed alpha-Ti in both materials and beta-Ti in Ti-6Al-4V. Scratch tests exhibited a lower coefficient of friction for Ti-6Al-4V alloy than commercially pure titanium. After exposure, X-ray photoelectron spectroscopy and surface-enhanced Raman spectroscopy results showed an oxide film formed by TiO2, both in commercially pure titanium and in Ti-6Al-4V, and by TiO and Al2O3 associated with the presence of the alloys. Furthermore, inductively coupled plasma atomic emission spectroscopy revealed that aluminum was the main ion released for Ti-6Al-4V, giving negligible values for the other metal ions.
- ItemAnalysis of copper slag from a Chilean foundry for application as filler material in thermal energy storage systems(2025) Segovia Araya, Valentina Constanza; Cardemil Iglesias, José Miguel; Sancy, Mamié; Escobar Moragas, RodrigoIn the field of solar thermal storage systems, metallurgical industry by-products have been proposed as filler materials for packed-bed thermal energy storage due to their low cost and suitable thermophysical properties. One of these by-products is copper slag, which has emerged as a competitive option compared to other types of industrial by-products. However, further research of its properties, composition, and heterogeneity is needed to fully address its potential as a storage medium. Approximately 2.2 tons of copper slag is produced per ton of copper extracted, posing disposal challenges for mining companies. Hence, there is growing interest in finding secondary uses for these slags. The present study investigated samples of copper slag from a Chilean foundry disposal site. Elemental and mineral characterization revealed that this heterogeneous material has high iron content with both amorphous and crystalline phases present. The evaluation of thermophysical properties showed stable specific heat capacity that increases with temperature within the range of 100 °C to 450 °C. However, these profiles exhibit variability in heat capacity, particularly at higher temperatures, which decreases with subsequent heating cycles. The results suggest that copper slag has potential as an alternative material for sensible heat storage in packed-bed systems, nonetheless, assessing the variability of its thermophysical properties is crucial to establish its feasibility for sustainable energy solutions.
- ItemAnalysis 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 IngenieríaGlobal 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.
- ItemBiofilm formation on aluminum alloy 2024 : a laboratory study(2015) Sancy, Mamié
- ItemComparison of the protective efficiency of polymethacrylates with different side chain length for AA2024 alloy(2021) Sancy, MamiéThe 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/).
- ItemCorrosion Analysis of a Ni-Al Bronze for Fuel Cell Applications(2025) Sancy, Mamié; Arcos, Camila; Guerra, Carolina; Ringuedé, Armelle; Noel, CorentinGlobal 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
- ItemEffect 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.
- ItemEffect 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.
- ItemEffect 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.
- ItemEffect 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
- ItemElectrochemical 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 IngenieríaLa 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.
- ItemElectrochemical 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.
- ItemElectrochemical 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
- ItemEvolution 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
- ItemImproving 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.
- ItemInfluence 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.
- ItemInfluence 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
- ItemLinear 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.
- ItemNi-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, MamiéFuel 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.
- ItemPowder 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.