Artículos de revista DF - FS Aldizkari artikuluak

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Browsing Artículos de revista DF - FS Aldizkari artikuluak by Author "Bonifacich, Federico Guillermo"

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    Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering
    (Rede Latino-Americana de Materiais, 2018) Lambri, Osvaldo Agustín; Giordano, E. D.; Bonifacich, Federico Guillermo; Pérez de Landazábal Berganzo, José Ignacio; Recarte Callado, Vicente; Física; Fisika; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    The changes in the degree of crystallinity in commercial Ethylene Propylene Diene rubber-type M (EPDM) irradiated with neutrons at different doses has been studied by means of inelastic neutron scattering and infrared absorption spectroscopy experiments. EPDM samples were taken from the housing of non-ceramic electrical insulators which are used in outdoor transmission lines of 66 kV. Inelastic neutron scattering spectra were recorded at 5 K with an accessible energy-transfer range between 180 - 3500 cm-1. Infrared studies were performed at room temperature with an energy transfer between 4000 - 400 cm-1. Controlled neutron irradiation allows to obtain different volume fraction and size of crystalline zones in EPDM. The obtained results are discussed and correlated with studies of differential scanning calorimetry, dynamic mechanical analysis and positron annihilation lifetime spectroscopy from where the changes in crystallinity in EPDM were indirectly studied. Inelastic neutron scattering studies were not appropriate for determining the changes in the crystallinity degree in neutron irradiated commercial EPDM. In contrast, from infrared absorption spectroscopy the changes in crystallinity could be determined successfully.
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    PublicationOpen Access
    Evolution of magnetic response as a function of annealing temperature in Fe-based alloys
    (Rede Latino-Americana de Materiais, 2018) Gargicevich, Damián; Bonifacich, Federico Guillermo; Lambri, Osvaldo Agustín; Pérez de Landazábal Berganzo, José Ignacio; Recarte Callado, Vicente; Fisika; Institute for Advanced Materials and Mathematics - INAMAT2; Física; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    The magnetic response, coercive force and magnetic induction, in Fe-10at.% Si, Fe-6at.% Al-9at.% Si and Fe-4at.% Al-8at.% Ge alloys as a function of the annealing temperature was determined and correlated to the microstructural state. The microstructural characterization was made through differential thermal analysis, mechanical spectroscopy and neutron thermodiffraction studies. It has been determined that the increase in the order degree and the decrease in the mobility of structural defects lead to a deterioration of the magnetic quality of the alloys above detailed.
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    PublicationOpen Access
    Influence of defects on the irreversible phase transition in the Fe-Pd doped with Co and Mn
    (Rede Latino-Americana de Materiais, 2018) Bonifacich, Federico Guillermo; Lambri, Osvaldo Agustín; Pérez de Landazábal Berganzo, José Ignacio; Recarte Callado, Vicente; Sánchez-Alarcos Gómez, Vicente; Fisika; Institute for Advanced Materials and Mathematics - INAMAT2; Física; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    The appearance of BCT martensite in Fe-Pd-based ferromagnetic shape memory alloys, which develops at lower temperatures than the thermoelastic martensitic transition, deteriorates the shape memory properties. In a previous work performed in Fe70Pd30, it was shown that a reduction in defects density reduces the non thermoelastic FCT-BCT transformation temperature. In the present work, the influence of quenched-in-defects upon the intensity and temperature of the thermoelastic martensitic (FCC-FCT) and the non thermoelastic (FCT-BCT) transitions in Fe-Pd doped with Co and Mn is studied. Differential scanning calorimetric and mechanical spectroscopy studies demonstrate that a reduction in the dislocation density the stability range of the FCC-FCT reversible transformation in Fe67Pd30Co3 and Fe66.8Pd30.7Mn2.5 ferromagnetic shape memory alloys.
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    PublicationOpen Access
    Polycaprolactone/MSMA composites for magnetic refrigeration applications
    (Wiley, 2024-09-06) Sánchez-Alarcos Gómez, Vicente; Khanna, Deepali; La Roca, Paulo Matías; Recarte Callado, Vicente; Lambri, Fernando Daniel; Bonifacich, Federico Guillermo; Lambri, Osvaldo Agustín; Royo Silvestre, Isaac; Urbina Yeregui, Antonio; Pérez de Landazábal Berganzo, José Ignacio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
    A high filling load (62% weight) printable magnetic composite has been elaborated from the dispersion of magnetocaloric Ni45Mn36.7In13.3Co5 metamagnetic shape memory alloy microparticles into a PCL polymer matrix. The composite material has been prepared by solution method, resulting in a very homogeneous particles dispersion into the matrix. The structural transitions in the polymer are not affected by the addition of the metallic microparticles, which in turn results in a significant increase of the mechanical consistency. The good ductility of the elaborated composite allows its extrusion in flexible printable filaments, from which 3D pieces with complex geometries have been grown. The heat transfer of the composite material has been assessed from finite element simulation. In spite of the achievable magnetocaloric values are moderated with respect to the bulk, numerical simulations confirm that, in terms of heat transference, a PCL/Ni-Mn-In-Co wire is more efficient than a bulk Ni-Mn-In-Co cubic piece containing the same amount of magnetic active material. The quite good magnetocaloric response of the composite and the possibility to print high surface/volume ratio geometries make this material a promising candidate for the development of heat exchangers for clean and efficient magnetic refrigeration applications.
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    PublicationOpen Access
    Study of the martensitic transition in Ni-Mn-Sn-Ti ferromagnetic shape memory alloys
    (Rede Latino-Americana de Materiais, 2018) Bonifacich, Federico Guillermo; Lambri, Osvaldo Agustín; Pérez de Landazábal Berganzo, José Ignacio; Recarte Callado, Vicente; Sánchez-Alarcos Gómez, Vicente; Fisika; Institute for Advanced Materials and Mathematics - INAMAT2; Física; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    In the present work, mechanical spectroscopy measurements as a function of temperature and strain have been performed in (at.%) Ni50Mn37Sn13-xTix (x=0, 0.5 and 2) ferromagnetic shape memory alloys in order both to study martensitic transition phenomenon and also to determine its temperature of appearance. For mechanical spectroscopy measurements, a five elements piezoelectric device recently developed has been used. In addition, other characterization techniques as, differential thermal analysis and superconducting quantum interference magnetic spectroscopy, were also used. Besides, relaxation processes near the martensitic transition temperature have been also observed.