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3 results on '"Granular nanomaterials"'

1. Mechanical Properties of Nanoporous Metallic Ultrathin Films: A Paradigmatic Case

Author

Giulio Benetti, Francesco Banfi, Emanuele Cavaliere, and Luca Gavioli

Subjects
mechanical properties, nanomechanics, metallic nanoparticles, ultrathin porous films, granular nanomaterials, sensors, Chemistry, QD1-999
Abstract

Nanoporous ultrathin films, constituted by a slab less than 100 nm thick and a certain void volume fraction provided by nanopores, are emerging as a new class of systems with a wide range of possible applications, including electrochemistry, energy storage, gas sensing and supercapacitors. The film porosity and morphology strongly affect nanoporous films mechanical properties, the knowledge of which is fundamental for designing films for specific applications. To unveil the relationships among the morphology, structure and mechanical response, a comprehensive and non-destructive investigation of a model system was sought. In this review, we examined the paradigmatic case of a nanoporous, granular, metallic ultrathin film with comprehensive bottom-up and top-down approaches, both experimentals and theoreticals. The granular film was made of Ag nanoparticles deposited by gas-phase synthesis, thus providing a solvent-free and ultrapure nanoporous system at room temperature. The results, bearing generality beyond the specific model system, are discussed for several applications specific to the morphological and mechanical properties of the investigated films, including bendable electronics, membrane separation and nanofluidic sensing.

Published
2021
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2. Mechanical properties of nanoporous metallic ultrathin film: A paradigmatic case

Author

Benetti, Giulio, Banfi, Francesco, Cavaliere, Emanuele, Gavioli, Luca, Benetti G., Banfi F. (ORCID:0000-0002-7465-8417), Cavaliere E. (ORCID:0000-0002-1934-6760), Gavioli L. (ORCID:0000-0003-2782-7414), Benetti, Giulio, Banfi, Francesco, Cavaliere, Emanuele, Gavioli, Luca, Benetti G., Banfi F. (ORCID:0000-0002-7465-8417), Cavaliere E. (ORCID:0000-0002-1934-6760), and Gavioli L. (ORCID:0000-0003-2782-7414)

Abstract

Nanoporous ultrathin films, constituted by a slab less than 100 nm thick and a certain void volume fraction provided by nanopores, are emerging as a new class of systems with a wide range of possible applications, including electrochemistry, energy storage, gas sensing and supercapacitors. The film porosity and morphology strongly affect nanoporous films mechanical properties, the knowledge of which is fundamental for designing films for specific applications. To unveil the relationships among the morphology, structure and mechanical response, a comprehensive and nondestructive investigation of a model system was sought. In this review, we examined the paradigmatic case of a nanoporous, granular, metallic ultrathin film with comprehensive bottom-up and top-down approaches, both experimentals and theoreticals. The granular film was made of Ag nanoparticles deposited by gas-phase synthesis, thus providing a solvent-free and ultrapure nanoporous system at room temperature. The results, bearing generality beyond the specific model system, are discussed for several applications specific to the morphological and mechanical properties of the investigated films, including bendable electronics, membrane separation and nanofluidic sensing.

Published
2021

3. Caracterización microestructural de las aleaciones base cobre Cu95Co5 Y Cu90Co5Ni5 obtenidas por aleado mecánico y sinterización

Author

López, Marta, Ortiz, Valentina, Gómez, María E., Reyes, David, Mangalaraja, Ramalinga, Prieto, Pedro, and José A. Jiménez

Subjects
caracterización, nanomateriales granulares, characterization, magnetic copper material, materiales magnéticos base cobre, Granular nanomaterials
Abstract

Las aleaciones nanoestructuradas Cu95Co5 y Co90Co5-Ni5 presentan un grado de magnetorresistencia interesante de evaluar para múltiples aplicaciones. Las aleaciones fueron desarrolladas mediante aleado mecánico en un molino planetario bajo atmósfera de argón con tiempos de 30, 45 y 60 horas de molienda a una velocidad de rotación de 155 rpm. Las propiedades magnéticas obtenidas a 300K como función del tiempo de molienda, indican que las aleaciones Cu-Co-Ni muestran un comportamiento cercano al régimen superparamagnético. Con difracción de R-x se corroboró que la disminución de la remanencia Ms, se debe a la reducción de óxidos de cobre y al cambio de fase de Co-fcc a Co-hc. Con la consolidación de las aleaciones molidas, se observa un reforzamiento adicional de la subestructura de grano por la formación de solución sólida CuNi y por precipitación de nanopartículas o monodominios magnéticos de cobalto de tamaño menor a 1nm. Mediante MEB se observó, que las aleaciones Cu-Co-Ni en comparación con aleaciones Cu-Co muestran menor segregación de fases, atribuible a la solubilidad total del Ni en cobre. The magneto-resistant properties of nanostructured Cu95Co5 y Co90Co5-Ni5 alloys show their interesting in candidature for multiple applications. The alloys were obtained by mechanical alloying using a planetary mill with rotational speed of 155rpm under argon atmosphere for 30, 45 and 60h as milling time. The magnetic properties obtained at 300K as a function of milling time reveals that the Cu-Co-Ni alloys show super-paramagnetism behaviour. The XRD analysis indicates that the Ms decreasing is due to the reduction copper oxide and Co structural changes from Co-fcc to Co-hc. An additional strengthening on the grain structure by alloys consolidation have the formation of CuNi solid solutions and precipitations of magnetic domains Co nanoparticles under 1nm in grain size. The SEM observation of CuCoNi alloys with the comparison of CuCo alloys shows the less phase segregation and it is attributed to the complete solubility of Ni in copper.

Published
2010

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