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4 results on '"Frederico Orlandini-Keller"'

1. Optimization of a vibrating MEMS electromagnetic energy harvester using simulations

Author

Ilona Lecerf, Pierre Moritz, José Elías Angulo-Cervera, Fabrice Mathieu, David Bourrier, Liviu Nicu, Thierry Leïchlé, Frederico Orlandini-Keller, Thibaut Devillers, Nora M. Dempsey, Guillaume Viau, Lise-Marie Lacroix, Thomas Blon, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Service Instrumentation Conception Caractérisation (LAAS-I2C), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Service Techniques et Équipements Appliqués à la Microélectronique (LAAS-TEAM), Équipe Microsystèmes électromécaniques (LAAS-MEMS), Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Nanomagnétisme (LPCNO), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), ANR-17-EURE-0009,NanoX,Science et Ingénierie à l'Echelle Nano(2017), and ANR-19-CE09-0021,POMADE,Aimants intégrés submillimétriques pour dispositifs portables(2019)

Subjects
General Physics and Astronomy, General Materials Science, Physical and Theoretical Chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Abstract

International audience; Nowadays, wireless sensor networks (WSN) are becoming essential in our daily life. However, a major constraint concerns the energy power supply. Indeed, batteries need to be recharged or replaced often which implies a limited lifetime for WSN nodes. One alternative consists in harvesting mechanical energy from surrounding vibrations of the environment. Using finite element simulations, we report here a complete guideline to optimize a MEMS electromagnetic energy harvester consisting of an in-plane vibrating silicon frame supporting an array of micromagnets that faces a static 2D micro-coil. The dimensioning of the magnet array and the specific design of the coil are addressed, considering patterned 50 µm thick NdFeB films with out of plane magnetization. The optimization of the electromechanical coupling which allows to efficiently convert the energy results from a trade-off between the high magnetic flux gradients produced by the micromagnets and the maximum number of turns of the facing coil.

Published
2022

2. d-HDDR Processing of Nd-Fe-B Based Alloys to Obtain Highly Anisotropic Nanocrystalline Powders

Author

Hidetoshi Takiishi, Leonardo Ulian Lopes, Paulo A.P. Wendhausen, Juliano Assis Baron Engerroff, Frederico Orlandini Keller, and Arthur Alvarez Mascheroni

Subjects
010302 applied physics, Materials science, Scanning electron microscope, Mechanical Engineering, Analytical chemistry, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Nanocrystalline material, Grain size, Crystallography, Mechanics of Materials, Phase (matter), Powder metallurgy, 0103 physical sciences, General Materials Science, Texture (crystalline), 0210 nano-technology, Anisotropy
Abstract

The HDDR (hydrogenation-disproportionation-desorption-recombination) process is an established powder metallurgy route to obtain Nd–Fe–B nanocrystalline powders for bonded magnets manufacturing. Therefore, both conventional (c-HDDR) and dynamic HDDR (d-HDDR) processes has been investigated to obtain Nd-Fe-B-based powders with different characteristics. Magnetic properties were measured by means of a hysteresisgraph and the powder obtained by d-HDDR showed strong anisotropy, allowing a Br of 1.1 T in the bonded magnet, whereas c-HDDR powder was isotropic with a Br of 0.6 T. Microstructural changes were characterized by X-ray diffraction (DRX) and scanning electron microscopy (SEM). X-ray patters of anisotropic powders made by d-HDDR showed high intensity reflection peaks indexed as (004), (105) and (006) planes in the aligning direction, due the texture inducement in c-axis of the main phase (Nd2Fe14B). However, SEM micrographs of c-HDDR powder showed a more homogeneous microstructure, with grain size of ~300 nm, when compared to d-HDDR powder that ranged from 300 nm to 500 nm. This difference is assumed to be the cause of lower intrinsic coercivity found in the c-HDDR powder.

Published
2017

3. Consolidation of HDDR sintered magnets and coercivity enhancement by low-temperature sintering

Author

Frederico Orlandini Keller, Paulo A.P. Wendhausen, and Leonardo Ulian Lopes

Subjects
010302 applied physics, Materials science, Consolidation (soil), Perpendicular magnetic anisotropy, Sintering, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Grain size, Nuclear magnetic resonance, Sintered magnets, Magnet, 0103 physical sciences, Composite material, 0210 nano-technology
Abstract

It is known that the coercivity in Nd-Fe-B magnets is correlated to the grain size as showed by Ramesh et al. [1], where he concluded that coercivity decreases as grain size increases, varying inversely as the logarithm of the square of the average grain size of the magnet.

Published
2017

4. Magnetic and microstructural evolution of Nd-Fe-B processed via HDDR (hydrogenation-disproportionation-desorption-recombination) and Melt-Spinning sintered by SPS (spark plasma sintering)

Author

Paulo A.P. Wendhausen, N. V. Junior, Juliano Assis Baron Engerroff, Frederico Orlandini Keller, L. H. Justo, and Leonardo Ulian Lopes

Subjects
Grain growth, Materials science, Remanence, Magnet, Metallurgy, Spark plasma sintering, Sintering, Melt spinning, Coercivity, Nanocrystalline material
Abstract

The HDDR (hydrogenation — disproportionation — desorption — recombination) technique and Melt-Spinning have proved to be very effective to obtain Nd 2 Fe 14 B nanocrystalline grains and therefore attaining high values of coercivity. Taking into account the remanence dilution effect found in composite magnets made with nanocrystalline powders, the production of fully-dense magnets with such powders would allow for high remanence and high energy-product magnets. One alternative to consolidate such powders whereas the grain growth could be inhibited is by the spark plasma sintering (SPS) technique. This non-conventional technique has been used for sintering new kinds of ferrous and non ferrous materials, especially to consolidate ultra fine grain, nano-structure and nano-powders. In the SPS process, a pulse delectric current flows through the powder, and then generates local heating at the particle interfaces [1]. Due to its possibility of imposing high heating rates with simultaneous application of pressure, one expects the grain growth to be limited and therefore the high coercivity and remanence could be preserved for the HDDR [2] and Melt-Spinning materials.

Published
2015

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