82 results on '"Luciano Pilloni"'
Search Results
2. Early failure of a locked titanium plate in a proximal humeral fracture: Case report and metallurgic analysis
- Author
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Giandomenico Logroscino, Fabrizio Donati, Michela Saracco, Luciano Pilloni, and Corrado Piconi
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Surgery ,RD1-811 - Abstract
Angular stability locking plates are commonly used in proximal humeral fractures, especially in old patients with osteoporotic bones. These implants show good results in short and midterm follow-up, but complications are not uncommon. Here we present a case report to describe a case of early failure of a proximal angular stability plate implanted in a 72 years old female with a highly unstable two part proximal humeral fracture. An optical and metallurgic analysis was also conducted to study the modalities of failure. We concluded that anatomic reduction and restoration of the medial cortical support are crucial in order to minimize the mechanical load on the bone–metal interface and to prevent mechanical failure, in particular when the fracture rim drop in the weak point of the plate that was found in the proximal two symmetric holes (Holes E). Keywords: Proximal humerus fracture, Plate failure, Angular stability locking plate, Metallurgic plate analysis
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- 2018
- Full Text
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3. On Tailoring Co-Precipitation Synthesis to Maximize Production Yield of Nanocrystalline Wurtzite ZnS
- Author
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Radenka Krsmanović Whiffen, Amelia Montone, Loris Pietrelli, and Luciano Pilloni
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zinc sulfide ,wurtzite ,co-precipitation synthesis ,solvent recycling ,green synthesis ,scaling up ,Chemistry ,QD1-999 - Abstract
Pyroelectric materials can harvest energy from naturally occurring ambient temperature changes, as well as from artificial temperature changes, notably from industrial activity. Wurtzite- based materials have the advantage of being cheap, non-toxic, and offering excellent opto-electrical properties. Due to their non-centrosymmetric nature, all wurtzite crystals have both piezoelectric and pyroelectric properties. Nanocrystalline wurtzite ZnS, being a room temperature stable material, by contrast to its bulk counterpart, is interesting due to its still not well-explored potential in piezoelectric and pyroelectric energy harvesting. An easy synthesis method—a co-precipitation technique—was selected and successfully tailored for nanocrystalline wurtzite ZnS production. ZnS nanopowder with nanoparticles of 3 to 5 nm in size was synthesized in ethyl glycol under medium temperature conditions using ZnCl2 and thiourea as the sources of Zn and S, respectively. The purified and dried ZnS nanopowder was characterized by conventional methods (XRD, SEM, TEM, TG and FTIR). Finally, a constructed in-house pilot plant that is able to produce substantial amounts of wurtzite ZnS nanopowder in an environmentally friendly and cost-effective way is introduced and described.
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- 2021
- Full Text
- View/download PDF
4. A Simple Ball Milling and Thermal Oxidation Method for Synthesis of ZnO Nanowires Decorated with Cubic ZnO2 Nanoparticles
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Antonio Rinaldi, Marialilia Pea, Andrea Notargiacomo, Eloisa Ferrone, Sebastiano Garroni, Luciano Pilloni, and Rodolfo Araneo
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ZnO nanowires ,Zn powders ,ball milling ,thermal oxidation ,core-shell nanowires ,Chemistry ,QD1-999 - Abstract
In this work, we propose the synthesis of ZnO nanostructures through the thermal oxidation of ball-milled powders with the introduction of Mg and Sn doping species at the preliminary step of milling. We investigate the advantages and challenges of this two steps process for the production and fabrication of highly crystalline ZnO nanowires. This simple method allows us to fabricate ZnO nanowires with a higher quality core crystal at a much lower temperature and for a shorter processing time than the state-of-the-art, and decorated with by ZnO2 nanoparticles as determined via TEM analysis. The main findings will show that the crystalline core of the nanowires is of hexagonal ZnO while the nanoparticles on the surface are ZnO2 cubic type. Generally, the method proves to be suitable for applications that require a high surface-to-volume ratio, for example, catalysis phenomena, in which the presence of zinc oxides species can play an important role.
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- 2021
- Full Text
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5. Cu Nano-Roses Self-Assembly from Allium cepa, L., Pyrolysis by Green Synthesis of C Nanostructures
- Author
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Paola De Padova, Amanda Generosi, Barbara Paci, Bruno Olivieri, Carlo Ottaviani, Claudio Quaresima, Lorenza Suber, Fabio Di Pietrantonio, Giancarlo Della Ventura, Luciano Pilloni, S Supriya, and Gurumurthy Hegde
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Allium cepa, L., pyrolysis ,green carbon nanostructures ,Cu metallic nano-roses ,SEM/EDS ,ED-XRD ,Raman spectroscopy ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Carbon nanostructures are achieved by bio-waste Allium cepa, L., (onion vulgaris) peels through pyrolysis at 900 °C. They contain dispersed elements derived by their bio-precursors, like Mg, Ca, S, Na, K, and Cu. Here, we report the self-assembly of new Cu flower-shaped nanostructures organized as nano-roses. Remarkably, the nano-roses show rolled-up petals of Cu0 with a high chemical stability in air, exhibiting an intrinsic pure Cu crystalline phase. This suggests the exceptional potentiality to synthesize Cu0 nanostructures with novel physical/chemical properties. The size, morphology, and chemical composition were obtained by a combination of high-resolution scanning electron microscopy, energy dispersive X-ray spectroscopy, energy dispersive X-ray diffraction, and Raman spectroscopy.
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- 2020
- Full Text
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6. Silver thiolate nanoclusters as support for chiral ligands: application in heterogeneous phase asymmetric catalysis
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Ludovica Primitivo, Martina De Angelis, Andrea Necci, Federica Di Pietro, Alessandra Ricelli, Daniela Caschera, Luciano Pilloni, Lorenza Suber, and Giuliana Righi
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General Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Atomic and Molecular Physics, and Optics - Abstract
A nanocatalyst with chiral amino alcohol catalytic function was efficiently employed in the Henry reaction, easily recovered by centrifugation and reused without loss of activity.
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- 2023
7. Dense nanocrystalline W alloys: Enhancement of hardness and thermal stability by Al addition
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Francesco Torre, Teodor Huminiuc, Paolo Barra, Luciano Pilloni, Tomas Polcar, Antonio Rinaldi, Francesco Delogu, Roberto Orrù, Giacomo Cao, and Antonio Mario Locci
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General Medicine - Published
- 2023
8. 15/15 Ti Stainless Steel Welding Process Optimization for GEN IV Nuclear Application in the GEMMA Project Frame
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Luciano Pilloni, Claudio Testani, G. Barbieri, Daniele Mirabile Gattia, and F. Cognini
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Materials science ,Mechanics of Materials ,Mechanical Engineering ,Frame (networking) ,Metallurgy ,General Materials Science ,Process optimization ,Condensed Matter Physics ,Gemma ,Stainless steel welding - Abstract
This paper deals with activities carried out in the frame of GEMMA project on welded samples of 15/15 Ti stainless steel. The focus of GEMMA project has been on the investigation of material properties and associated welded joints for GEN IV nuclear plants. The RCC-MRx code uses the standard Base Metal Grade nomenclature (EN/ISO), but provides also additional specifications. Titanium stabilized “15-15Ti” stainless steel has been the primary choice for fuel cladding of current fast spectrum research reactor projects. The choice of cladding material is based on past experiences and the availability of material databases from similar steel grades proven in past sodium-cooled fast reactors programs [1-4]. On the basis of ENEA past experience, a strict specification has been written to realize a new heat treatment of this special stainless steel (SS). One of the main problems faced with this material is the high tendency to crack after the welding process. Several preliminary welding tests permitted to select TIG and laser welding processes for the 15/15 Ti SS. This fact because the main applications involve small thicknesses without filler material. The welding of the 15/15 Ti was performed using a fully automated TIG work station at ENEA CR-Casaccia. The base materials to evaluate the welding parameters were 15/15 Ti plates 100 X 170 X 3 mm welded under different shielding gas atmospheres and process parameters arrangements that permitted to obtain good quality joints avoiding catastrophic hot-cracking. The welded samples underwent a mechanical and metallographic characterization and the main results are here presented.
- Published
- 2021
9. Design of a fluorescent and clickable Ag38(SRN3)24 nanocluster platform: synthesis, modeling and self-assembling
- Author
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Martina De Angelis, Gaetano Campi, Luciano Pilloni, Mauro Satta, Lorenza Suber, Alessandro Fortunelli, Amedeo Palma, Luca Sementa, Giuliana Righi, Ludovica Primitivo, Alessandra Del Giudice, and Daniela Caschera
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Materials science ,XRD ,nanoclusters ,UV-vis ,Bioengineering ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Nanoclusters ,silver ,General Materials Science ,Clickable ,Small-angle X-ray scattering ,theoretical modeling ,General Engineering ,SAXS ,General Chemistry ,fluorescence spectroscopy ,021001 nanoscience & nanotechnology ,Fluorescence ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Surface modification ,0210 nano-technology ,Biosensor ,Stoichiometry ,ATR-FTIR - Abstract
Fluorescent atomically precise Ag38(11-azido-2-ol-undecane-thiolate)24 nanoclusters are easily prepared using sodium ascorbate as a "green"reducer and are extensively characterized by way of elemental analyses, ATR-FTIR, XRD, SAXS, UV-vis, fluorescence spectroscopies, and theoretical modeling. The fluorescence and the atomically determined stoichiometry and structure, the facile and environmentally green synthesis, together with the novel presence of terminal azido groups in the ligands which opens the way to "click"-binding a wide set of molecular species, make Ag38(11-azido-2-ol-undecane-thiolate)24 nanoclusters uniquely appealing systems for biosensing, recognition and functionalization in biomedicine applications and in catalysis. This journal is
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- 2021
10. Functionalized Magnetic Nanoparticles as Catalysts for Enantioselective Henry Reaction
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Ludovica Primitivo, Marzia Oneto Domenici, Lorenza Suber, Ilaria Ben Romdan, Martina De Angelis, Alessandra Ricelli, Giuliana Righi, Andrea Mastrodonato, Carla Sappino, Luciano Pilloni, Chiara Tatangelo, Sappino, C., Primitivo, L., De Angelis, M., Domenici, M. O., Mastrodonato, A., Romdan, I. B., Tatangelo, C., Suber, L., Pilloni, L., Ricelli, A., and Righi, G.
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Nitroaldol reaction ,General Chemical Engineering ,Enantioselective synthesis ,Nanoparticle ,Alcohol ,General Chemistry ,Diethylzinc ,Combinatorial chemistry ,Article ,Catalysis ,Chemistry ,chemistry.chemical_compound ,chemistry ,Magnetic nanoparticles ,asymmetric catalysis ,magnetic nanoparticles ,Henry reaction ,QD1-999 ,Superparamagnetism - Abstract
With the aim to easily recover and reuse the catalyst, an efficient amino alcohol catalyst previously tested in the asymmetric addition of diethylzinc to several aromatic aldehydes has been immobilized on proper functionalized superparamagnetic core-shell magnetite-silica nanoparticles and employed in the Henry reaction in the semi-homogeneous phase. The nanocatalyst exhibits a promising catalytic activity that remains unchanged in the three catalytic cycles performed. The results prove that highly efficient catalysts, by being immobilized on suitable magnetic nanosupports, can be easily recovered and reused, maintaining their catalytic behavior.
- Published
- 2019
11. Achievement of Ultrafine Grain structure by means of recrystallization treatments
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Carlo Cristalli, Oriana Tassa, Luciano Bozzetto, and Luciano Pilloni
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Nuclear and High Energy Physics ,Nuclear Energy and Engineering ,General Materials Science - Published
- 2022
12. Development of innovative materials and thermal treatments for DEMO water cooled blanket
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L. Bozzetto, C. Cristalli, Luciano Pilloni, N. Bettocchi, O. Tassa, E. Zanin, Pilloni, L., Cristalli, C., Tassa, O., Bozzetto, L., Zanin, E., and Bettocchi, N.
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Nuclear and High Energy Physics ,Toughness ,Materials science ,Materials Science (miscellaneous) ,Charpy impact test ,Blanket ,01 natural sciences ,Heat treatment ,010305 fluids & plasmas ,0103 physical sciences ,Ultimate tensile strength ,Tensile ,Irradiation ,Charpy ,Embrittlement ,Microstructure ,010302 applied physics ,EUROFER 97 ,KLST ,RAFM steels ,Metallurgy ,lcsh:TK9001-9401 ,Grain size ,Nuclear Energy and Engineering ,RAFM steel ,lcsh:Nuclear engineering. Atomic power - Abstract
One of the options currently taken into account for the realization of the first DEMO reactor is the “water-cooled lanket”. This option implies an irradiation temperature for the blanket material in the range of 280–350 °C. Therefore, in light of the under irradiation behaviour of EUROFER, namely of the DBTT shift toward high temperature due to the low irradiation temperature embrittlement, the target of the hereby reported activities is the development of much tougher alloys, to try to tolerate the embrittlement due to the low irradiation temperature. We report in this paper the work done to optimize the toughness of Eurofer 97, increasing the normalizing temperature and maintaining a small grain size using multiple normalizing treatments. We report also the mechanical behaviour of two 9Cr1WTa type alloys, produced and tested with the same aim to find alloys more resistant to embrittlement at low irradiation temperature. Keywords: EUROFER 97, RAFM steels, Microstructure, Heat treatment, Tensile, Charpy, KLST
- Published
- 2019
13. Austenitization and Tempering Temperatures Effects on EUROFER 97 Steel
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Luciano Pilloni, Laura Alleva, Claudio Testani, and Andrea Di Schino
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Materials science ,Mechanical Engineering ,Metallurgy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,7. Clean energy ,010305 fluids & plasmas ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,Tempering ,0210 nano-technology - Abstract
EUROFER 97 is considered as standard steel for the nuclear applications in the case of high radiation density for first wall of a fast breeder reactors. Based on such consideration the microstructural behaviour of EUROFER 97 after thermo-mechanical processing is fundamental, since such materials properties are interesting also for innovative solar plants. In this paper the effect of thermo-mechanical behavior on the mechanical properties of EUROFER 97 has been analyzed by hot rolling followed by heat treatment on laboratory scale.A strong effect of reheating conditions before rolling on the material strength, due to an increase of hardenability following the austenite grain growth is found. A limited effect of the hot reduction and of the following tempering behavior is found in the considered deformation-range investigated. A loss of impact toughness is detected together with the hardness improvement.Mechanical properties are depending on the tempering temperature and an improvement of tensile yield stress (YS) and ultimate stress (UTS) was determined in tensile test carried on at T=550°C and T=650°C, e.g.: YS increase from about 400 MPa for standard EUROFER 97 [1] to about 550 MPa in samples treated by a tempering temperature of 720°C instead of the standard 760°C for EUROFER 97. Same trend has been found for UTS results.
- Published
- 2018
14. Grain size reduction strategies on Eurofer
- Author
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I. Salvatori, Luciano Pilloni, C. Cristalli, S. Storai, O. Tassa, Storai, S., Cristalli, C., and Pilloni, L.
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Nuclear and High Energy Physics ,Toughness ,Materials science ,Multiple normalization ,Materials Science (miscellaneous) ,01 natural sciences ,010305 fluids & plasmas ,Brittleness ,Microstructure ,Recrystallization ,EUROFER 97 ,RAFM steels ,KLST ,Asymmetric rolling ,0103 physical sciences ,Tempering ,Embrittlement ,Strengthening mechanisms of materials ,010302 applied physics ,Metallurgy ,lcsh:TK9001-9401 ,Grain size ,Nuclear Energy and Engineering ,RAFM steel ,Martensite ,lcsh:Nuclear engineering. Atomic power ,Grain boundary - Abstract
One of the options currently taken into account for the realization of the first DEMO reactor is the “water-cooled blanket”. This option implies a minimum irradiation temperature for the blanket material in the range of 280–350 °C. In addition to the DBTT (Ductile to Brittle Transition Temperature) shift due to the DPA (displacement per atom) damage under irradiation, also the issue of the increased embrittlement due to He production must be taken into account. This issue appears even more detrimental and less manageable because the DBBT shift due to the Helium production does not saturate with the dose, as it results from previous works reported in literature. The experimental results and the difference in behaviour between ODS (Oxide Dispersion Strengthened Steels) RAFM (Reduced Activation Ferritic Martensitic) and other FM (Ferritic Martensitic) alloys (EM10, P91) showed that it is possible to improve the resistance to He embrittlement by both intra-granular precipitation of Y-Ti oxides and by decreasing the grain size at the same time. Nevertheless, anyway, the multiplication of the grain boundaries increases the dilution of He on grain surface, delaying the formation of He bubbles on grain boundaries and, therefore, the susceptibility to the He embrittlement. Several grain size reduction strategies have then been investigated on EUROFER both at the austenitization stage, on the PAGS (Prior Austenite Grain Size), and at the tempering stage, on the tempered martensite. The microstructural observations have been carried out by means of SEM (Scanning Electron Microscopy). Also the effect of grain size reduction on the toughness of the material will be taken into account; The DBTTs resulting from impact tests on KLST specimens will be shown. The outcomes of the microstructural observations, as well as the preliminary mechanical characterization (impact tests) will be discussed in this paper. Keywords: EUROFER 97, RAFM steels, Microstructure, Multiple normalization, Asymmetric rolling, Recrystallization, KLST
- Published
- 2018
15. On Tailoring Co-Precipitation Synthesis to Maximize Production Yield of Nanocrystalline Wurtzite ZnS
- Author
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Amelia Montone, Luciano Pilloni, Loris Pietrelli, and Radenka Krsmanovic Whiffen
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Materials science ,Coprecipitation ,General Chemical Engineering ,Nanoparticle ,02 engineering and technology ,01 natural sciences ,7. Clean energy ,Article ,scaling up ,lcsh:Chemistry ,chemistry.chemical_compound ,0103 physical sciences ,General Materials Science ,Fourier transform infrared spectroscopy ,solvent recycling ,Wurtzite crystal structure ,010302 applied physics ,co-precipitation synthesis ,green synthesis ,021001 nanoscience & nanotechnology ,Zinc sulfide ,Piezoelectricity ,Nanocrystalline material ,Pyroelectricity ,zinc sulfide ,chemistry ,Chemical engineering ,wurtzite ,lcsh:QD1-999 ,pilot plant ,0210 nano-technology - Abstract
Pyroelectric materials can harvest energy from naturally occurring ambient temperature changes, as well as from artificial temperature changes, notably from industrial activity. Wurtzite- based materials have the advantage of being cheap, non-toxic, and offering excellent opto-electrical properties. Due to their non-centrosymmetric nature, all wurtzite crystals have both piezoelectric and pyroelectric properties. Nanocrystalline wurtzite ZnS, being a room temperature stable material, by contrast to its bulk counterpart, is interesting due to its still not well-explored potential in piezoelectric and pyroelectric energy harvesting. An easy synthesis method—a co-precipitation technique—was selected and successfully tailored for nanocrystalline wurtzite ZnS production. ZnS nanopowder with nanoparticles of 3 to 5 nm in size was synthesized in ethyl glycol under medium temperature conditions using ZnCl2and thiourea as the sources of Zn and S, respectively. The purified and dried ZnS nanopowder was characterized by conventional methods (XRD, SEM, TEM, TG and FTIR). Finally, a constructed in-house pilot plant that is able to produce substantial amounts of wurtzite ZnS nanopowder in an environmentally friendly and cost-effective way is introduced and described.
- Published
- 2021
16. Design of a fluorescent and clickable Ag
- Author
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Gaetano, Campi, Lorenza, Suber, Giuliana, Righi, Ludovica, Primitivo, Martina, De Angelis, Daniela, Caschera, Luciano, Pilloni, Alessandra, Del Giudice, Amedeo, Palma, Mauro, Satta, Alessandro, Fortunelli, and Luca, Sementa
- Abstract
Fluorescent atomically precise Ag
- Published
- 2021
17. Supported catalysts for induction-heated steam reforming of methane
- Author
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Francesca Varsano, Mariangela Bellusci, A. La Barbera, Luciano Pilloni, Daniela Pietrogiacomi, Canio Scarfiello, Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile (ENEA), Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement (RAPSODEE), IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Laboratoire de chimie de coordination (LCC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), 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), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), and 'Accordo di Programma Ministero dello Sviluppo Economico-ENEA', Project D3: Efficienza energetica nel settore industria
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Induction heating ,Materials science ,Ferromagnetic material properties ,Magnetic catalysis ,Steam reforming ,Ferromagnetic nanoparticles ,Pellets ,Energy Engineering and Power Technology ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,Methane ,Catalysis ,chemistry.chemical_compound ,Renewable Energy, Sustainability and the Environment ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,[CHIM.CATA]Chemical Sciences/Catalysis ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Fuel Technology ,chemistry ,Chemical engineering ,Particle-size distribution ,0210 nano-technology - Abstract
International audience; Ni60Co40 nanoparticles supported on γ-Al2O3 capable of simultaneously catalysing the steam reforming reaction of methane and supplying in-situ the heat necessary to activate the reaction by induction heating, have been synthesized and characterized. Energy is remotely and promptly supplied by an alternating radiofrequency magnetic field (induction heating system) to supported nanoparticles that act as dissipating agents by virtue of their ferromagnetic properties. The temperature reached on the Ni–Co based catalyst surface is high enough to obtain good catalytic performances for the steam methane reforming (SMR). By varying synthesis conditions, samples with two different metal loading (17 wt% and 30 wt%) and different particle size distribution were prepared and characterized. Experimental results evidence that the temperature reached on the catalyst surface is related to the metal loading and to the particles size distribution that strongly affect the ability of ferromagnetic nanoparticles to convert the externally applied radio frequency field into heat. Catalyst pellets proved their effectiveness reaching the temperature of 720 °C during SMR reaction and 80% methane conversion.
- Published
- 2021
18. Fine-tuning synthesis of fluorescent silver thiolate nanoclusters
- Author
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Kshitij Khanna, Luciano Pilloni, Martina De Angelis, Ludovica Primitivo, Daniela Caschera, Lorenza Suber, and Giuliana Righi
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Thermogravimetric analysis ,Materials science ,Infrared ,Biomedical Engineering ,atomic precise silver nanoparticle ,Bioengineering ,02 engineering and technology ,engineering.material ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Fluorescence spectroscopy ,Nanoclusters ,Nanomaterials ,Scanning transmission electron microscopy ,General Materials Science ,synthesis silver thiolate nanocluster ,fluorescent silver thiolate nanocluster ,monolayer protected silver nanoparticle ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Fluorescence ,0104 chemical sciences ,engineering ,Noble metal ,0210 nano-technology - Abstract
Noble metal thiolate nanoclusters are a new class of nanomaterials with molecular-like properties such as high dispersibility and fluorescence in the visible and infrared spectral region, properties highly requested in biomedicine for imaging, sensing and drug delivery applications. We report on three new silver phenylethane thiolate nanoclusters, differing for slight modifications of the preparation, i.e., the reaction solvent and the thiolate quantity, producing changes in the nanocluster composition as well as in the fluorescence behavior. All samples, excited in the range 250–500 nm, emit around 400 and 700 nm differing in the emission maxima and behavior. The silver thiolate nanoclusters have been characterized by way of C, H, S elemental analyses and Thermal Gravimetric Analysis (TGA) to determine the nanocluster composition, Scanning Transmission Electron Microscopy (STEM) to investigate the nanocluster morphology and UV-Vis and fluorescence spectroscopy to study their optical properties.
- Published
- 2021
19. ZnS wurtzite ceramic fabrication by a simple and cost‐effective pressureless sintering method: A microstructure development overview
- Author
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Radenka Krsmanovic Whiffen, Elena Salernitano, Selene Grilli, Giuseppe Magnani, Francesca Mazzanti, Luciano Pilloni, and Amelia Montone
- Subjects
grain size ,density ,ZnS ,SEM ,microstructure ,ceramics ,Two-step sintering - Abstract
The Two-Step Sintering (TSS) process is a useful method to obtain sintered materials of high density and to limit the grain growth associated with the final stage of the sintering process. One of the main advantages of this method is the lowering of the sintering temperature. The development of bulk, dense and small grain size in the wurtzite phase of the ZnS ceramic was investigated by using a micron-sized ZnS powder as a precursor material. The microstructure and morphology of the TSS-fabricated ZnS ceramic pellets were observed by Scanning Electron Microscopy (SEM) and compared to those produced by the conventional sintering process. The ZnS ceramic produced using the TSS method at 1100°C showed comparable density and a much finer microstructure (five times smaller grain size) than the ZnS ceramic produced using conventional sintering at 1250°C. It was demonstrated that the TSS process is a pressureless, simple and cost‐effective sintering method, able to deliver high density bulk, wurtzite phase ZnS ceramics with controlled grain size.  
- Published
- 2020
20. Electron Microscopy study of nanocrystalline wurtzite ZnS produced via a co-precipitation technique and its pyroelectric ceramics processed by 2-step- pressureless sintering
- Author
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Radenka Krsmanovic Whiffen, Loris Pietrelli, Luciano Pilloni, Giuseppe Magnani, Elena Salernitano, Selene Grilli, Francesca Mazzanti, and Amelia Montone
- Subjects
zinc sulfide ,two-step sintering ,wurtzite ,electron microscopy ,pressure-less sintering ,ceramics ,7. Clean energy ,ZnS nanopowder - Abstract
The pyroelectric performances of non-ferroelectric pyroelectrics like wurtzite- based materials (e.g. AlN, GaN, CdS or ZnO) make them important, although not widely used, compared to the current state-of-the-art ferroelectrics. Their high chemical and thermal stability allows their use at high temperatures in air, whereas ferroelectrics become ineffective when heated beyond their Curie temperature (TC). Wurtzite based materials have a higher thermal conductivity allowing them to react faster to ambient temperature changes, their raw material costs are lower and many of them are eco-friendly. Current pyroelectrics applications are limited to portable systems or tasks needing only μW–mW power. To be commercially viable, we must improve the current low efficiency of pyroelectric systems and intrinsically enhance the pyroelectric properties of modern materials through suitable doping or material engineering. We chose to study hexagonal wurtzite phase of ZnS, among the structurally simplest of pyroelectrics, as a possible energy harvesting material. An easy synthesis method – a co-precipitation technique, was tailored for nanocrystalline wurtzite ZnS production. This method is easy to scale-up and our next step is to build an in-house pilot plant that will produce substantial amounts of wurtzite ZnS nano-powder in an environmentally friendly and cost-effective manner. We further investigated the development of bulk, dense pyroelectric ceramics by the Two-Step Sintering (TSS) fabrication process, using as the precursor material both a micron-sized commercial powder of the ZnS cubic and hexagonal phases mixture, and an in-house produced wurtzite ZnS nanopowder. The TSS was chosen as being a pressureless, simple and cost‐effective sintering method for obtaining high density materials with controlled grain growth operating at a lower temperature than the conventiona process. Electron Microscopy techniques helped us to study the microstructure and morphology of both the precursor nanopowders and the obtained ceramics. Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 797951.
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- 2020
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21. ZnS wurtzite via the Two-Step Sintering process: effects on ceramic density and microstructure
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Elena Salernitano, Selene Grilli, Radenka Krsmanovic Whiffen, Giuseppe Magnani, Francesca Mazzanti, Amelia Montone, and Luciano Pilloni
- Subjects
zinc sulfide ,pressure-less sintering ,wurtzite ,two step sintering ,ceramics ,7. Clean energy - Abstract
Pyrolectric materials are able to harvest energy both from naturally and artificially occurring temperature changes. These materials could be the right way to recover some of the enormous amount of energy wasted as heat and help to develop new devices for harvesting thermal ambient energy. In this work it was investigated the development of bulk, dense pyroelectric ceramics, ideally with a highly developed texture and small grain size, using a micron-sized powder of the ZnS wurtzite phase as precursor material. The Two-Step Sintering (TSS) process is a useful method to obtain high sintered density and to limit the grain growth associated with the final stage of the sintering process. One of the main advantages of this method is the lowering of the sintering temperature. The microstructural, morphological and electrical properties of TSS-ZnS were determined and compared to ZnS produced by the conventional sintering process, performed at 1250°C. TSS-ZnS showed comparable density and a finer microstructure than conventional ZnS (five times lower grain size). It was demonstrated that the TSS process is a pressureless, simple and cost‐effective sintering method to obtain high density materials with controlled grain growth, without using a dopant or binder. The TSS produced ZnS ceramic was tested for pyroelectric energy harvesting. It is expected that the efficiency of the ceramic in harvested energy could be further improved by decreasing the grain size down to the nanoscale. Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 797951.
- Published
- 2020
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22. Cu nano-roses self-assembly from allium cepa, L., pyrolysis by green synthesis of C nanostructures
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Bruno Olivieri, Amanda Generosi, Fabio Di Pietrantonio, Gurumurthy Hegde, Lorenza Suber, Giancarlo Della Ventura, Barbara Paci, Luciano Pilloni, S. Supriya, Claudio Quaresima, Carlo Ottaviani, Paola De Padova, De Padova, P., Generosi, A., Paci, B., Olivieri, B., Ottaviani, C., Quaresima, C., Suber, L., Di Pietrantonio, F., Ventura, G. D., Pilloni, L., Supriya, S., Hegde, G., Di Pierantonio, F., Della Ventura, G., and Gurumurthy, G.
- Subjects
Materials science ,Allium cepa ,Green carbon nanostructures ,Scanning electron microscope ,Cu metallic nano-roses ,02 engineering and technology ,ED-XRD ,01 natural sciences ,lcsh:Technology ,lcsh:Chemistry ,symbols.namesake ,Phase (matter) ,General Materials Science ,Allium cepa, L., pyrolysis ,Spectroscopy ,Instrumentation ,Chemical composition ,lcsh:QH301-705.5 ,SEM/EDS ,Fluid Flow and Transfer Processes ,010405 organic chemistry ,lcsh:T ,Process Chemistry and Technology ,General Engineering ,021001 nanoscience & nanotechnology ,pyrolysis ,L ,lcsh:QC1-999 ,0104 chemical sciences ,Computer Science Applications ,Chemical engineering ,lcsh:Biology (General) ,lcsh:QD1-999 ,green carbon nanostructures ,Raman spectroscopy ,lcsh:TA1-2040 ,symbols ,Chemical stability ,Self-assembly ,0210 nano-technology ,lcsh:Engineering (General). Civil engineering (General) ,Pyrolysis ,lcsh:Physics - Abstract
Carbon nanostructures are achieved by bio-waste Allium cepa, L., (onion vulgaris) peels through pyrolysis at 900 °, C. They contain dispersed elements derived by their bio-precursors, like Mg, Ca, S, Na, K, and Cu. Here, we report the self-assembly of new Cu flower-shaped nanostructures organized as nano-roses. Remarkably, the nano-roses show rolled-up petals of Cu0 with a high chemical stability in air, exhibiting an intrinsic pure Cu crystalline phase. This suggests the exceptional potentiality to synthesize Cu0 nanostructures with novel physical/chemical properties. The size, morphology, and chemical composition were obtained by a combination of high-resolution scanning electron microscopy, energy dispersive X-ray spectroscopy, energy dispersive X-ray diffraction, and Raman spectroscopy.
- Published
- 2020
23. Linear β-amino alcohol catalyst anchored on functionalized magnetite nanoparticles for enantioselective addition of dialkylzinc to aromatic aldehydes
- Author
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Ludovica Primitivo, Alessandra Ricelli, Federica Di Pietro, Stefano Vecchio Ciprioti, Luciano Pilloni, Martina De Angelis, Lorenza Suber, Carla Sappino, Marika Iannoni, Francesco Righi, Giuliana Righi, Sappino, C., Primitivo, L., De Angelis, M., Righi, F., Di Pietro, F., Iannoni, M., Pilloni, L., Ciprioti, S. V., Suber, L., Ricelli, A., and Righi, G.
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asymmetric catalysis ,?-amino alcohols ,nucleophilic addition ,magnetite nanoparticles ,core-shell nanoparticles ,Ligand ,General Chemical Engineering ,Enantioselective synthesis ,Nanoparticle ,Alcohol ,General Chemistry ,linear b-amino alcohol catalyst ,addition of dialkylzinc to aldehydes ,Combinatorial chemistry ,Catalysis ,Magnetite Nanoparticles ,chemistry.chemical_compound ,chemistry ,Efficient catalyst ,Superparamagnetism - Abstract
A linear β-amino alcohol ligand, previously found to be a very efficient catalyst for enantioselective addition of dialkylzinc to aromatic aldehydes, has been anchored on differently functionalized superparamagnetic core-shell magnetite-silica nanoparticles (1a and 1b). Its catalytic activity in the addition of dialkylzinc to aldehydes has been evaluated, leading to promising results, especially in the case of 1b for which the recovery by simple magnetic decantation and reuse was successfully verified. This journal is
- Published
- 2020
24. Irradiation hardening and ductility loss of Eurofer97 steel variants after neutron irradiation to ITER-TBM relevant conditions
- Author
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Xiang Chen, Tim Graening, Dmitry Terentyev, Michael Rieth, Luciano Pilloni, Thak Sang Byun, Athina Puype, Josina W. Geringer, Steven J. Zinkle, Arunodaya Bhattacharya, Jean Henry, Jordan D. Reed, Yutai Katoh, Bhattacharya, A., Chen, X., Graening, T., Geringer, J. W., Reed, J., Henry, J., Pilloni, L., Terentyev, D., Puype, A., Byun, T. S., Katoh, Y., Rieth, M., and Zinkle, S. J.
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Neutron irradiation ,Materials science ,Eurofer97 steel ,Tensile properties ,Mechanical Engineering ,Metallurgy ,Indentation hardness ,Nuclear Energy and Engineering ,fracture ,Hardening (metallurgy) ,General Materials Science ,Reduction in area ,Tempering ,Irradiation ,Irradiation-hardening ,Elongation ,Ductility ,High Flux Isotope Reactor ,Civil and Structural Engineering ,Tensile testing - Abstract
Ten Eurofer97 steel variants, produced by non-standard fabrication-processing routes and modified alloying chemistries, were studied by neutron irradiations in the high flux isotope reactor. The irradiations were performed to ITER-TBM relevant conditions of ∼255–350 °C, 2.94–3.24 dpa. We quantified the irradiation-induced degradation of the steels using mechanical property tests. All the steels suffered from irradiation hardening, where a significant increase in Vickers microhardness and yield stress (σYS) occurred, accompanied with severe loss of tensile elongation. The extent of hardening was material dependent. For Tirr = 300±30 °C, most steels showed σYS increase in the range of ∼30% to as high as ∼66%, except for a low temperature tempered steel with σYS increase below 15%. Despite large losses in elongation, most failures were ductile. Significant post-necking ductility was retained with reduction in area (RA) between 65–75%, but
- Published
- 2021
25. Technological aspects in blanket design: Effects of micro-alloying and thermo-mechanical treatments of EUROFER97 type steels after neutron irradiation
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Gerald Pintsuk, Pilar Fernández, A. Puype, Tim Gräning, D. Terentyev, G. Aiello, Arunodaya Bhattacharya, Xiang Chen, E. Simondon, Luciano Pilloni, Jordan D. Reed, Yutai Katoh, Jean Henry, Mikhail A. Sokolov, H.-C. Schneider, Lance Lewis Snead, C. Cristalli, Josina W. Geringer, Michael Klimenkov, O. Tassa, Michael Rieth, Rieth M., Simondon E., Pintsuk G., Aiello G., Henry J., Terentyev D., Puype A., Cristalli C., Pilloni L., Tassa O., Klimenkov M., Schneider H.-C., Fernandez P., Graning T., Chen X., Bhattacharya A., Reed J., Geringer J.W., Sokolov M., Katoh Y., and Snead L.
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Materials science ,Mechanical Engineering ,fracture toughne ,Metallurgy ,EUROFER97 ,Fracture mechanics ,Fractography ,Blanket ,Microstructure ,post irradiation examination ,embrittlement ,Nuclear Energy and Engineering ,Operating temperature ,Ultimate tensile strength ,General Materials Science ,Irradiation ,thermo-mechanical treatment ,ddc:620 ,neutron irradiation ,Engineering & allied operations ,High Flux Isotope Reactor ,Civil and Structural Engineering - Abstract
Presently available data on neutron irradiation damage raise doubts on the feasibility of using EUROFER97 steel for a water-cooled starter blanket in a DEMO reactor, since the ductile-to-brittle transition temperature (DBTT) increases significantly for irradiation temperatures below 350°C. The additional DBTT shift caused by H and He transmutation can only be estimated based on very few results with isotopically tailored EUROFER97 steel. Conservative calculations show that the DBTT of EUROFER97 steel could exceed the operating temperature in water-cooled starter blankets within a relatively short time period. This paper presents results from a EUROfusion funded irradiation campaign that was performed in the High Flux Isotope Reactor at Oak Ridge National Laboratory. The paper compares ten newly developed reduced activation ferritic-martensitic (RAFM) steels irradiated to a nominal dose of 2.5 dpa at 300°C. The post-irradiation experiments using Small Specimen Test Technology included hardness, tensile, and fracture mechanics tests combined with fractography and microstructure analysis are presented. Results show that micro-alloying EUROFER97-type steels influenced the mechanical properties but a dominating impact on irradiation damage resistance could not be identified. In contrast, specific thermo-mechanical treatments lead to better DBTT behavior. Discussion about irradiation response to heat treatment conditions is also given. Despite requiring data also at high dpa values, the results indicate that with these modified materials an increased lifetime and potentially also an increased operating temperature window can be achieved compared to EUROFER97.
- Published
- 2021
26. Ultrathin and stable Nickel films as transparent conductive electrodes
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I. Di Sarcina, Maria Luisa Grilli, Antonio Rinaldi, Angela Piegari, Simone Bossi, Luciano Pilloni, Pilloni, L., Rinaldi, A., Bossi, S., Di Sarcina, I., Grilli, M. L., and Piegari, A.
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Fabrication ,Materials science ,Scanning electron microscope ,Transparent electrodes ,chemistry.chemical_element ,Nanotechnology ,Nickel ,Metal films ,Materials Chemistry ,Surface roughness ,Transmittance ,Transparent conducting film ,business.industry ,Metals and Alloys ,Indium-free electrode ,Ultra-thin films ,Surfaces and Interfaces ,Indium-free electrodes ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,Metal film ,chemistry ,Electrode ,Ultra-thin film ,Optoelectronics ,business - Abstract
Ultrathin stable transparent conductive nickel films were deposited on quartz substrates by radio frequency sputtering at room temperature. Such films showed visible transmittance up to 80% and conductivity up to 1.8 × 104 S/cm, further increased to 2,3 × 105 S/cm by incorporation of a micrometric silver grid. Atomic force microscopy and scanning electron microscopy revealed quite compact, smooth and low surface roughness films. Excellent film stability, ease, fast and low cost process fabrication make these films highly competitive compared to indium tin oxide alternative transparent conductors. Films were characterized regarding their morphological, optical and electrical properties. © 2015 Elsevier B.V.
- Published
- 2015
27. Austenitization and tempering temperatures effects on EUROFER97 steel
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Claudio, Testani, DI SCHINO, Andrea, Laura, Alleva, and Luciano, Pilloni
- Published
- 2018
28. Development of innovative steels and thermo-mechanical treatments for DEMO high operating temperature blanket options
- Author
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L. Bozzetto, O. Tassa, R. Sorci, Luciano Pilloni, L. Masotti, C. Cristalli, Masotti, L., Pilloni, L., and Cristalli, C.
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Nuclear and High Energy Physics ,Materials science ,Materials Science (miscellaneous) ,Alloy ,Ausforming ,engineering.material ,Blanket ,7. Clean energy ,01 natural sciences ,010305 fluids & plasmas ,Carbide ,Operating temperature ,0103 physical sciences ,Tensile ,Tempering ,Charpy ,010302 applied physics ,Metallurgy ,Creep ,EUROFER 97 ,Thermo-mechanical treatment ,RAFM steels ,lcsh:TK9001-9401 ,Nuclear Energy and Engineering ,engineering ,Hardening (metallurgy) ,lcsh:Nuclear engineering. Atomic power - Abstract
Among the options currently taken into account for the realization of the first DEMO reactor there are the “helium-cooled” and the “dual coolant” breeding blanket. Therefore the high temperature (650 °C) behavior of the proposed innovative martensitic alloys should be improved, namely the frame of the hereby reported activities is the development of martensitic alloys more resistant to creep, suitable to tolerate such a high operating temperature. In order to improve the high temperature mechanical properties, concerning the alloy design strategies, two alternative routes are proposed; the effect of Nitrogen and Tungsten increase are taken into account as well as the addition of carbo-nitride forming elements, like Vanadium, combined with the “ausforming” thermo-mechanical treatments. Two alloys have been designed and a special thermo-mechanical treatment on Eurofer 97-2 is proposed. The “ausforming” treatment, consisting in a sort of hot-working at a lower temperature with respect to the austenitization one after the austenitization stage, is aimed at the achievement of a beneficial dislocation “pinning” at high temperature due to carbide precipitation. Generally the improvement of tensile properties is associated to the hardening of the steel due to dislocation network and precipitation effects. This hardening is accompanied by a DBTT increase to markedly higher values with respect to Standard Eurofer. The proposed materials should be, in any case, at least room temperature ductile in order to undergo safe manufacturing and assembling processes. Therefore the issue of the DBTT increase has been taken into account by tuning the tempering temperature adequately. The two variations from chemical composition of Eurofer 97 have been casted and the thermo-mechanical treatments have been selected by means of SEM and hardness measurements to tune grain size and precipitation of carbides. The outcomes of the preliminary mechanical characterization (tensile, creep and impact tests) will be discussed in this paper. Keywords: EUROFER 97, RAFM steels, Thermo-mechanical treatment, Ausforming, Tensile, Creep, Charpy
- Published
- 2018
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29. Nanocluster superstructures or nanoparticles? the self-consuming scaffold decides
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Boby Joseph, Luciano Pilloni, Daniela Caschera, Patrizia Imperatori, Alessio Mezzi, Lorenza Suber, Saulius Kaciulis, Gaetano Campi, Antonella Iadecola, Nicola Angelini, and Pilloni, L.
- Subjects
X-ray absorption spectroscopy ,Materials science ,Ag nanoparticles ,Nanoparticle ,02 engineering and technology ,Reaction intermediate ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,nanocluster fluorescence ,nanocluster 2D superstucture ,0104 chemical sciences ,Nanoclusters ,X-ray photoelectron spectroscopy ,General Materials Science ,Lamellar structure ,0210 nano-technology ,Luminescence ,Ag nanoclusters - Abstract
We show that using the same reaction procedure, by hindering or allowing the formation of a reaction intermediate, the Ag+dodecanethiolate polymeric complex, it is possible to selectively obtain Ag dodecanethiolate nanoparticles or Ag dodecanethiolate nanoclusters in the size range 4-2 nm. Moreover, the Ag dodecanethiolate nanoclusters display a lamellar superstructure templated from the precursor Ag+dodecanethiolate polymeric complex. A plausible formation mechanism is illustrated where, starting from the precursor and scaffold lamellar Ag+ thiolate polymeric complex, first the nanocluster Agn 0 core is formed by reduction of isoplanar Ag+ ions, followed by Ag+ thiolate units that build protection, the nanocluster shell, around the core. The nanoclusters are characterized by elemental analyses, XRD, ATR-FTIR, XPS, XAS, MALDI, ESI, UV-Vis and fluorescence measurements. The luminescent Ag15(dodecanethiolate)11·2H2O nanocluster is achieved in good yield after 4 hours of reaction whereas after 2 hours, the luminescent Ag35(dodecanethiolate)16 is isolated. Both Ag nanoclusters present emission bands in the range 330-450 nm, the shifting depending on the excitation wavelength. This phenomenon is attributed to a possible dipolar state causing distribution in energies due to variability of dipole-dipole interactions. Moreover, both nanoclusters further present a NIR emission at about 700 nm independent from the excitation wavelength. Thanks to their optical and structural properties, the synthesized nanoclusters, perfect molecular/nanoparticle hybrids, have great potentiality for new applications in nanotechnologies. © 2018 The Royal Society of Chemistry.
- Published
- 2018
30. Effect of thermo-mechanical parameters on the mechanical properties of Eurofer97 steel for nuclear applications
- Author
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Andrea Di Schino, Claudio Testani, Luciano Pilloni, Testani, C., and Pilloni, L.
- Subjects
010302 applied physics ,Nuclear application steels ,Environmental Engineering ,Materials science ,Mechanical Engineering ,Aerospace Engineering ,02 engineering and technology ,mechanical properties ,quenching and tempering ,Engineering (General). Civil engineering (General) ,021001 nanoscience & nanotechnology ,7. Clean energy ,01 natural sciences ,13. Climate action ,0103 physical sciences ,mechanical propertie ,General Materials Science ,TA1-2040 ,Electrical and Electronic Engineering ,Composite material ,0210 nano-technology ,Thermo mechanical ,Civil and Structural Engineering - Abstract
Eurofer97 steel has been recognised in Europe as the reference steel for nuclear application under high radiation density. Following to this a detailed knowledge of microstructure evolution is required for such steel after thermo-mechanical processing. In this paper the effect of thermo-mechanical parameters on the mechanical behavior of Eurofer97 was investigated by hot rolling and heat treatment on pilot scale. Results show a strong effect was found of reheating temperature before rolling on the material hardness, due to an increase of hardenability following the austenite grain growth. A minor effect was found of the hot reduction and the tempering temperature in the total investigated deformation range. A loss of impact energy was found coupled with the hardness increase. © 2018 Andrea Di Schino et al., published by De Gruyter.
- Published
- 2018
31. Early failure of a locked titanium plate in a proximal humeral fracture: Case report and metallurgic analysis
- Author
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Luciano Pilloni, Fabrizio Donati, Michela Saracco, Giandomenico Logroscino, Corrado Piconi, and Pilloni, L.
- Subjects
Angular stability locking plate ,Metallurgic plate analysis ,Plate failure ,Proximal humerus fracture ,genetic structures ,lcsh:Surgery ,Critical Care and Intensive Care Medicine ,Article ,Locking plate ,Titanium plate ,03 medical and health sciences ,0302 clinical medicine ,Angular stability ,Medicine ,Orthopedics and Sports Medicine ,030212 general & internal medicine ,Early failure ,Old patients ,Orthodontics ,Metallurgic plate analysi ,030222 orthopedics ,Mechanical load ,business.industry ,Mechanical failure ,lcsh:RD1-811 ,Humeral fracture ,Emergency Medicine ,business - Abstract
Angular stability locking plates are commonly used in proximal humeral fractures, especially in old patients with osteoporotic bones. These implants show good results in short and midterm follow-up, but complications are not uncommon. Here we present a case report to describe a case of early failure of a proximal angular stability plate implanted in a 72 years old female with a highly unstable two part proximal humeral fracture. An optical and metallurgic analysis was also conducted to study the modalities of failure. We concluded that anatomic reduction and restoration of the medial cortical support are crucial in order to minimize the mechanical load on the bone–metal interface and to prevent mechanical failure, in particular when the fracture rim drop in the weak point of the plate that was found in the proximal two symmetric holes (Holes E). Keywords: Proximal humerus fracture, Plate failure, Angular stability locking plate, Metallurgic plate analysis
- Published
- 2018
32. High-Temperature Oxidation and Oxide Scale Formation in Plasma-Sprayed CoNiCrAlYRe Coatings
- Author
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Emanuele Serra, Luciano Pilloni, A. Brentari, C. Blasi, G. Di Girolamo, Serra, E., Pilloni, L., Blasi, C., and Di Girolamo, G.
- Subjects
Materials science ,Scanning electron microscope ,Metallurgy ,Metals and Alloys ,Oxide ,Energy-dispersive X-ray spectroscopy ,Atmospheric-pressure plasma ,Condensed Matter Physics ,Corrosion ,Superalloy ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,Porosity ,Thermal spraying - Abstract
MCrAlY coatings are usually adopted to improve the environmental resistance of Ni-based superalloy components of turbine engines against high-temperature oxidation and hot corrosion. In this work, CoNiCrAlYRe coatings were produced by atmospheric plasma spraying. The coatings exhibited relatively low oxygen content and porosity. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy analyses revealed that the high-temperature exposure at 1383ᅠK (1110ᅠᄚC) promoted the growth of an oxide scale on the top surface being composed of a continuous and dense Al2O3 inner layer followed by an outer mixed layer (Cr2O3 and spinels). The oxide scale was mainly composed of Al2O3, while the formation of mixed oxides occurred at lesser extent. After high-temperature exposure, the formation of internal oxides in some areas reduced the inter-lamellar cohesion, so that a decrease in microhardness was found.
- Published
- 2014
33. Pure magnetic hard fct FePt nanoparticles: Chemical synthesis, structural and magnetic properties correlations
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Gabriele Barrera, Luciano Pilloni, Lorenza Suber, Pierluigi Cossari, Federica Celegato, Marco Coïsson, Giada Marchegiani, Paolo Maria Eugenio Icilio Allia, F Padella, Paola Tiberto, Alessandro Chiolerio, E.S. Olivetti, and L Barba
- Subjects
Nanostructure ,Materials science ,Nanoparticle ,Nanotechnology ,Thermal treatment ,Magnetic nanoparticles ,FePt nanoparticles ,Hard magnetic materials ,Condensed Matter Physics ,Magnetic materials ,Nanostructures ,Chemical synthesis ,Powder diffraction ,Magnetic properties ,Particle aggregation ,Tetragonal crystal system ,Chemical engineering ,Phase (matter) ,Particle ,General Materials Science - Abstract
FePt nanoparticles, containing a near-equal atomic percentage of Fe and Pt, with a face centered tetragonal structure ( fct ), are challenging for potential applications in high performance permanent magnets and high density data storage. In this study, we report on the chemical synthesis, carried out both solvothermally and hydrothermally in autoclave reacting iron (III) acetylacetonate and platinum (II) acetylacetonate with tri- or tetra-ethylene glycol, these employed as solvents, reducers and particle surface protecting agents as well. In both methods, a subsequent thermal treatment at high temperatures is necessary to transform the magnetic soft face centered cubic ( fcc ) phase to the hard fct one. Organic low-weight molecules, generally used to protect the nanoparticle surface and avoid particle aggregation, are decomposed by the thermal treatment resulting in particle aggregation and coalescence phenomena; on the contrary, in this case, a polymer matrix is formed as particle protecting agent and, by thermally treating the hydrothermally prepared nanoparticles up to 750 °C for 1 h, the pure magnetic hard fct phase is obtained while preserving the nanostructure. A detailed study is carried out on FePt nanoparticle structure ( fcc and fct phases) and correlated to the magnetic properties of the system.
- Published
- 2014
34. Tuning hard and soft magnetic FePt nanocomposites
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Carla Cannas, Patrizia Imperatori, Saulius Kaciulis, Andrea Ardu, Davide Peddis, Em Bauer, A Notargiacomo, Alessio Mezzi, R Porwal, Lorenza Suber, Luciano Pilloni, and Pilloni, L.
- Subjects
Materials science ,Nanoparticle magnetic characterization ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Thermal treatment ,010402 general chemistry ,01 natural sciences ,Ion ,Phase (matter) ,Nanoparticle structural characterization ,Materials Chemistry ,Nanocomposite ,Rietveld refinement ,Mechanical Engineering ,Metals and Alloys ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Electron diffraction ,Chemical engineering ,Mechanics of Materials ,Multi-phase magnetic nanoparticle synthesis ,Atomic ratio ,0210 nano-technology ,multi-phase magnetic nanoparticle synthesis ,nanoparticle structural characterization ,nanoparticle magnetic characterization - Abstract
Nanocomposites formed by hard and soft magnetic phases are very promising for magnetic energy storage and biomedical applications. Highly challenging is the development of simple synthesis methods able to tune the phase composition and a thorough structural, morphologic and magnetic characterization in order to understand and optimize the interactions between hard and soft magnetic phases. Mainly depending on Fe:Pt atomic ratio, multi-phase or single phase FePt nanocomposites have been prepared by thermal treatment of core–shell FePt(Ag)@Fe 3 O 4 nanoparticles at 750 °C for 1 h under flow of a Ar + 5% H 2 gas mixture (H 2 is necessary to reduce Fe 2+ and Fe 3+ ions of Fe 3 O 4 to Fe 0 atoms and the thermal treatment to form the crystalline soft and hard magnetic FePt phases). Performing Rietveld refinement of the XRD data as well as HR-TEM and electron diffraction analyses, the different phases have been singled out. Besides single phase hard L1 0 FePt and soft magnetic L1 2 Fe 3 Pt nanoparticles, two phase soft α-FePt and γ-FePt and hard and soft magnetic L1 0 FePt and L1 2 FePt 3 nanocomposites have been formed and the structure and morphology correlated to their magnetic behavior. Moreover, for possible applications, it is important to form stable nanoparticle layers; as-prepared FePt(Ag)@Fe3O 4 nanoparticles have been chemically attached on a Si substrate, thermally annealed and the morphology, structure and magnetic properties of the layered nanoparticle sample investigated.
- Published
- 2016
35. Effect of growth parameters on the properties of RF-sputtered highly conductive and transparent p-type NiOx films
- Author
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Angela Piegari, Mehmet Yilmaz, Maria Luisa Grilli, Alberto Mittiga, Luciano Pilloni, P. Nunziante, Francesca Menchini, Theodoros Dikonimos, Piegari, A., Pilloni, L., Dikonimos, T., Menchini, F., Grilli, M. L., and Mittiga, A.
- Subjects
optical properties ,Materials science ,radio frequency sputtering ,Analytical chemistry ,chemistry.chemical_element ,nickel oxide ,02 engineering and technology ,01 natural sciences ,Oxygen ,X-ray photoelectron spectroscopy ,Electrical resistivity and conductivity ,Sputtering ,0103 physical sciences ,Materials Chemistry ,Transmittance ,Electrical and Electronic Engineering ,Total pressure ,010302 applied physics ,Partial pressure ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,optical propertie ,chemistry ,p-type transparent conductive oxide ,electrical properties ,0210 nano-technology - Abstract
Highly conductive and transparent NiOx films can be very useful as buffer layers for the optimization of the p-type contacts of optoelectronic devices. Thin NiOx films were fabricated by reactive radio frequency (RF) sputtering at room temperature starting from a Ni target. A systematic study of the influence of oxygen partial pressure, RF power and sputtering gas pressure on the films' properties was carried out. The structural, microstructural, optical and electrical properties were affected differently by the sputtering parameters. Resistivity decreased by increasing the oxygen partial pressure and the sputtering total pressure and by decreasing the RF power, while transmittance increased by decreasing the oxygen partial pressure and by increasing the RF power and sputtering pressure. Minimum resistivity of 1.6 × 10-2 Ωcm and a visible transmittance of 40% were achieved for a film grown in a pure oxygen atmosphere, while a higher transmittance of 54% and a resistivity of ρ = 1.1×10-1 Ωcm were obtained for a film grown at 30% oxygen partial pressure. The trends of transmittance and resistivity as a function of the oxygen pressure during the sputtering process can be explained in terms of the amount of Ni3+ defects deduced by x-ray photoelectron spectroscopy (XPS) measurements. The full interpretation of the other results is less straightforward and highlights the relevance of the samples' structural properties. © 2016 IOP Publishing Ltd.
- Published
- 2016
36. Microstructure and Wear Behavior of Plasma-Sprayed Nanostructured WC-Co Coatings
- Author
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Francesco Marra, Jacopo Tirillò, Luciano Pilloni, Giovanni Pulci, Giovanni Di Girolamo, Teodoro Valente, Pilloni, L., and Di Girolamo, G.
- Subjects
Marketing ,Materials science ,Decarburization ,Scanning electron microscope ,Metallurgy ,Atmospheric-pressure plasma ,Cermet ,Tribology ,Condensed Matter Physics ,Microstructure ,Indentation hardness ,Plasma sprayed ,Materials Chemistry ,Ceramics and Composites - Abstract
Atmospheric plasma spraying of WC-Co particles with standard gas mixtures (Ar-H2) typically results in largely decarburized coatings with relatively low wear resistance. To fabricate cermet coatings with enhanced tribological properties, nanostructured WC-Co coatings were plasma sprayed using two different process gas mixtures. Phase composition and microstructure were investigated by X-ray diffraction and scanning electron microscopy, respectively. Microhardness increased by increasing the amount of retained WC grains in coating microstructure. Friction and wear properties, measured under dry sliding conditions, strongly depended on the degree of decarburization. They were comparable to those of conventional coatings produced using identical conditions. © 2012 The American Ceramic Society.
- Published
- 2012
37. Preparation and characterization of close-packed nanostructured sol–gel ceria thin films prepared using cerium-sec-butoxide as precursor
- Author
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Maria Cristina Ferrara, Luciano Pilloni, Saverio Mazzarelli, Anna Maria Laera, Leander Tapfer, and Emanuela Piscopiello
- Subjects
Materials science ,Silicon ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,Substrate (electronics) ,Condensed Matter Physics ,Nanocrystalline material ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Cerium ,chemistry ,Chemical engineering ,Phase (matter) ,Materials Chemistry ,Ceramics and Composites ,Crystallite ,Thin film ,Sol-gel - Abstract
Polycrystalline, close-packed, homogeneous nanostructured ceria thin films were prepared by sol–gel process via dip-coating technique on soda-lime glass and (100)-oriented Si substrates. To produce the films, a sol was prepared using, as precursor, a home made cerium sec-butoxide dissolved in secondary butanol. The chemical composition, the microstructural/morphological characteristics and the optical properties of the coatings were investigated in detail. The experimental results clearly demonstrate that the ceria films are nanocrystalline (CeO2, cubic phase $$ {\text{Fm}}\bar{3}{\text{m}} $$ ) with an average grain size of about 2–3 nm for the samples grown on glass and of about 4–5 nm for the samples grown on silicon. The analyses of ceria layers grown on silicon show that the ceria coatings are free from organic residues and that a Si-oxide layer is formed at the film/substrate interface. The optical results evidence a red shift of the energy gap of about 0.5 eV that can be ascribed to conversion of relevant Ce4+ sites to Ce3+ sites and a consequent creation of oxygen vacancy at the surface of the ceria grains.
- Published
- 2011
38. Microstructural and thermal properties of plasma sprayed mullite coatings
- Author
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Luciano Pilloni, C. Blasi, Monica Schioppa, and Giovanni Di Girolamo
- Subjects
Materials science ,Process Chemistry and Technology ,Metallurgy ,Recrystallization (metallurgy) ,Mullite ,Thermal treatment ,engineering.material ,Microstructure ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,law.invention ,Differential scanning calorimetry ,Coating ,law ,Materials Chemistry ,Ceramics and Composites ,engineering ,Crystallization ,Composite material - Abstract
Thick mullite (3Al 2 O 3 –2SiO 2 ) coatings were fabricated by atmospheric plasma spraying (APS) in a mixture of crystalline and amorphous phases, as confirmed by X-ray diffraction (XRD) analysis. The coatings were isothermally heat treated in order to study recrystallization mechanism of the glassy phase. The morphology and the microstructure of both mullite feedstock and coatings were investigated by using scansion electron microscopy (SEM). The porosity of as-sprayed coating was in the range between 2 and 3% and substantially remained unchanged after thermal treatment. The thermal expansion of as-sprayed and annealed coatings was measured during heating up to the temperature of crystallization and the corresponding high-temperature extent of shrinkage was calculated. The differential scanning calorimetry (DSC) curves at different heating rates showed a sharp exothermic peak between 1243 and 1253 K, suggesting a rapid recrystallization of the amorphous phase. Finally, the heat capacity of recrystallized mullite coating was measured by DSC experiments. It was approximately 1.02 × 10 3 J/kg K at 373 K and increased with increasing test temperature.
- Published
- 2010
39. A metal hydride–polymer composite for hydrogen storage applications
- Author
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Franco Padella, Aurelio La Barbera, Marzia Pentimalli, Luciano Pilloni, and Enrico Imperi
- Subjects
chemistry.chemical_classification ,Materials science ,Renewable Energy, Sustainability and the Environment ,Hydride ,Composite number ,Alloy ,technology, industry, and agriculture ,Energy Engineering and Power Technology ,Polymer ,engineering.material ,Hot pressing ,Hydrogen storage ,Fuel Technology ,Nuclear Energy and Engineering ,chemistry ,Coating ,engineering ,Composite material ,Ball mill - Abstract
To address the issue of the breakdown into fine powders that occurs in the practical use of metal hydrides, the possibility of using a polymeric material as a matrix that contains the active metal particles was experimentally assessed. A ball milling approach in the tumbling mode was used to develop a metal hydride–polymer composite with a high metal to polymer weight ratio. The alloy powder was blended with the polymer and a coating of the metal particles was obtained. The composite was consolidated by hot pressing and the pellets were characterized in terms of their hydriding–dehydriding properties. The materials did not show significant losses in either loading capacity or kinetic properties. The polymeric matrix resulted as being stable under hydrogen cycling. Further, from SEM observation it was confirmed that the metal powders remained embedded in the polymeric matrix even after a number of cycles and that the overall dimensional integrity was retained.
- Published
- 2009
40. Microstructural and Kinetic Investigation of Hydrogen Sorption Reaction of MgH2/Nb2O5Nanopowders
- Author
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D. Mirabile Gattia, Annalisa Aurora, Amelia Montone, Luciano Pilloni, M. Vittori Antisari, E. Todini, and M. R. Mancini
- Subjects
Thermogravimetric analysis ,Materials science ,Hydrogen ,Scanning electron microscope ,Mechanical Engineering ,Magnesium hydride ,Composite number ,Analytical chemistry ,chemistry.chemical_element ,Sorption ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,Hydrogen storage ,chemistry ,Chemical engineering ,Mechanics of Materials ,General Materials Science - Abstract
MgH2/Nb2O5 composite is one of the most promising candidates for the hydrogen delivery. The performances of these materials are usually improved by mechanical milling because a finer distribution of the catalyst and the induction of defects on the particles accelerate the hydrogen sorption kinetic of the powders. Aiming at elucidating the factors responsible for this improvement, the effect on the reaction kinetics induced by nanometric and micrometric Nb2O5 powders has been investigated by a Sievert type apparatus. Nanometric additive imparts excellent performances in comparison to the micrometric one. The activation of the sample by sorption cycling has been investigated. In order to elucidate the role of the catalyst, a metallographic study of partially desorbed MgH2/Nb2O5 composite has been applied for the first time. The powders have been also characterized by X-ray diffraction and thermal gravimetric analysis.
- Published
- 2009
41. Scanning electron microscopy of partially de-hydrogenated MgH2 powders
- Author
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Marco Vittori Antisari, M. Rita Mancini, Daniele Mirabile Gattia, Luciano Pilloni, Annalisa Aurora, and Amelia Montone
- Subjects
Phase transition ,Materials science ,Microscope ,Scanning electron microscope ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,Nucleation ,General Chemistry ,Microstructure ,law.invention ,Hydrogen storage ,Mechanics of Materials ,law ,Desorption ,Materials Chemistry ,Sample preparation - Abstract
The sorption behavior of MgH2 is the subject of numerous investigations concerning the safe hydrogen storage in metallic hydrides. With the purpose of integrating kinetic studies on the MgH2–Mg phase transformation with the analysis of the local microstructure, we have developed an experimental method for the metallographic examination by Scanning Electron Microscopy of partially desorbed MgH2 powders. The setting of the microscope and the sample preparation procedure have been optimized for highest contrast between Mg and MgH2, based on different electron emissions. In these experimental conditions the two phases can be clearly detected even in critical condition when strongly scattering catalyst particles are present. The method has been tested on a set of ball milled MgH2 samples either pure or containing Fe as catalyzing agent. A complete information on the spatial distribution of all the phases constituting the sample can be obtained by integrating observations carried out at different primary beam energies with different signals. As far as the desorption behavior is concerned, SEM analysis shows that the MgH2–Mg phase transition is strongly affected by catalyst particles which, in the present case, appear to support the nucleation step in the phase transformation sequence.
- Published
- 2009
42. Tribological Characterization of WC-Co Plasma Sprayed Coatings
- Author
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Luciano Pilloni, Giovanni Pulci, Francesco Marra, and Giovanni Di Girolamo
- Subjects
Toughness ,Materials science ,Decarburization ,Metallurgy ,atmospheric plasma spraying ,cermet coatings ,high velocity oxygen fuel ,Atmospheric-pressure plasma ,Cermet ,Tribology ,engineering.material ,Microstructure ,Amorphous solid ,Coating ,Materials Chemistry ,Ceramics and Composites ,engineering - Abstract
Atmospheric plasma spraying of WC coatings is typically characterized by increased decarburization, with a consequent reduction of their wear resistance. Indeed, high temperature and oxidizing atmosphere promote the appearance of brittle crystalline and amorphous phases. However, by using a high helium flow rate in a process gas mixture, plasma spraying may easily be optimized by increasing the velocity of sprayed particles and by reducing the degree of WC dissolution. To this purpose, a comparative study was performed at different spray conditions. Both WC-Co powder and coating phases were characterized by X-ray difraction. Their microstructure was investigated by scanning electron microscopy. Mechanical, dry sliding friction, and wear tests were also performed. The wear resistance was highly related to both microstructural and mechanical properties. The experimental data confirmed that high-quality cermet coatings could be manufactured by using optimized Ar-He mixtures. Their enhanced hardness, toughness, and wear resistance resulted in coatings comparable to those sprayed by high velocity oxygen-fuel.
- Published
- 2009
43. Electro-deposition on carbon black and carbon nanotubes of Pt nanostructured catalysts for methanol oxidation
- Author
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Luciano Pilloni, L. Giorgi, Alessia Cemmi, Mauro Pasquali, Rossella Giorgi, Emanuele Serra, and C. Paoletti
- Subjects
Hydrogen ,Renewable Energy, Sustainability and the Environment ,electro-catalytic activity ,electro-deposition techniques ,pefcs ,pt electro-catalysts ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Carbon black ,Carbon nanotube ,Electrochemistry ,Catalysis ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Methanol ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Cyclic voltammetry ,Carbon - Abstract
An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon substrates (carbon black and carbon nanotubes), as an alternative way to prepare gas diffusion electrodes for polymer electrolyte fuel cells (PEFCs), is herein described. Pt nanoparticles well distributed and localized on the electrode surface were obtained by using an electric field. The electro-catalysts were prepared by single and multiple pulse galvanostatic polarizations in 1 M sulphuric acid + 5 mM exachloroplatinic acid solution. Chemical analysis, cyclic voltammetry and field emission gun scanning electron microscopy were used to determine the electrochemical features of Pt deposits and the influence of electro-deposition method on their nano-morphology. Electro-catalytic performances were studied by investigating the methanol oxidation reaction and the results are presented in form of surface specific activity and mass specific activity to take into account the electrochemical real surface and Pt loading. A comparison with commercial E-TEK Pt/C catalysts, prepared by traditional chemical reduction and heat treatment in hydrogen, shows that the electrodeposited catalyst presents higher activity at lower Pt loading.
- Published
- 2008
44. The influence of hydrogen on the fatigue behaviour of base and gas tungsten arc welded Eurofer
- Author
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Marie-Françoise Maday and Luciano Pilloni
- Subjects
Nuclear and High Energy Physics ,Materials science ,Hydrogen ,Metallurgy ,chemistry.chemical_element ,Welding ,Microstructure ,Fatigue limit ,law.invention ,Cracking ,Nuclear Energy and Engineering ,chemistry ,law ,General Materials Science ,Grain boundary ,Embrittlement ,Hydrogen embrittlement - Abstract
Room temperature hydrogen embrittlement susceptibility of Eurofer base-metal and gas-tungsten-arc-welded joint has been investigated by fully-reversed load-control low cycle fatigue. The tests were run on specimens subjected to electrochemical charging before and during cyclic stressing. Compared to the uncharged condition, increasing amounts of hydrogen in base-steel caused fatigue life reduction by promoting premature cracking of either grain boundaries or cleavage planes. Examination of fracture morphologies indicated that the underlying embrittlement mechanisms likely correlated with plastic flow alteration and interatomic bond decohesion, both induced by hydrogen. Specimen-to-specimen response variability by test replication was accounted for in terms of Eurofer material heterogeneity, based on relevant experimental indexes. This interpretation was consistent with the well known sensitivity to microstructure of hydrogen embrittlement processes, and explained the large scatter of fatigue lives and failure modes subsequently observed in equivalently charged Eurofer weld samples.
- Published
- 2007
45. Arc-Discharge Synthesis of Carbon Nanohorns and Multiwalled Carbon Nanotubes
- Author
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Daniele Mirabile Gattia, Luciano Pilloni, V. Contini, Marco Vittori Antisari, Renzo Marazzi, and Amelia Montone
- Subjects
Materials science ,Carbon nanofiber ,Mechanical Engineering ,chemistry.chemical_element ,Condensed Matter Physics ,Cathode ,Amorphous solid ,law.invention ,Electric arc ,Amorphous carbon ,chemistry ,Chemical engineering ,Mechanics of Materials ,law ,Carbide-derived carbon ,General Materials Science ,Carbon nanotube supported catalyst ,Composite material ,Carbon - Abstract
Carbon nanohorns and multiwalled carbon nanotubes have been synthesized by DC arcdischarge carried out at room pressure in air and Ar-enriched environment, by a specially designed experimental device. The resulting nanostructured material, characterized by electron microscopy and X-ray diffraction, shows different structures according to the condensation channels through which the sublimated carbon atoms are re-condensed in the solid state. Multi-Walled Carbon Nano- Tubes are mainly found in the hard crust formed at the cathode, while nano-horned particles can be recovered from a cylindrical collector surrounding the discharge. Further material, rag-like shaped and with an amorphous structure, can be collected in the reaction area. When the discharge occurs under Ar atmosphere, a larger quantity of this latter phase is synthesized. This suggests that the atmospheric oxygen could play an active role by burning the most reactive among the synthesized phases, like amorphous carbon contributing so to an “in situ” purification of the raw material.
- Published
- 2006
46. Hydrogen effects on the tensile and fatigue properties of Eurofer’97
- Author
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Luciano Pilloni and Marie-Françoise Maday
- Subjects
Materials science ,Yield (engineering) ,Mechanical Engineering ,Fatigue limit ,Brittleness ,Nuclear Energy and Engineering ,Ultimate tensile strength ,General Materials Science ,Deformation (engineering) ,Composite material ,Ductility ,Embrittlement ,Civil and Structural Engineering ,Hydrogen embrittlement - Abstract
Hydrogen embrittlement (HE) of Eurofer’97 was investigated by means of constant extension rate tensile (CERT) and fully reversed load-control low cycle fatigue (LCF) tests, run at room temperature and under electrochemical charging before and during specimen deformation. Increasing H content from 1.6 to 5.6 wppm caused increasing ductility loss compared to air behaviour and increasing data scatter from replicated CERT tests in terms of embrittlement indexes and fracture modes. The same trend manifested itself on Eurofer fatigue lifetimes after cyclic loading below the monotonic yield, but to a major degree as frequency was lowered. Fractographic analysis under scanning electron microscope indicated that brittle cracking, which macroscopically involved intergranular (IG) or transgranular (TG) separation, included morphologies closely related to HE phenomena through plastic flow modification and/ or interface decohesion. Correlation of these results with H desorption spectra and microstructural assessments suggested that the origin of mechanical response variability from specimen-to-specimen with similar H levels could arise from material heterogeneity in terms of trap characteristics.
- Published
- 2005
47. Carbon Nanotube Growth on PAN‐ and Pitch‐Based Carbon Fibres by HFCVD
- Author
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M.F. De Riccardis, Rossella Giorgi, D. Carbone, Nicola Lisi, E. Salernitano, Th. Dikonimos Makris, and Luciano Pilloni
- Subjects
Materials science ,Organic Chemistry ,chemistry.chemical_element ,Carbon nanotube ,Chemical vapor deposition ,Atomic and Molecular Physics, and Optics ,law.invention ,Nickel ,chemistry ,Impurity ,law ,Cluster (physics) ,General Materials Science ,Carbon nanotube supported catalyst ,Physical and Theoretical Chemistry ,Composite material ,Carbon ,Deposition (law) - Abstract
Carbon nanotubes (CNT) were grown on carbon fibres, both PAN‐ and pitch‐based, by hot filament chemical vapour deposition (HFCVD) using H2 and CH4 as precursors. Nickel clusters were electrodeposited on the fibre surfaces to catalyse the growth, and uniform CNT coatings were obtained on both PAN‐ and pitch‐based carbon fibres. Ni cluster features varied, depending on the deposition parameters, showing on average larger dimensions and denser distribution on pitch fibres. Multi‐walled CNTs with smooth walls and low impurity content were grown. The morphological features, both before and after the growth process, were characterised by SEM. This novel material based on carbon fibres coated with CNT, shows a potential for applications in polymeric matrix composites.
- Published
- 2005
48. Bias enhanced nucleation of diamond on Si(100) in a vertical straight hot filament CVD
- Author
-
Rossella Giorgi, E. Salernitano, Th. Dikonimos Makris, Luciano Pilloni, and Nicola Lisi
- Subjects
Silicon ,Chemistry ,Mechanical Engineering ,Nucleation ,Diamond ,chemistry.chemical_element ,General Chemistry ,Substrate (electronics) ,Chemical vapor deposition ,engineering.material ,Nanocrystalline material ,Electronic, Optical and Magnetic Materials ,Crystallography ,Chemical engineering ,X-ray photoelectron spectroscopy ,Materials Chemistry ,engineering ,Gas composition ,Electrical and Electronic Engineering - Abstract
The aim of the Bias Enhanced Nucleation (BEN) step is to increase the nucleation density during the CVD diamond growth process with respect to more traditional methods like scratching. Diamond seeds were grown in a HFCVD reactor with several vertical straight filaments and a double bias geometry allowing BEN over large area silicon substrates. The effect of the substrate temperature and the gas composition was studied. Spectroscopic and morphological characterisation has been performed on the substrates, both after the BEN and the subsequent growth process. The substrate temperature was found to be an important parameter controlling the nucleation. When the substrate temperature is above 1100 °C, both the nucleation and the growth resulted in nanocrystalline SiC while at lower temperature optimal diamond nucleation and growth were found. Simultaneously, intermediate phases between elemental and non-stoichiometric SiC were observed by XPS. Nucleation densities of 10 11 cm −2 and higher were obtained over a surface of several squared centimeters.
- Published
- 2005
49. Hydrogen Permeation Measurements on Alumina
- Author
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E. Serra, G. Cosoli, Luciano Pilloni, and A. Calza Bini
- Subjects
Arrhenius equation ,Hydrogen ,Analytical chemistry ,chemistry.chemical_element ,Atmospheric temperature range ,Permeation ,Thermal diffusivity ,Hildebrand solubility parameter ,symbols.namesake ,chemistry ,Permeability (electromagnetism) ,Materials Chemistry ,Ceramics and Composites ,symbols ,Solubility ,Nuclear chemistry - Abstract
The aim of this work is to measure the hydrogen transport and solubility parameters in the commercial alumina. Measurements are conducted using a time-dependent permeation method over the temperature range 1273–1673 K with hydrogen driving pressures in the range 104–105 Pa (100–1000 mbar). A half-power pressure dependence (diffusion-limited permeation) of the permeation flux for alumina is observed. The Arrhenius expressions for the hydrogen permeability, diffusivity, and Sieverts' constant values obtained from a fitting to the whole temperature range are as follows: P=3.3·10−10 exp(−97420/RT) mol·m−1·s−1·Pa−1/2 D=9.7·10−8 exp(−79990/RT) m2·s−1 Ks=5.5·10−3 exp(−22540/RT) mol·m−3·Pa−1/2
- Published
- 2004
50. Issues of low activation brazing of SiCf/SiC composites by using alloys without free silicon
- Author
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B. Riccardi, S Libera, Jörg Woltersdorf, Traian Petrisor, Luciano Pilloni, Eckhard Pippel, and C.A. Nannetti
- Subjects
Nuclear and High Energy Physics ,Materials science ,Silicon ,Metallurgy ,Alloy ,Intermetallic ,chemistry.chemical_element ,engineering.material ,Microstructure ,Carbide ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Silicon carbide ,engineering ,Brazing ,General Materials Science ,Composite material ,Eutectic system - Abstract
The paper presents a novel low activation brazing technique for SiCf/SiC composites. The brazing alloy does not contain free silicon and is based on the use of a Si–44Cr at.% eutectic and the intermetallic CrSi2 (melting temperatures 1390 and 1490 °C, respectively). These are advantageous because the melting point is low enough to avoid degradation of the advanced fibres and of the interphases in the composite, and the Si–Cr intermetallics are chemically compatible with silicon carbide. Both the eutectic and the intermetallic were prepared before brazing operations by melting a Si–Cr mixture. The joining was performed under vacuum (about 10−4 Pa). Systematic investigations of the microstructure and of the nanochemistry (TEM, EELS, ELNES) of the Si–Cr joints reveal that direct chemical Si–Si, Cr–C and Si–Cr bonds across the interface are responsible for the adhesion: the interfaces were proved to be nearly atomically sharp and adhesive. Altogether, this brazing procedure enables joints with sufficient strength and with a microstructure comparable with that of the starting powders to be obtained.
- Published
- 2004
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