Magnetoelasticity and internal strains in nanocrystalline nickel

Bonetti, E.; Campari, Enrico Gianfranco; Pasquini, Luca; Sampaolesi, E.; Scipione, Gabriella

doi:10.1016/s0965-9773(99)00242-1

Cited by 7 publications

(9 citation statements)

References 4 publications

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“…Moreover, they have revealed that in cases where strong magnetoelastic coupling exists, the peculiar distribution of the local microstrain significantly affects the elasticity moduli. 6 In the present paper, we report on a research on the anelastic behavior of ball-milled nanocrystalline aluminum and nickel. Particular emphasis is given to the correlation between the high temperature damping, the anelastic relaxation peaks and the nanostructure evolution.…”

Section: Introductionmentioning

confidence: 99%

Mechanical spectroscopy of nanocrystalline metals: Structure and anelastic behavior

Bonetti

Pasquini

1999

Journal of Elec Materi

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Nanocrystalline aluminum and nickel were prepared by mechanical attrition in a planetary ball-milling apparatus working under a 10 -4 Pa vacuum in the 150-300 K range. A detailed investigation of the mechanical behavior in the anelastic regime was accomplished by employing different mechanical spectroscopy apparatuses in the 0.01-10 3 Hz range. Measurements of the elastic energy dissipation coefficient and of the dynamic elasticity modulus as a function of temperature and frequency have shown an enhanced damping at low temperatures and an anelastic relaxation peak tentatively assigned to the short range dynamics at the interfaces. Moreover the magnetic field dependence of the dynamic elastic modulus in nickel revealed a strict correlation between the microstrains confined at the interfaces and the magnitude of the magnetoelastic coupling.

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Section: Introductionmentioning

confidence: 99%

Mechanical spectroscopy of nanocrystalline metals: Structure and anelastic behavior

Bonetti

Pasquini

1999

Journal of Elec Materi

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“…12 This method consists of the reaction between Ni(COD) 2 (where COD = cycloocta-1,5-diene) and Al(ethyl) 3 in toluene, which yields a black±brown dispersion. Hydrogen is used in this reaction as a means to hydrogenate the olefinic compounds of COD and ethylene.…”

Section: Catalyst Preparationmentioning

confidence: 99%

“…The particles were found to form aggregates of 100±500 nm; these were found to be comprised of smaller particles of 5±7 nm (X-ray diffraction (XRD) via Scherrer equation) and 2±5 nm (transmission electron microscopy). This approach is especially attractive for the preparation of skeletal catalysts, because with Ni(COD) 2 the nickel is already reduced and the Al(ethyl) 3 is not used as reducing agent but rather as a reaction partner for the Ni(0) complex. As a consequence of this, the stoichiometry of the reaction is not limited to a specific ratio.…”

Section: Catalyst Preparationmentioning

confidence: 99%

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Nanoscale skeletal nickel catalysts prepared via ‘bottom up’ method

Richards

Geibel

Hofstadt

et al. 2002

Applied Organom Chemis

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NiAl nanoparticles are of considerable importance because of interest in examining the effects of size, surface area, and composition on their physical and catalytic properties. Recently, a new method for the`bottom up' wet chemical preparation of nickel aluminides has been reported. The ability to leach the aluminum from this system provides an entrance to the preparation of skeletal-type metal catalysts similar to those produced in Raney-type systems. Furthermore, it is believed that these nanoparticulate catalysts should provide high surface areas and high activities, while the presence of aluminum within the bulk of these catalysts provides additional stability. Here, we present the results of studies conducted on this system which compare their properties and behavior with traditional bulk Raney nickel systems. Additionally, we show that we are able to alter the properties of these nanoparticles by changing the stoichiometric ratio of nickel and aluminum. The properties of all systems have been analyzed through the use of nitrogen adsorption, X-ray diffraction, and elemental analysis. Finally, the catalysts generated have been compared for their activity in the hydrogenation of butyronitrile.

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“…Several preparation techniques have been employed so far in order to obtain a bulk material [severe plastic deformation (Zhilyaev et al, 2002, and references therein), ball milling (Bonetti et al, 1999;Valiev et al, 1997) or inert gas condensation followed by compaction of nanocrystalline powders (Birringer et al, 1984)], thick films [direct or pulsed electrodeposition (Shriram et al, 2000;Palumbo et al, 1997;El-Sherik & Erb, 1995)] or thin films [physical vapour deposition methods, PVD (Knapp & Follstaedt, 2004;Zhong et al, 2004;Brunetti & Monticone, 1993;Hugo et al, 2003;Mitra et al, 2001Mitra et al, , 2004Gai et al, 2002;Hurley et al, 2005)]. Among the PVD methods of ncNi production, magnetron sputtering has been relatively seldom employed for the preparation of nc-Ni (Brunetti & Monticone, 1993;Hugo et al, 2003;Mitra et al, 2001Mitra et al, , 2004Gai et al, 2002;Hurley et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Structural study of nanocrystalline nickel thin films

et al. 2007

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Nickel thin films (400 nm) were deposited by magnetron sputtering onto fused silica substrates. The effects of argon pressure and substrate temperature (from room temperature to 973 K) upon the film structure were investigated. The film structure was studied using grazing‐incidence small‐angle X‐ray scattering (GISAXS) and X‐ray diffraction (XRD) analysis. It was found that the prepared nanocrystalline Ni films contain two kinds of inhomogeneities observable by GISAXS, namely isotropic and platelet‐like. Up to about 373 K the isotropic or spherical `particles' prevail, while above that temperature the platelet‐like `particles' predominate. These inhomogeneities are ascribed to intergranular matter or grain boundaries, since the grain size (as determined from the XRD patterns) was found to increase from 7 nm in samples deposited at room temperature to about 90 nm in samples deposited at 423 K or higher temperature.

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Magnetoelasticity and internal strains in nanocrystalline nickel

Cited by 7 publications

References 4 publications

Mechanical spectroscopy of nanocrystalline metals: Structure and anelastic behavior

Mechanical spectroscopy of nanocrystalline metals: Structure and anelastic behavior

Nanoscale skeletal nickel catalysts prepared via ‘bottom up’ method

Structural study of nanocrystalline nickel thin films

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