Dynamics of Oxidation of Aluminum Nanoclusters using Variable Charge Molecular-Dynamics Simulations on Parallel Computers

Campbell, Timothy J.; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Ogata, Shūji; Rodgers, Stephen L.

doi:10.1103/physrevlett.82.4866

Cited by 322 publications

(256 citation statements)

References 22 publications

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“…[44] techniques are available, but only selected publications are used here for comparison since the specification whether or not the sample material was oxygen saturated is crucial. Our samples are assumed to be oxygen saturated as the oxygen contamination of the surface is practically inevitable unless enormous effort is expended in the preparation of the experiment (e.g., vacuum transfer chamber) since a nanometer-thick oxide layer [42] will form immediately after exposure of the sample to regular air. Mills [25] data, based on a literature review by Keene, [43] have been suggested to represent oxygen saturated aluminum.…”

Section: F Surface Tensionmentioning

confidence: 99%

Thermophysical Properties of Liquid Aluminum

Leitner

Schmon³

et al. 2017

Metall Mater Trans A

152

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Ohmic pulse-heating with sub-microsecond time resolution is used to obtain thermophysical properties for aluminum in the liquid phase. Measurement of current through the sample, voltage drop across the sample, surface radiation, and volume expansion allow the calculation of specific heat capacity and the temperature dependencies of electrical resistivity, enthalpy, and density of the sample at melting and in the liquid phase. Thermal conductivity and thermal diffusivity as a function of temperature are estimated from resistivity data using the Wiedemann-Franz law. Data for liquid aluminum obtained by pulse-heating are quite rare because of the low melting temperature of aluminum with 933.47 K (660.32°C), as the fast operating pyrometers used for the pulse-heating technique with rise times of about 100 ns generally might not be able to resolve the melting plateau of aluminum because they are not sensitive enough for such low temperature ranges. To overcome this obstacle, we constructed a new, fast pyrometer sensitive in this temperature region. Electromagnetic levitation, as the second experimental approach used, delivers data for surface tension (this quantity is not available by means of the pulse-heating technique) and for density of aluminum as a function of temperature. Data obtained will be extensively compared to existing literature data.

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Section: F Surface Tensionmentioning

confidence: 99%

Thermophysical Properties of Liquid Aluminum

Leitner

Schmon³

et al. 2017

Metall Mater Trans A

152

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“…Oxidation of Al nanoclusters [19,20] or single-crystal surfaces of Al [21,22] for pressure ranging from 10 to 40 times the normal state were studied by variable charge molecular dynamics (VCMD) approaches. Under their oxidation conditions, these works clearly characterized the formation of an amorphous oxide layer.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…It was used to study nanocrystalline metal-oxide properties [16][17][18] or processes involved in the oxidation of metallic substrates [12,13,[19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of nanocrystalline aluminum by variable charge molecular dynamics

Perron

Garruchet

Politano

et al. 2010

Journal of Physics and Chemistry of Solids

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We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) simulations with the variable charge model that allows charge dynamically transfer among atoms. The interaction potential between atoms is described by the electrostatic plus (Es+) potential model, which is composed of an embedded atom method potential and an electrostatic term. The simulations were performed from 300 to 750K on polycrystalline samples with a mean grain size of 5 nanometers. We mainly focused on the effect of the temperature parameter on the oxidation kinetic. The results show that, beyond a first linear regime, the kinetics follow a direct logarithmic law (governed by diffusion process) and tend to a limiting value corresponding to a thickness of ~3nm. We also characterized at 600K the effects of an external applied strain on the microstructure and the chemical composition of the oxide films formed at the surface. In particular, we obtained a partially crystalline oxide films for all temperature and we noticed a strong correlation between the degree of crystallinity of the oxide film and the oxidation temperature.

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“…[31][32][33] Ogata and Campbell 31 and Campbell et al 32 have done the first variable charge MD simulations of oxidation of Al spherical nanoclusters where the thickness of the amorphous oxide film has been found to saturate at 3 to 4 nm. Gutierrez and Johansson 34 have investigated the structural properties of amorphous alumina ͑Al 2 O 3 ͒ using MD simulations with fixed atomic charges.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale oxide growth on Al single crystals at low temperatures: Variable charge molecular dynamics simulations

et al. 2006

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We investigate the oxidation of aluminum low-index surfaces ͓͑100͒, ͑110͒, and ͑111͔͒ at low temperatures ͑300-600 K͒ and three different gas pressure values. We use molecular dynamics ͑MD͒ simulations with dynamic charge transfer between atoms where the interaction between atoms is described by the Es+ potential composed of the embedded atom method ͑EAM͒ potential and an electrostatic contribution. In the considered temperature range and under different gas pressure conditions, the growth kinetics follow a direct logarithmic law where the oxide thickness is limited to a value of ϳ3 nm. The fitted curves allow us to determine the temperature and the pressure dependencies of the parameters involved in the growth law. During the adsorption stage, we observe a rotation of the oxygen pair as a precursor process to its dissociation. In most cases, the rotation aligns the molecule vertically to the Al surface. The separation distance after dissociation ranges from 3 to 9 Å. Atomistic observations revealed that the oxide presents a dominant tetrahedral ͑AlO 4 ͒ environment in the inner layer and mixed tetrahedral and octahedral ͑AlO 6 ͒ environments in the outer oxide region when the oxide thickness reaches values beyond ϳ2 nm.

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Dynamics of Oxidation of Aluminum Nanoclusters using Variable Charge Molecular-Dynamics Simulations on Parallel Computers

Cited by 322 publications

References 22 publications

Thermophysical Properties of Liquid Aluminum

Thermophysical Properties of Liquid Aluminum

Oxidation of nanocrystalline aluminum by variable charge molecular dynamics

Nanoscale oxide growth on Al single crystals at low temperatures: Variable charge molecular dynamics simulations

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