0000000000011236
AUTHOR
Gurcan Aral
Nanoscale oxide growth on Al single crystals at low temperatures: Variable charge molecular dynamics simulations
We investigate the oxidation of aluminum low-index surfaces [(100), (110), and (111)] at low temperatures (300-600 K) and three different gas pressure values. We use molecular dynamics (MD) simulations with dynamic charge transfer between atoms where the interaction between atoms is described by the Es+ potential composed of the embedded atom method (EAM) 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 ∼3 nm. The fitted curves allow us to determine the temperature and the pressure dependencies of the parameters i…
Oxidation of nanocrystalline aluminum by variable charge molecular dynamics
International audience; 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…
Molecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single crystals
The oxidation of aluminum single crystals is studied using molecular dynamics (MD) simulations with dynamic charge transfer between atoms. The simulations are performed on three aluminum low-index surfaces ((1 0 0), (1 1 0) and (1 1 1)) at room temperature. The results show that the oxide film growth kinetics is independent of the crystallographic orientation under the present conditions. Beyond a transition regime (100 ps) the growth kinetics follow a direct logarithmic law and present a limiting thickness of 3 nm. The obtained amorphous structure of the oxide film has initially Al excess (compared to the composition of Al2O3) and evolves, during the oxidation process, to an Al percentage …
Numerical Simulations on the Growth of Thin Oxide Films on Aluminum Substrates
We investigated the oxidation of nanocrystalline aluminum surfaces by using variable charge molecular dynamics at 600 K under three oxygen pressures: 1, 10 and 20 atm. The interaction potential was described by the electrostatic plus (Es+) model that allows dynamical charge transfer among atoms. We mainly focused on the effect of the oxygen pressure on the oxidation kinetic, the chemical composition and the microstructure of the oxide films formed. The results show that oxidation kinetics as well as chemical composition and microstructure depend on the applied oxygen pressure. The oxide film thickness tends to a limiting value equal to ~3 nm. Finally, we obtained a partially crystalline oxi…