MD-Calculations of the Spinel Formation at the Alumina / Magnesia Interface
Keywords: Phase transformation, Gibbs Free Energy, Solid state transformation, Molecular Dynamics, Simulation, Interface energy, Reaction front migration, Spinel, Alumina, Magnesia.
Abstract Deposition of
Magnesia on (00.1) Alumina substrates forms a topotaxial (00.1)
[1
.0] Al2O3 / (111)[110]MgO
interface and subsequent heat treatment an epitaxial,
intermediate layer of MgAl2O4-spinel with
the orientation relationship (111)[110]. This solid-solid-phase
transformation reduces the misfit of the lattice parameters from
5.8% to 3.7% and is formed by the mutual cation diffusion of Mg2+
and Al3+, while the Oxygen sublattice remains nearly
unchanged. With Molecular Dynamics simulations the atomic
structure and the thermodynamic data, like Gibbs free energy,
interface energy and driving force of this system is calculated
using a new approach: The different, subsequent stages of the
phase transformation are calculated separately by an individual
input of supercells, which is admitted, because the result of the
transformation is know from the experiment.
Using the experience from these calculations this methode could be applied to calculate the interaction between two ceramic partciles.
Literature:
W.Wunderlich,
Molecular Dynamics Simulations of Al2O3-MgO-particles in order
to find reliable DEM-potentials, Proceedings of the 6th European
Conference on Rheology, Erlangen, Germany, Ed. H. Munstedt, J.
Kaschta, A.Merten (2002) 277-278, pdf-file 110kB
Keywords: Discrete Element model,
Interaction potential between ceramics particles, Surface Energy,
Debeye-Hueckel-Parameter
W.Wunderlich, M. Takahashi,
MD-Calculations about the Mg-Al-Spinel formation in the
sol-gel-process, Japanese Powder Science Society, Autumn Meeting
Bulletin, November 2000, S-11, 138-141 pdf-file 468kB
W.Wunderlich, Hideo Awaji
Molecular Dynamics Simulations of the fracture toughness of
Sapphire, Materials and Design [22] 1 (2001) 53-59 pdf-file 695kB
Keywords: Alumina,
Molecular Dynamics, Composite Materials, Fracture Toughness,
Crack propagation, Gibbs Free Energy, Surface Energy
W.Wunderlich, Hideo Awaji
Molecular Dynamics-Simulations of the fracture toughness of
Sapphire,
Progress of Theoretical Physics Supplement [138] (2000)
156-158, (Proc. Int. Conf. Computational Physics, ICCP5, Ed. by
Y. Hiwatari, Y. Oyanagi, Y. Okabe, H. Takayama) pdf-file
261kB
Keywords: Molecular
Dynamics, Thin Film, Atomic structure of interfaces, Surface
Energy
W.Wunderlich, Hideo Awaji
Molecular Dynamics Simulation of Spinel Formation at
Alumina/Magnesia: Building and confirming the model, Proc. Int.
Conf. Solid-Solid Phase Transf. `99 (JIMIC-3), Ed. by M. Koiwa,
K.Otsuka, T. Miyazaki, The Japan Inst. of Metals, ISBN4-88903-401-3
3057 (1999) 781-783 pdf-file 517kB
Keywords: Molecular
Dynamics, Thin Film, Atomic structure of interfaces, Surface
Energy
