Yttria-stabilized zirconia fast oxide-ion conducting ceramics were studied by using molecular dynamics methods. They were applied to symmetrical tilt grain boundaries, having the S = 5 (310)/[001] θ = 36.9º misorientation, in order to investigate the structures and dynamics of the interfaces. The simulations were performed on systems of 1920 atoms, at constant temperatures of up to 2673K. The atomic interactions were described by a simple pair potential model of Buckingham form. Structural relaxation produced an open structure which corresponded to the introduction of a row of Schottky defects that were adjacent, and parallel, to the interface. The diffusion of O along the boundary was observed at high temperatures, even without vacancies being explicitly introduced into the bulk by aliovalent doping. However, the diffusion rate was lower than that in single crystals of 8mol%Y2O3-stabilized zirconia. Further simulations demonstrated that the interfaces between perfect zirconia crystals were sources of resistance in the ionically conducting systems.

Molecular Dynamics Investigations of Grain Boundary Phenomena in Cubic Zirconia. C.A.J.Fisher, H.Matsubara: Computational Materials Science, 1999, 14[1-4], 177-84