The influence of potential models on the structure and diffusion behavior of Al ₂ O ₃ ‐Na ₂ O‐K ₂ O amorphous systems

Abstract Molecular dynamics simulations were used to compare the effects of the Miyake and Guillot interatomic potentials on microstructure and ionic transport in an amorphous Al 2 O 3 ‐Na 2 O‐K 2 O system. Two interatomic potential models, Miyake and Guillot, are examined in detail. Both potentials reasonably predict the basic tetrahedral configuration of Al‐O. However, they differ in their ability to capture local structural characteristics. The Miyake potential provides bond lengths for K‐O, Al‐O, and Na‐O that closely match existing literature. It also demonstrates a broader bond‐angle distribution, reflecting the structural disturbances at elevated temperatures. In contrast, the Guillot model results in a quicker increase in coordination numbers and a more concentrated Al‐O‐Al bond‐angle distribution, indicating a more ordered short‐range structure. Analysis of the oxygen environment reveals that K + ions are more likely to break bridging oxygen bonds, leading to structural depolymerization. In comparison, Na + ions have a milder modifying effect. Regarding diffusion, the Miyake model shows that Na + ions generally diffuse faster than K + . However, under the Guillot potential, K + ions exhibit higher mobility;these differences also reflect the sensitive dependence of migration mechanisms on the potential in mixed Na‐K systems. Overall, the choice of potential significantly affects structure‐transport coupling and the ability to reproduce the mixed‐alkali effect in high‐temperature multicomponent amorphous oxides.