MOLECULAR-DYNAMICS SIMULATIONS ON OXYGEN-ION DIFFUSION IN STRAINED YSZ CEO2 SUPERLATTICE/

Our earlier molecular dynamics results show that the construction of a strained yttria-stabilized zirconia (YSZ)/CeO2 superlattice considera bly enhances oxygen ion diffusion. In the present study, effect of sev eral parameters (e.g., Y2O3 concentrations, stacking periodicity, and temperature) on oxygen ion diffusion in strained YSZ/CeO2 superlattice were optimized to rationalize the understanding of the process mechan ism. We found that self-diffusion coefficient of O ions reaches a maxi mum at around 9.1 mol% Y2O3 concentration, and the increment of CeO2/Y SZ ratio enhances oxygen ion diffusion. Moreover, activation energy fo r oxygen ion diffusion in the YSZ/CeO2 superlattice (9 kcal/mol) was f ound to be lower than that observed in the bulk YSZ (15 kcal/mol). (C) 1998 Elsevier Science B.V. All rights reserved.