Diffusion in doped and undoped amorphous zirconia

[摘要] Grain boundaries in ZrO2 may act as favourable pathways for species, such as oxygen and hydrogen, which play an important role in corrosion when compared with volume diffusion through the bulk of the crystalline material. It is known that segregation of impurity and alloying elements can lead to highly-doped grain boundaries with amorphous structure. Here, these amorphous structures are compared to crystalline materials of equivalent composition. Atomic scale modelling methods have been used to anal-yse diffusion in undoped systems and zirconia cells doped with 5.3 at.% and 11.0 at.% of trivalent lan-thanide species. Diffusion coefficients, pre-exponential factors and activation energies are reported. Oxy-gen diffusivity was markedly increased in amorphous doped and undoped ZrO2 systems compared to equivalent undoped crystalline systems. Similar diffusivities are reported between amorphous and crys-talline doped systems at the concentrations considered. (C) 2021 The Author(s). Published by Elsevier B.V.

[发布日期] 2021-11-01

[关键词] ZrO2;Amorphous;Grain boundaries;Diffusion;Lanthanides