Ultrahigh Temperature in Situ Transmission Electron Microscopy Based Bicrystal Coble Creep in Zirconia I: Nanowire Growth and Interfacial Diffusivity

This work demonstrates novel in situ transmission electron microscopy-based microscale single grain boundary Coble creep experiments used to grow nanowires through a solid-state process in cubic ZrO2 between ≈ 1200 °C and ≈ 2100 °C. Experiments indicate Coble creep drives the formation of nanowires from asperity contacts during tensile displacement, which is confirmed by phase field simulations. The experiments also facilitate efficient measurement of grain boundary diffusivity and surface diffusivity. 10 mol% Sc2O3 doped ZrO2 is found to have a cation grain boundary diffusivity of Dgb=(0.056±0.05)exp(−380,000±41,000RT)m2s−1, and surface diffusivity of Ds=(0.10±0.27)exp(−380,000±28,000RT)m2s−1.