18O diffusion coefficients were measured in some zinc oxide ceramics, using a secondary ion mass spectrometer. The results were interpreted as indicating extrinsic behavior. The values of the lattice diffusion coefficients with higher valence dopants compared with zinc ions were greater than lower valence dopant such as lithium ions. Using the data at deeper depth, the grain boundary diffusivity of oxide ions was also evaluated. Although the lattice diffusion coefficients varied in two orders of magnitude, the products of grain boundary width and grain boundary coefficient were less sensitive to the type of dopants.

Oxygen Grain Boundary Diffusion in Zinc Oxide Ceramics. Haneda, H., Sakaguchi, I., Watanabe, A., Tanaka, J.: Defect and Diffusion Forum, 1997, 143-147, 1219-24