Abstract
The effect of the Lu-dopant configuration on oxygen shielding through Al2O3 wafers was investigated at 1923 K under oxygen potential gradients, where the oxygen permeation for the non-doped Al2O3 was controlled mainly by grain boundary diffusion of oxygen. The oxygen permeability constants of the wafers, in which Lu was either concentrated on the lower PO2 surface or segregated at grain boundaries in the wafers, were lower than that for the non-doped Al2O3 wafer. However, it was noteworthy that Lu concentrated on the higher PO2 surface obviously accelerated the oxygen permeation. Lu with dangling bonds on the top surface was presumed to attract the surrounding oxygen molecules and locally increase PO2 nearby the surface, resulting in acceleration of both oxygen and Al grain boundary diffusions.
