Effect of titania and lithia doping on the boundary migration of alumina under an electric field

Boundary migration under an electric field was investigated for pure, TiO(2)-doped, and Li(2)O-doped Al(2)O(3) specimens. Boundary migration rates in TiO(2)-doped and Li(2)O-doped Al(2)O(3) specimens were much faster compared with that of pure Al(2)O(3). In all specimens, the migration rate was observed to depend on the applied bias direction. Compared with pure Al(2)O(3) the dependence of boundary migration on bias direction became more pronounced in TiO(2)-doped Al(2)O(3) but less pronounced in Li(2)O-doped Al(2)O(3). The results were explained in terms of the variation of grain sizes, mobility, and electrostatic potential of boundaries because of doping.