Solute segregations at the space-charge layers of stabilized zirconia: An opportunity for ameliorating conductivity

According to a space-charge theory analysis, the space-charge potential of YSZ is negative, which corresponds to a V-0(..) depletion in the space-charge layer. An extremely low grain-boundary conductivity of the high-purity YSZ is thus explained. Under the condition that the bulk property is ensured by the optimal dopant additions, an idea of increasing the grain-boundary conductivity by the segregations of solutes with positive effective charge is put forward. The most likely driving force for the segregations is the elastic strain energy. And the feasibility of this idea has been proved by some experimental and theoretical results.