Electrical and hydrogen reduction enhances kinetics in doped zirconia and ceria: I. grain growth study

The kinetics of mass transport is central to ceramic processing and device stability. In this work, the effect of electrical and hydrogen reduction on the grain growth behavior of doped zirconia and ceria has been investigated. Faster grain growth has been observed under reducing conditions in all cases. The results firmly establish that a depressed local oxygen potential can enhance cation kinetics in fluorite-structured oxide ceramics. Meanwhile, a large electrical current can generate a sharp, spatially varied oxygen potential profile, creating a graded microstructure with a dramatic grain size transition across the length of the sample.