Conference Dates

November 8-12, 2015


The nucleation and growth of metallic particles within metal-doped oxides exposed to reducing conditions is relevant to the processing of materials for catalysts, fuel cells, and structural applications. Here, the precipitation of metallic nickel during the internal reduction of nickel-doped yttria stabilized zirconia (YSZ) is studied with electron microscopy and SQUID magnetometry. It is shown that the microstructure evolution proceeds in three distinct stages, each with its own kinetics description, dependent on the porosity and grain size. The transitions between stages depend on concentration gradients and electrostatic potentials that act upon the relevant transporting species, namely oxygen vacancies, electrons, nickel ions and zirconium vacancies. An understanding of these mechanisms enables the design of specific nanostructures