Preparation and ionic transport properties of YDC-YSZ nanocomposites

The ionic transport properties of dense nanocomposites of yttria-doped ceria (YDC) and yttria-stabilized zirconia (YSZ), in a volume ratio of 1 : 1, have been investigated by electrochemical impedance spectroscopy. These materials were prepared by means of a fast-firing process starting from nanopowders with high specific surface area, avoiding the formation of secondary phases and minimizing the opportunity for grain growth to occur during sintering. An important enhancement of the total ionic conductivity with decreasing crystallite size was observed, as reported in the literature for other nanostructured ionic conductors. This result can be attributed to an almost ideal parallel connection between both nanophases, coupled to an increase of their grain boundary ionic diffusivity. In addition, it was proved that the presence of the YSZ phase significantly improves the mechanical properties of ceria-based nanoceramics.