Evaluation of mechanochemically synthesized NiO/SDC composite nanopowders for the development of nanostructured cermet anodes

Composite powders containing 35% NiO, 50% and 65% NiO/SDC have been mechanochemically synthesized. These materials were characterized as existing as 10-20 nm crystallites of NiO and SDC in 50-75 nm agglomerates. Compaction and sintering was achieved at temperatures below 1200degreesC, yielding composite ceramics with intermediate densities whilst maintaining crystallite sizes below 50 nm. SEM showed that the microstructure consisted of a sub-micron distribution of NiO and SDC domains which upon closer inspection had a sub-structure with 20-70 nm features. Cermet formation at 400degreesC by reduction in H-2 was monitored by measuring the conductivity. The 60 vol% Ni cermet had the highest conductivity of 2.5 S/cm. The optimum Ni content for cermets fabricated was between 50 and 60 vol%.