Temporary reinforcement of ceria-based ceramics using chemical expansion and concomitant change in electrical properties

A ceria-based solid electrolyte was temporarily strengthened via the chemical expansion that occurred during contact reduction of its surface. One side of a non-doped ceria ceramic or 8 mol% samaria-substituted ceria ceramics was placed on a carbon sheet and heat-treated at various oxygen partial pressures and temperatures. Heat treatment increased the mechanical strength by up to 30%. The annealing temperature at which the samaria-substituted ceria had the highest strength was lower than that for the non-doped ceria. Both ceria ceramics had almost the same electrical conductivity regardless of whether they were untreated, subjected to contact reduction, or oxidatively heat-treated.