Densification and microstructure of spark plasma sintered 7YSZ-Gd2O3 ceramic nano-composites

Spark plasma sintering (SPS) technique was used to densify 7 mol% yttria-stabilized zirconia (7YSZ) powder with Gd2O3-particles, at temperatures ranging between 1000 and 1200 °C. Fine dispersion of Gd2O3-particles into a full-densified matrix was achieved. Shrinkage and microstructure, as well as porosity were investigated. The fine Gd2O3-particles distributed into 7YSZ matrix have influence over the sintering consolidation and final microstructure. An increment in the spark plasma sintering temperature around 70 °C is detected when Gd2O3 particles are present. The thermal characterization was performed using the photothermal infrared radiometry technique. Both thermal diffusivity and thermal conductivity display a similar sigmoidal (Boltzmann type) behavior with the Gd2O3 concentration in the samples.