Karanam, A., Kumar, V., and Bichler, L., "Effect of SPS Process Parameters on the Densification Behaviour of Yttria Stabilized Zirconia," SAE Int. J. Mater. Manf. 7(2):406-410, 2014, doi:10.4271/2014-01-0835.
Zirconium dioxide (ZrO2) doped with Yttria exhibits superplastic behaviour, corrosion resistance and excellent ion conducting properties  at moderate temperatures and thus it can be used as an electroceramic to measure the pH of high temperature water used in fuel cells. Several fabrication processes are available for preparation of zirconia ceramics. This research focused on the study of using Spark Plasma Sintering (SPS) process to prepare Yttria Stabilized Zirconia (YSZ) ceramic.8 mol% YSZ was subjected to varying SPS sintering conditions. Samples were sintered by changing the heating cycle, dwell time, sintering pressure and cooling cycle. Subsequently, these parameters were related to the densification characteristics of the as-sintered YSZ. The results of specific gravity measurements and microstructure evaluation suggest that stepped heating followed by a slow cooling results in YSZ with highest relative density (99.9%).