Scandia-zirconia (ScZ) has a great technological interest for solid electrolyte applications due to the highest ionic conductivity among zirconia-based ceramics. However, ScZ usually requires high temperatures (> 1600 °C) to achieve 95% relative density by conventional sintering. Fully dense nanocrystalline ScZ specimens were obtained by recently proposed deformable punch spark plasma sintering technique (DP-SPS). It has been postulated that DP-SPS method inhibits grain growth due to the low processing temperatures and eliminates isolated residual pores due to high pressure application. Samples of ZrO2 containing 6 to 20 mol% Sc2O3 were synthesized by coprecipitation, calcined, and sintered by DP-SPS at low temperatures (700 to 800 °C) and high pressures (1.5 and 2 GPa). X-ray diffraction patterns only revealed a cubic single phase in polycrystalline samples with average grain size between 8 and 20 nm. In this work, grain size dependent phase transition and mechanical properties in nanostructured ScZ will be investigated by in-situ transmission electron microscopy (TEM). Phase transitions as a function of grain size will be investigated during coarsening by high temperature in-situ TEM. Mechanical properties will be determined via in-situ TEM nanomechanical testing and Hall-Petch relationship will be verified by changing grain size for a specific composition and polymorph. Sintered samples will be carefully prepared by focused ion beam. Considering that there is scarce information about microstructure of fully dense nanostructured (< 20 nm) ceramics in the current literature, results originated from this work will represent original data with relevant scientific contribution.
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