Mechanical properties of 1 mol% CeO2-10 mol% Sc2O3 co-doped and stabilized ZrO2 synthesized through hydro/solve-thermal method

Ultra-fine 1 mol% CeO2-10 mol% Sc2O3 co-doped and stabilized ZrO2 (1Ce10ScSZ) powders with average grain size less than 10 nm in diameter were prepared by hydro/solve-thermal method using either deionized water, ethanol, or methanol as solvent. As-synthesized powders were characterized in terms of phase structure, particle morphology, and chemical composition by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. Sintering studying was conducted on pellets of 15 mm in diameter and 3 mm in thickness under uniaxial compaction using 25 MPa at either 600, 800, 1000, 1100, 1200, 1400, or 1500 degrees C for 1 hour. Phase transitions and grain morphologies of those sintered samples were characterized by XRD and field emission scanning electron microscopy (FESEM). Mechanical properties were characterized on dense pellets sintered at 1500 degrees C by nanoindentation. Experimental results showed that ethanol was more effective to synthesize agglomerate-free 1Ce10ScSZ powders as compared with deionized water and methanol. Choice of solvent affected the environment of hydro/solvethermal solution, which led to variation of chemical compositions of powders and porosities of sintered pellets, and therefore, influenced their mechanical performance. Our study showed that solvent was important to make dense, thin, and mechanically robust 1Ce10ScSZ electrolyte for potential applications in electrochemical devices. Absolute values of hardness (H) and Young's modulus (E) measured from our samples are much higher and more consistence than those results obtained from commercial vendors reported in literatures.