Preparations and characterizations of new mesoporous ZrO2 and Y2O3-stabilized ZrO2 spherical powders

In the absence of template and thermal stabilizer, novel mesoporous ZrO2 and Y2O3-stabilized ZrO2 (YSZ) spherical powders were synthesized via the improved spray reaction (SR) technique. The synthesized materials were characterized by thermo-gravimetry/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Nitrogen adsorption/desorption isotherm techniques. Results reveal that the microstructure of ZrO2 precursor significantly depends on the aging process, and the particle size, surface area and phase composition of prepared ZrO2-based materials significantly depend on the calcination temperature. For pure ZrO2 spherical particles, the size varies from 1.63 μm, 1.58 μm to 1.60 μm in correspondent to the calcined temperature 700 °C, 800 °C and 1000 °C, respectively. And also the major cubic ZrO2 (c-ZrO2) is formed when calcined at 700 °C whereas the predominant monoclinic ZrO2 (m-ZrO2) is synthesized when calcined at 800–1000 °C. For YSZ spherical particles, the size changes from 1.65 μm, 1.59 μm, 1.62 μm to 1.45 μm in correspondent to the calcined temperature 500 °C, 600 °C, 700 °C and 1000 °C, respectively. The synthesized YSZ spheres exhibit the similar phase constitution of predominant tetragonal ZrO2 (t-ZrO2) at all experimental temperatures but show the different surface area and pore diameter, ~ 14.72 m2/g surface area and 10.7 nm pore diameter at 500 °C as well as ~ 34.39 m2/g surface area and 8.3 nm pore diameter at 600 °C.