Powder Technology, Vol.227, 9-16, 2012
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 mu m, 1.58 mu m to 1.60 mu m in correspondent to the calcined temperature 700 degrees C, 800 degrees C and 1000 degrees C, respectively. And also the major cubic ZrO2 (c-ZrO2) is formed when calcined at 700 degrees C whereas the predominant monoclinic ZrO2 (mZrO(2)) is synthesized when calcined at 800-1000 degrees C. For YSZ spherical particles, the size changes from 1.65 mu m, 1.59 mu m, 1.62 mu m 1.45 mu m in correspondent to the calcined temperature 500 degrees C, 600 degrees C, 700 degrees C and 1000 degrees 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, similar to 14.72 m(2)/g surface area and 10.7 nm pore diameter at 500 degrees C as well as similar to 34.39 m(2)/g surface area and 8.3 nm pore diameter at 600 degrees C. (C) 2012 Elsevier B.V. All rights reserved.