Thermal behavior and phase transformation of ZrO2-10%SiO2 precursor powder prepared by a co-precipitation route without adding stability agent

Thermal behavior and phase transformation of ZrO2-10%SiO2 precursor powder prepared by a co-precipitation route without adding stability agent has been studied using different thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), nano beam electron diffraction (NBED), high-resolution TEM (HRTEM) and energy-dispersive X-ray spectrometer (EDS). The TG results show that four weight loss regions were from 298 to 443 K, 443 to 743 K, 743 to 793 K and 793 to 1400 K. The DTA result shows that the ZrO2 freeze-dried precursor powders crystallization at 1014 K. The activation energy of 993.7 kJ/mol was obtained for tetragonal ZrO2 crystallization using a non-isothermal process. The XRD result shows that only a single phase of tetragonal ZrO2 appears when the freeze-dried precursor powders after calcination between 1173 and 1373 K for 2 h. Moreover, when calcined at 1473 K for 2 h, the phase transformation from tetragonal ZrO2 fully converted to monoclinic ZrO2 occurred.