Reflux synthesis and hydrothermal processing of ZrO2 nanopowders at low temperature

In this paper, we report on the reflux synthesis at 90 °°C and hydrothermal processing at 120 °°C for obtention of zirconium oxide (ZrO2) nanopowders under several conditions. These nanopowders were characterized by X-ray diffraction (XRD), Fourier transform Raman (FT-Raman) spectroscopy, adsorption–desorption N2-isotherms, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and field-emission scanning electron microscopy (FE-SEM). XRD patterns and Raman spectra indicated that ZrO2 nanopowders present a monoclinic structure. In addition, the hydrothermal processing promoted an increase in crystallinity of ZrO2 nanopowders. FT-IR spectra revealed a small shoulder on the νν (Zr–O) bands in transmittance spectra of the ZrO2 nanopowders. The decomposition of precursor was accompanied by evolution of TGA curves. The morphology of ZrO2 nanopowders was observed by FEG-SEM. Also, the FEG-SEM micrographs revealed that the presence of H2O2 in systems reduced the particle size, while the absence of promoted an increase in particle size.