ZrO2 powders were synthesized via sol-gel process using zirconium oxychloride octahydrate as the raw material. The effects of addition of glacial acetic acid and N,N-dimethylformamide (DMF) on crystal growth and chemical bond of powders were discussed. The structural evolution, phase transformation and morphological characteristic of powders were investigated by differential scanning calorimetric analysis (DSC). powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After adding the acetic acid and DMF, the crystallite size of ZrO2 decreased from about 26.48 to 13.94 nm when calcination at 600 degrees C for 40 min, and the activation energy for crystal growth reduced approximately from 7.76 +/- 0.62 to 2.74 +/- 0.28 kJ/mol in the initial stage, while abruptly increased to 26.48 +/- 1.09 kJ/mol in the later stage. The specific surface area decreased from 26.73 to 0.51 m(2)/g. Meanwhile, the metastable tetragonal phase could be stabilized in ZrO2 nanocrystals at 600 degrees C for 40 min. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.