γ -Radiation synthesis of nanometer-size amorphous Cr2O3 powders at room temperature

Nanometer-size amorphous Cr2O3 powder with an average particle size of 6 nm has been prepared successfully by the γ-radiation method at room temperature from the solution containing Cr2O72− ions. Differential thermal analysis (DTA) shows that the crystallization temperature of amorphous Cr2O3 powder is about 300 °C. After heat treatment under vacuum at 500 °C for 44 h, amorphous Cr2O3 transformed to crystalline Cr2O3 with an average particle size of 15 nm. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).