Effect of Thermal Treatment on the Formation, Textural and Electrical Conductivity Properties of Nanocrystalline Tb4O7.

Nanocrystalline Tb4O7 was fabricated by the calcination of its precursor, which was prepared by the precipitation method using NaOH as a precipitant. The phase changes accompanying the thermal treatment of the terbium parent were monitored using X-ray diffractometry (XRD) and thermogravimetry (TGA). The Calcination was performed over the temperature range of 300-700 degrees C. The texture of the produced nanocrystalline Tb4O7 samples was investigated using field-emission scanning electron microscopy (FE-SEM) and nitrogen adsorption measurements at -196 degrees C. Transmission electron microscopy (TEM) was used to determine the crystallite size of the obtained Tb4O7. The obtained results reveal that Tb4O7 with crystallites that measured 6-12 nm was formed at 400 degrees C. The crystallite size increased to 15-29 nm for the sample calcined at 700 degrees C. The electrical conductance properties of the different calcined samples were investigated over the temperature range of 150-500 degrees C. The electrical conductivity was observed to increase with the calcination temperature.