Effect of Thermal Treatment on the Formation, Textural and Electrical Conductivity Properties of Nanocrystalline Tb<SUB>4</SUB>O<SUB>7</SUB>

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.