Synthesis of nanometer-sized PbZrxTi1-xO3 for gamma-ray attenuation

Abstract

Nanometer-sized PbZrxTi1-xO3 powder was fabricated by the tartrate precursor method with different Zr contents, x = 0, 0.25, 0.52, and 0.75. All samples were annealed at 850 °C. These annealed samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, and thermogravimetric analysis (TGA). The γ-ray attenuation coefficients of the annealed PbZrxTi1-xO3 samples were measured as a function of the Zr content for 661.7 keV γ-rays from a137Cs source. Positron annihilation spectroscopy was used to study the microstructural changes of the prepared samples. The XRD patterns indicate the presence of a tetragonal perovskite structure with a main peak corresponding to the (101) plane at 2θ of nearly 31°. The FTIR spectra show the presence of two absorption bands at around 620 and 390 cm−1, which are due to stretching and bending vibrations of the Ti–O bond, respectively. The nanometer-sized structure of synthesized PbZrxTi1-xO3 particles was confirmed by XRD and TEM. The TGA curves show a high decomposition temperature of more than 800 °C for PbZr0·52Ti0·48O3 and more than 650 °C for the other samples. PbZr0.52Ti0.48O3 shows the highest γ-ray mass attenuation coefficient among the samples studied. The positron annihilation lifetimes show that the main defect types are Pb monovacancies and Pb–O divacancies, and the samples with x ≥ 0.52 have the lowest average defect density. PbZr0.52Ti0.48O3 shows the highest value of the W parameter, which means that the chemical environment of its defects has more core electrons compared with the other samples. Finally, PbZr0·52Ti0·48O3 has novel properties for γ-ray shielding.