Investigations on the synthesis, structural and microstructural characterizations of Ba_1-<i>_x</i>Sr<i>_x</i>ZrO₃ nanoceramics

Abstract

Strontium (Sr) substituted barium zirconate (Ba1-xSrxZrO3, for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) perovskite nanoceramics were prepared by simple, easy and cost-effective sol-gel auto combustion technique using citric acid as a fuel. X-ray diffraction (XRD) patterns confirmed the formation of cubic phase structure for x = 0.0–0.6 composition with minor impurity of carbonate. However, for x = 0.8–1.0 orthorhombic distorted perovskite structure was observed. The average crystallite size (t), lattice constant (a, b and c) and other structural parameters of Sr substituted barium zirconate nanoceramics were calculated from XRD data. The average particle size was calculated by using the Debye-Scherer's formula obtained to be 18–25 nm. The average crystallite size, lattice parameter, unit cell volume and X-ray density value changes when Sr2+ ions are substituted in BaZrO3 lattice, resulting in the structural variation. The microstructural studies were investigated through scanning electron microscopy (SEM) technique. SEM confirmed the homogeneous and well defined surface morphology of the synthesized samples in nano range. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of a metal oxide band (-O-Zr-O-) for all the calcined samples. The FTIR spectra confirmed that the prepared ceramics have a cubic perovskite structure for lower Sr composition, the shifting of the major band (for x = 0.8–1.0) suggests distortion in geometry. Compositional stoichiometry was confirmed by energy dispersive spectrum (EDS) analysis.