Characterization and sintering of BaZrO 3 nanoparticles synthesized through a single-step combustion process

Abstract

Barium zirconate (BaZrO 3) nanoparticles synthesized by a self-sustained single-step combustion process is reported in this paper. In this process, a phase pure nanopowder of BaZrO 3 has been obtained by the combustion of an aqueous solution containing Ba and Zr ions by using citric acid as complexing agent and liquor ammonia as fuel, thus giving rise to phase pure BaZrO 3 nanopowder in a single-step combustion without any further calcination. The X-ray diffraction studies have shown that the as-prepared powder was single phase, crystalline, and has a cubic perovskite structure (ABO 3) with a lattice constant a = 4.19 Å. The average particle size calculated from FWHM is ∼30 nm. The phase purity of BaZrO 3 nanopowder has been examined using differential thermal analysis (DTA), thermo gravimetric analysis (TGA) and Fourier transform of infrared spectroscopy (FTIR). The transmission electron microscopic investigation has shown that the particle size of the as-prepared powder was in the range 30–50 nm with a mean size of 40 nm. The nano BaZrO 3 has been sintered to a density of 99% of the theoretical density at 1650 °C in 2 h without the use of any sintering aids. The morphology of the sintered pellets has been studied with scanning electron microscopy (SEM). The dielectric constant ( ɛ r) and loss factor (tan δ) values obtained at 10 MHz for a well-sintered barium zirconate pellet has been found to be 32.2 and 1 × 10 −4, respectively, at room temperature.