Synthesis, characterization and microwave dielectric properties of nanocrystalline CaZrO3 ceramics

The synthesis, characterization and microwave dielectric properties of ceramic calcium zirconate (CaZrO3) nanoparticles synthesized by combustion process are reported in this paper. The X-ray diffraction studies confirm that phase formation is complete on annealing the as-prepared sample at 700 °C. The average particle size calculated from full wave half maximum (FWHM) using Scherer formula is ∼33 nm. The phase purity of CaZrO3 ceramic has been examined using differential thermal analysis (DTA), thermo gravimetric analysis (TGA) and Fourier transform of infrared spectroscopy (FTIR). The nanopowder was sintered at an optimized temperature1500 °C for 4 h and obtained about 98% of the theoretical density. The morphology of the sintered pellet was studied with scanning electron microscopy (SEM). The dielectric constant of 23.8, quality factor of (Qu × f) of 30600 GHz and a temperature coefficient of resonant frequency (τf) of 1.4 ppm/°C is observed at 5.65 GHz. The high quality factor and very low τf makes this sample suitable for microwave dielectric resonator applications.