Effect of microwave heating during evaporation solvent and polymeric precursor formation in synthesis of BaZr0.08Ti0.92O3 nanopowders

The aim of this study was to verify the effect caused by microwave-assisted heating used during evaporation solvent and polymeric resin formation in the crystallization and final characteristics of BaZrxTi1-xO3 (BZT) nanopowders synthesized by the polymeric precursor - Pechini method. Using microwave heating, the syntheses were evaluated in acid and basic pH. For comparative effects, the syntheses using both pH were also carried out with conventional heating. Microwave heating allowed a reduction of more than 80% in the duration of the solvent evaporation and polymeric precursor formation steps compared to conventional heating at the same temperature. XRD and Raman spectroscopy confirmed the formation of a mixture of cubic and tetragonal perovskite structures with a high purity level of BZT. The most promising results were achieved, mainly when comparing the syntheses with basic pH, where BZT was crystallized at lower temperatures than those of conventional heating and acid pH achieved the highest degrees of crystallization and purity, as well as smaller average particle sizes. The calculated energy values for crystallization of the BZT synthesized by the microwave-assisted method were lower than those obtained by the conventional method. We also observed a favorable influence of microwave heating in obtaining smaller nanoparticles with uniform morphology and narrow particle distribution for this material, mainly for synthesis in basic pH.