Electroceramic materials of tailored phase and morphology by hydrothermal technology

Hydrothermal technology was used to control the phase behavior and morphology of advanced electroceramics for applications as sensors, piezoelectrics, and low-loss dielectrics in microwave components. Conventional and microwave-assisted hydrothermal syntheses of perovskite-type ceramics NaNbO3, BaZrO3, BaHfO3, BaMg1/3Nb2/3O3, and also PbWO4, were carried out in temperatures varying from 80 to 260 degreesC, under saturated vapor pressure. Computer simulations were employed to minimize the trial-and-error mode of synthesis. The obtained powders were structurally and morphologically characterized by X-ray diffraction, scanning and transmission electron microscopies, thermal analysis, Fourier transform infrared spectroscopy, and nitrogen adsorption technique. The results showed that selecting the appropriate feed chemistry and processing conditions could tailor both phase behavior and morphology of the ceramic particles.