Combined effects of milling and calcination methods on the characteristics of nanocrystalline barium titanate

Barium titanate (BT) nanoparticles were synthesized by high-energy planetary milling technique. Wet milling and dry milling effects were compared. The milled powders were calcined at 1000 °C by microwave and conventional heating methodologies. The calcined powders were characterized by XRD, VP-SEM, EDX, BET, TGA and laser Raman spectroscopy techniques. Dry milled and microwave calcined BT showed the highest extent of tetragonality value of 1.021. VP-SEM micrograph confirmed the tetragonal morphology of microwave calcined BT(s) with an average grain size of 81 nm. Raman Spectra corroborated well with the XRD results. Wet milled and microwave calcined powders showed relatively higher residual hydroxyl ion contamination than that of the dry milled powders. Dry milled and microwave calcined powders showed superior room temperature dielectric constant value with relatively lower dielectric loss tangent value which are very much essential for the fabrication of multi layered ceramic capacitors.

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► Nano-barium titanate synthesized by wet and dry milling using barium hydroxide.
► Microwave and conventional heating effects were compared for process optimisation.
► Superior permittivities and lower grain sizes were obtained in microwave heated processes.
► Toluene used in the wet milling process had caused hydroxyl defects in the powders.
► Dry milling followed by microwave heating consumed relatively 7 times lesser energy.