A novel wet-chemical process to synthesise Ba(Mg1/3Ta2/3)O3 nanopowders

The present work proposes an easily operated and low cost wet-chemical process for the synthesis of Ba(Mg1/3Ta2/3)O3 (BMT) nanopowders. Tantalum pentaoxide, Ta2O5, was selected as the starting material, instead of the currently used TaCl5. The process involves the melting of the precursor Ta2O5 in the presence of sodium hydroxide followed by dissolution of the cooled glassy phase and washing several times with distilled water to remove the Na+ ions. A key step is the obtaining of a high quality Ta2O5·nH2O colloid by controlling the concentration of Ta ion during dissolution and washing processes. The fine BMT powders were then fabricated by mixing the colloidal Ta2O5·nH2O with barium acetate and magnesium acetate, according to the required molar proportions, followed by gelation and heat treatment. Nano BMT powders with an average particle size of 70 nm could be prepared at temperatures as low as 800 °C. In addition, the as prepared nanopowders revealed good sintering ability at low temperatures and the sintered nanoceramics exhibited excellent microwave dielectric properties.