Abstract

Monophasic BaTi₄O₉ powder has been prepared by an auto-ignition route. The auto-ignition of the gel, prepared by thermal dehydration of a pH adjusted citrate–nitrate solution, directly resulted in voluminous BaTi₄O₉ powder with traces of carbonaceous material. Calcination of the voluminous powder at 600 °C produced pure nanocrystalline BaTi₄O₉ powder. Process parameters such as the amount of citric acid used for gelation and pH of the starting solution were found to have a signifant influence on the gel stability, temperature required for the phase formation and the powder characteristics. TEM micrographs revealed the nanocrystalline nature (crystallite size < 50 nm) of the powder. BaTi₄O₉ powder when cold pressed and sintered at 1200 °C for 6 hours in air reached ≈ 96% of its theoretical density.