Combustion syntheses for BaTi4O9and PbxBa1–xTi4O9

Abstract

BaTi4O9and PbxBa1−xTi4O9, wherexis 0.1, 0.2, 0.3, 0.4, or 0.5, have been prepared by a combustion synthesis process. The process starts with spray drying aqueous solutions of Pb(NO3)2, Ba(NO3)2, TiO(NO3)2, and β-alanine with appropriate ratios. Combustion reactions occur when heating the spray-dried products to 300 °C, which convert them to BaTi4O9and PbxBa1−xTi4O9directly. PbxBa1−xTi4O9(x≧ 0.1) are low temperature, metastable phases and have not been reported before. Pb0.5Ba0.5Ti4O9is unstable above 800 °C and cannot be sintered. All PbxBa1−xTi4O9compositions will decompose by 1300 °C, the temperature for solid state synthesis of BaTi4O9. Single-phase PbxBa1−xTi4O9(x= 0.1, 0.2, 0.3, 0.4), however, have been sintered at relatively lower temperatures.