Influence of the synthesis route on the properties of BNBT ceramics

Abstract

BNBT (0.94[(Bi0.5Na0.5)TiO3]-0.06BaTiO3) nanopowders were prepared starting from an aqueous solution of inorganic salts (barium acetate, bismuth nitrate, sodium nitrate and titanium isopropoxide) either by the citrate-nitrate sol-gel combustion (SGC) or by spray drying (SD). Their chemical and microstructural properties were compared with the ones of the same system obtained by mechanical mixing of oxides (SSCO). The SD and SGC powders require temperatures 150 and 300°C lower than SSCO powder to form the perovskite phase. The chemical and physical properties of the obtained powders strongly depend on the considered chemical route. Therefore the subsequent sintering step and consequently the microstructure of the obtained ceramics differ significantly. The microstructures as well the piezoelectric properties of the sintered SGC, SD, SSCO samples are investigated and a critical comparison is presented.

Keywords

• Sol-gel combustion
• Spray drying
• Nanopowders
• Microstructure
• Piezoelectric characterization