Piezoelectric ceramics based on Bi3TiNbO9 from mechanochemically activated precursors

Ceramics based on the Aurivillius type structure compound Bi3TiNbO9 were processed by natural sintering and hot pressing of amorphous precursors obtained by mechanochemical activation of oxides and carbonates mixtures. Synthesis, grain growth and sintering take place in a single thermal treatment at moderate temperatures in comparison with ceramics processed from crystalline precursors. The influence of the processing parameters on the ceramic texture and microstructure at mesoscopic scale were studied by XRD and quantitative optical microscopy. It was possible to obtain both isotropic and textured ceramics. The occurrence of abnormal grain growth was observed under some conditions. An ample electrical characterisation of the ceramics was carried out comprising dielectric, ferroelectric and piezoelectric properties. The influence of the microstructure on the properties and the interest of the materials as high temperature piezoelectrics are discussed.