Piezoelectric ceramics based on Bi3TiNbO9 from mechano chemically activated precursors

Ceramics based on the Aurivillius type structure compound Bi3TiNbO9 were pr ocessed by natural sintering and hot pressing of amorphous precursors obtai ned by mechanochemical activation of oxides and carbonates mixtures. Synthe sis, grain growth and sintering take place in a single thermal treatment at moderate temperatures in comparison with ceramics processed from crystalli ne precursors. The influence of the processing parameters on the ceramic te xture and microstructure at mesoscopic scale were studied by XRD and quanti tative optical microscopy. It was possible to obtain both isotropic and tex tured ceramics. The occurrence of abnormal grain growth was observed under some conditions. An ample electrical characterisation of the ceramics was c arried out comprising dielectric, ferroelectric and piezoelectric propertie s. The influence of the microstructure on the properties and the interest o f the materials as high temperature piezoelectrics are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.