(Bi3TiNbO9)x(SrBi2Nb2O9)1−x aurivillius type structure piezoelectric ceramics obtained from mechanochemically activated oxides Original Research Article

Ferroelectric ceramics of (Bi3TiNbO9)x(SrBi2Nb2O9)1−x compositions are proposed in this work for use as high temperature piezoelectrics. Novel compositions with x>0.40 have been processed and studied. This type of compound grows in lamellar crystals, resembling their layered Aurivillius type structure, with the perovskite c-axis perpendicular to the major surfaces, which tend to pile up with the c-axis parallel to the applied pressure when ceramics are obtained by hot pressing. Such texture does not favor the ferro-piezoelectric properties. Isotropic ceramics with low porosity were processed by natural sintering of a mechanochemically activated oxide mixture. Optical microscopy and computer-aided image analysis and measurements were used in the characterization of the ceramic microstructure. Ceramics with transition temperatures in the range of 420°C≲Tt≲900°C can be obtained. Ferro-piezoelectric characterization shows that ceramics with x=0.60 present Tt=700°C, d33=11 pC N−1 and Kt=9.45%, which make them good candidates to be tested as high temperature piezoelectrics.