Stable piezoelectric property of modified BiFeO3-BaTiO3 lead-free piezoceramics

Perovskite-structured 0.696BiFeO(3)-0.014Bi(Zn1/2Ti1/2)O-3-0.29BaTiO(3) (BF69.6-BZT1.4-BT29) lead-free piezoceramics with various MnO2 addition were prepared using a refined solid state reaction electroceramic processing. Powder X-ray diffraction measurements showed their crystallographic structure being of rhombohedral structure and scanning electron microscopy observations revealed that MnO2-doping enhances ceramic microstructure grain size growth. In contrast to BF-BT ceramics, low dielectric loss ceramics were obtained with combined strategies of refined electroceramic processing, Mn-doping and adding BZT third member. A good combination of ferroelectric and piezoelectric property was obtained in the 0.22 and 0.26 % in weight MnO2-doped BF69.6-BZT1.4-BT29 coarse-grained ceramics and discussed in relation to microstructure grain size effect and point defect effect. Excellent time and thermal aging stabilities of piezoelectric constant d (33) were also experimentally demonstrated and argued resulting from the feature of higher ferroelectric Curie temperature (T (C) ) and no ferroelectric-ferroelectric structural phase transition below T (C) of BF-BZT-BT system.