Lead-free piezoelectric (1 – x – y)(Bi1/2Na1/2)TiO3–xBaTiO3–y(K0.5Na0.5)NbO3 (BNT–BT–KNN) ceramics were examined in situ under increasing temperature in the transmission electron microscope. Changing superstructure reflections indicate a transition from rhombohedral to tetragonal to cubic phase with broad coexistence regions. The additional evolution of the microstructure in combination with dielectric measurements leads to a model of two relaxor-type phase evolutions with temperature.
- In situ processing
- Niobium oxide
- Piezoelectric ceramics
- Transmission electron microscopy