Piezoelectric and dielectric properties of CeO2-doped Bi0.5Na0.44K0.06TiO3 lead-free ceramics

Abstract CeO 2 -doped lead-free Bi 0.5 Na 0.44 K 0.06 TiO 3 piezoelectric ceramics (0–1.0 wt%) were synthesized by conventional ceramics technique. X-ray diffraction shows that CeO 2 diffuses into the lattice of Bi 0.5 Na 0.44 K 0.06 TiO 3 to form a solid solution, but does not change the rhombohedral phase in Bi 0.5 Na 0.44 K 0.06 TiO 3 during sintering. The temperature dependence of dielectric constant ɛ r and dielectric loss tan δ measurement reveals that the solid solutions experience two phase transitions from ferroelectric to anti-ferroelectric and anti-ferroelectric to paraelectric, which can be proved by P – E hysteresis loops at different temperatures. The specimen containing 0.2 wt% CeO 2 shows that the coercive field E c decreases from 8.22 to 4.76 kV/mm while the remnant polarization P r decreases from 37.2 to 30.0 μC/cm 2 , corresponding to the enhancement of piezoelectric constant d 33 of 132 pC/N and electromechanical coupling factor k p of 27.8%.