Effects of NaCl raw material on structure and properties of (Bi0.5Na0.5)0.94Ba0.06Ti(O,Cl)3

Abstract

ABO3 perovskite ferroelectric ceramics were usually synthesized by using oxide and/or carbonate raw materials to form cation solid solutions. Here, we chose (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT) as a research objective, introduced NaCl to partly replace Na2CO3 as a raw material with a mole ratio x = 0–0.15, and investigated the structure and properties of the BNBTx ceramics. Upon increasing x, the phase structure deviates away from the rhombohedral–tetragonal morphotropic phase boundary toward the rhombohedral side. The remnant ferroelectric polarization Pr and piezoelectric coefficient d33 increase from 24.3 μC/cm2 and 102 pC/N at x = 0 to a maximum of 27.2 μC/cm2 and 117 pC/N at x = 0.06, then decrease sharply to 13.8 μC/cm2 and 55 pC/N at x = 0.15. Moreover, the maximum dielectric constant temperature Tm increases from 261 °C at x = 0–285 °C at x = 0.06 and then fluctuates, while the depolarization temperature Td decreases from 83 °C at x = 0 monotonously to 43 °C at x = 0.15. Such composition-dependent properties can be explained based on the anion solid solution of (Bi0.5Na0.5)0.94Ba0.06Ti(O,Cl)3, as affirmed by the Raman spectrum, which leads to competitive effects of suppressed oxygen vacancy and phase evolution on properties. This work provides an interesting attempt to develop an anion solid solution perovskite ferroelectric.