BaTiO3-Based Lead-Free Electroceramics with Their Ferroelectric and Piezoelectric Properties Tuned by Ca2+, Sn4+ and Zr4+ Substitution Useful for Electrostrictive Device Application

Abstract

Dense microstructure BaTiO3 (BT) ceramic with c/a ~1.0144 and average grain size ~7.8 μm is developed by achieving the ferroelectric parameters Psat. = 24.13 μC/cm2 and Pr = 10.42 μC/cm2 with lower coercive field of Ec = 2.047 kV/cm. For BT ceramic, the “sprout” shape nature is observed for strain-electric field measurements with remnant strain ~ 0.212%, converse piezoelectric constant ~376.35 pm/V and electrostrictive coefficient Q33~ 0.03493 m4/C2. To tune the piezoelectric properties of BT ceramic, the substitutions of Ca2+ and Sn4+, Zr4+ are done for Ba2+ and Ti4+ sites respectively. The Ba0.7Ca0.3Ti1-xSnxO3 (x = 0.00, 0.025, 0.050, 0.075, and 0.1, BCST) system was studied with ferroelectric, piezoelectric and electrostrictive properties. The electrostrictive coefficient (Q33) ~ 0.0667 m4/C2 was observed for x = 0.075 and it is higher than the lead-based electrostrictive materials. Another (1-X) Ba0.95Ca0.05Ti0.92Sn0.08O3 (BCST) – (X) Ba0.95Ca0.05Ti0.92Zr0.08O3 (BCZT), ceramics (x = 0.00, 0.25, 0.50, 0.75, and 1) is studied. The BCST-BCZT ceramic system shows the increase of polymorphic phase transition temperatures toward the room temperature by Ca2+, Sn4+ and Zr4+ substitution. For BCST-BCZT system the composition x = 0.75 exhibits the d33, and Q33 values of 310 pC/N, 385 pm/V and 0.089 m4/C2 respectively which is greater than BT ceramics.