Fenoelectric, piezoelectric and mechanical properties in lead free (0.5)Ba (Zr0.2Ti0.8)O3-(0.5)(Ba0.7Ca0.3)TiO3 electroceramics

Barium zirconate titanate barium calcium titanate [(0.5)BZT (0.5)BCT], a solid solution ceramic, was synthesized by solid state route and its structure, microstructure, dielectric, ferroelectric, piezoelectric and mechanical properties were investigated. Unipolar and bipolar strain loops with minimal hysteresis were observed from strain measurements. The d(33)* values increased with increase in electric field, reached a maximum of 1257 pm/V at a field of 0.6 kV/mm, subsequently decreased to 530 pm/V at a field of 4.1 kV/mm and showed slim hysteresis. A high value of dielectric constant (epsilon(r) similar to 9700) was recorded with the variation of frequency at a temperature around 85 degrees C (T-c) indicating frequency independent transition. P vs. E and I vs. E hysteresis measurements confirmed the intrinsic ferroelectric character with P-r of similar to 9.1 mu E/cm(2) and E-c of similar to 0.3 kV/mm. Polarization vs. electric field measurements at different electric fields showed slim and saturated hysteresis behaviour indicating a coarse grain structure. In the synthesized (0.5)BZT-(0.5)BCT, Vickers hardness, Young's modulus and fracture toughness were evaluated, and compared with those of lead based compounds and were found to be on par with them. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.