The effect of tantalum substitution on the microstructure and dielectric and piezoelectric properties of Pb_0.99(Zr_0.95Ti_0.05)_0.98Nb_0.02O₃ ceramics

Lead zirconate titanate (PZT95/5) based piezoelectric ceramics with the compositions Pb_0.99(Zr_0.95Ti_0.05)_0.98Ta_0.02O₃ (PZTT) and Pb_0.99−0.5x(Zr_0.95Ti_0.05)_0.98−xNb_0.02Ta_xO₃ (PZTN), where x = 0.0, 0.005, 0.010, 0.015 and 0.020 were synthesized using conventional solid state sintering at 1250 °C for 2 h in air. The effect of tantalum substitution on the microstructure, dielectric and piezoelectric properties of the samples were studied. The results showed that the Ta-doped samples had finer microstructures. The PZTT samples had microstructures with finer grains (average grain size of 3.80 µm) in comparison with the PZTN samples (average grain size of 5.33 µm). The relative densities of the PZTN and PZTT samples were approximately 94.1 and 94.4%, respectively. Moreover, the relative dielectric constant (ε_r), piezoelectric coefficient (d₃₁) and elastic compliance (S₁₁^E) of the samples reached the maximum values of 349, − 15.2 PC/N and 8.42 Pm²/N, respectively at 1.5 mol% tantalum substitution. Furthermore, the relative dielectric constant (ε_r), piezoelectric coefficient (d₃₃) and voltage coefficient (g₃₃) of the PZTN samples reached the optimal values of 306, 69 PC/N and 25.44 mV m/N, respectively, in comparison with the PZTT samples (329, 67 PC/N and 21.43 mV m/N, respectively). The results indicate that the tantalum doped PZT95/5 ceramics can be used for pulsed power devices.