Influence of sintering parameters on structural, dielectric and piezoelectric properties of Ca, La and Sr-doped PZT (PCLSZT) electroceramics

Abstract

The effects of both sintering temperature and soaking time on structural, dielectric and piezoelectric properties of CaCO₃-doped lead lanthanum strontium zirconia titanate (PLSZT) system have been studied. CaCO₃ was mixed with PLSZT according to stoichiometric formula of Pb_0.925Ca_0.005La_0.02Sr_0.05(Zr_0.52Ti_0.48)O₃ or better known as PCLSZT and then milled in a high energy planetary ball mill at 200 rpm for 40 h at room temperature. The milled powder was then pressed into pellets with 13 mm diameter with compaction pressure of 200 MPa and sintered at different sintering temperatures (1100–1300 °C). Based on the obtained optimum sintering temperature, sintering soaking time (2–4 h) was also studied. Single phase of tetragonal perovskite structure was confirmed by XRD analysis when sintered at 1200 °C and also for all soaking times. FESEM micrographs indicated that a lower sintering temperature with shorter sintering time promotes fine grain size. As sintering temperature increased, the grain size was increased from 0.502 µm to 1.208 µm. Although EDX analysis shows the evaporation of PbO increases with higher sintering temperature. Densification of the PCLSZT was reduced with increasing the sintering temperature, but vice versa with soaking time. The results revealed that different sintering conditions have a big impact on PCLSZT electrical properties. An optimum value of dielectric permittivity, piezoelectric coefficient and electromechanical coupling factor of PCLSZT were obtained when sintered at 1200 °C for 3 h.