制备工艺对(Ba0.85Ca0.15)(Ti0.9Zr0.1)O3无铅压电陶瓷结构与性能的影响

采用液相混合与固相烧结相结合的方法制备了(Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃ (BCTZ) 无铅压电陶瓷, 系统研究了烧结保温时间对其相结构、介电、压电和铁电性能的影响以及电学性能随温度的变化。研究结果表明: 制备的陶瓷样品具有单一的四方钙钛矿结构。当烧结温度为1540℃时, 随着保温时间的延长, 样品晶粒尺寸变大, 居里温度(T_c)升高, 压电性能提高, 电致伸缩性能下降。当保温时间为24 h时, BCTZ陶瓷综合性能最为优异: T_c ~90℃, tanδ < 0.05, k_p ~ 0.46, d₃₃ ~ 540 pC/N, P_s ~17 μC/cm²。陶瓷电学性能随温度变化测试结果又表明, BCTZ陶瓷的电学性能具有很强的温度依赖性, 随着温度的升高其电学性能逐渐下降。

Effect of Sintering Process on Microstructure and Properties of Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 Lead-free Ceramics

The lead-free (Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃ (BCTZ) piezoelectric ceramics were prepared by conventional solid state reaction combined with a liquid precursor mixing method. The effects of dwelling time on the structural, dielectric, piezoelectric, and ferroelectric properties as well as the temperature dependence electrical properties of BCTZ ceramics were systematically investigated. The results show that dense BCTZ ceramics are obtained with uniform grain size and tetragonal perovskite structure, without any other impure phase. As sintered at 1540℃ with the dwelling time increasing from 2 h to 24 h, the average grain size of the ceramics increases from 10.5 μm to 38.7 μm, which strongly controls the electric properties of the ceramics. With the grain size increasing, the Curies temperature T_c shifts to a higher temperature, the piezoelectric properties increase while the electric-field-induced strain decreases for the ceramics. The ceramics sintered at 1540℃ for 24 h obtain excellent electrical properties of T_c ~90℃, tanδ < 0.05, k_p~0.46, d₃₃ ~540 pC/N, and P_s ~17 μC/cm². Moreover, electrical measurement at different temperature suggests that BCTZ samples have strong temperature dependence, especially in the temperature range below T_c, where the electric properties of the ceramics decrease with increasing temperature.