氮气、氧气烧结气氛对(Na_(0.5)Bi_(0.5))_(0.94)Ba_(0.06)TiO_3陶瓷显微结构和电学性能的影响

Effects of nitrogen and oxygen atmospheres at calcination and sintering processes on microstructure and electrical properties of (Na_(0.5)Bi_(0.5))_(0.94)Ba_(0.06)TiO_3 ceramics

为探索点缺陷对钛酸铋钠基陶瓷显微结构和电学性能的影响,在固相反应法制备(Na_(0.5)Bi_(0.5))_(0.94)Ba_(0.06)TiO_3陶瓷的预烧和烧结过程中分别引入氮气和氧气气氛,研究了不同气氛对陶瓷试样的显微结构、介电、压电和铁电性能的影响。X射线衍射及紫外可见漫反射谱测试结果表明:不同气氛在陶瓷试样中引入的点缺陷浓度存在差异,进而导致陶瓷试样的显微结构和退极化温度显著不同。氮气和氧气气氛中制备的陶瓷的平均晶粒尺寸分别为2.1μm和1.0μm,居里温度分别为248℃和258℃,退极化温度分别为76℃和87℃,剩余极化强度分别为27.2μC/cm^2和27.6μC/cm^2,压电常数分别为122pC/N和128pC/N。

In order to explore the effect of point defects on microstructure and electrical properties of the ceramics, the nitrogen and oxygen atmospheres were used separately during the calcination and sintering processes via a solid-state reaction method. Effects of the calcination and sintering atmospheres on microstructure, dielectric, piezoelectric, and ferroelectric properties of the ce- ramics were studied. The results of X-ray diffraction and UV-vis diffuse reflectance spectra imply that the concentration of point defects is different in the ceramics prepared in the different atmospheres. All the ceramics exhibit pure perovskite structure, while their microstructures are signifi- cantly different. The ceramics show similar dielectric constant-temperature curves with different depolarization temperatures. The ceramics prepared in the nitrogen atmosphere and those prepared in the oxygen atmosphere exhibit the mean grain size of 2.1μm and 1.0 μm, the Curie temperature of 248 ℃ and 258 ℃, the depolarization temperature of 76 ℃ and 87 ℃, the remnant polarization of 27.2 gC/cm2 and 27. 6 ℃/cm^2 , the piezoelectric constant of 122 pC/N and 128 pC/N, respectively.