溶胶–凝胶法制备NBT-KBT系陶瓷及其电性能

采用sol-gel法制备(1–x)Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3(x=0.12~0.50)系无铅压电陶瓷。XRD分析表明,当x=0.18~0.30时陶瓷具有三方–四方相共存的晶体结构,为该陶瓷的准同型相界(MPB)。在MPB附近存在最佳的电性能:d33为150pC/N,kp为36.7%,ε3T3/ε0为1107,tanδ为1.1×10–2,Qm为168.8,Np为2949.7Hz·m。与常规固相法相比,sol-gel法有利于提高该陶瓷的电性能。分析了该陶瓷材料在1,10和100kHz下的介电温谱,发现该陶瓷是一类弛豫型铁电体材料。

Electric properties of Na_(0.5)Bi_(0.5)TiO_(3-)K_(0.5)Bi_(0.5)TiO_3 system ceramics prepared by sol-gel method

A sol-gel method was applied to prepare the (1–x)Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3(x = 0.12~0.50)system lead-free piezoelectric ceramics. XRD results reveal that the ceramics have trigonal and tetrgonal coexistent phase structures which are near the morphotropic phase boundary (MPB) when x varies from 0.18 to 0.30. The ceramics possess the best piezoelectric and dielectric properties of d33=150 pC/N, kp = 36.7%, ε3T3 /ε0 = 1 107, tanδ = 1.1×10–2, Qm=168.8 and Np = 2 949.7 Hz·m near the MPB. Compared with the conventional solid-state reaction method, the ceramic samples prepared by sol-gel method exhibit better electric properties. At the same time, the relative permittivity (εr) and dielectric loss (tanδ) as a function of temperature under 1, 10 and 100 kHz respectively was analyzed, and it was found that the ceramic is a kind of relaxor ferroelectric material.