中文摘要：

采用固相法制备Na0.25K0.25Bi2.5–xNdxNb2O9（NKBN–xNd3＋,0≤x≤0.4,x为摩尔分数）铋层状无铅压电陶瓷,研究了不同Nd3＋掺杂量对NKBN–x Nd陶瓷显微结构、电学性能的影响及NKBN–0.20Nd3＋陶瓷高温下的电导行为。结果表明：所有样品均为单一的铋层状结构;当Nd3＋的掺杂量x为0.02时,样品的晶粒尺寸减小并趋于均匀,致密度提高;适量的Nd3＋掺杂能降低样品的介电损耗,提高NKBN陶瓷的压电常数d33。NKBN–0.20Nd3＋陶瓷样品的电学性能最佳：压电常数d33=24 pC/N,机械品质因数Qm=2 449,tanδ=0.40%,2Pr=1.11μC/cm2。NKBN–0.20Nd3＋样品的阻抗谱表明：在高温区域陶瓷的晶粒对电传导起主要作用,当温度高于600℃时,样品主要表现为本征电导,NKBN–0.20Nd3＋和NKBN的电导活化能分别为1.85和1.64 eV。

英文摘要：

Na0.25K0.25Bi2.5-xNdxNb209（NKBN-xNd, 0≤x≤0.40） bismuth layered structure lead-free piezoelectric ceramics were prepared by a solid-state reaction method. Effect of Nd3＋ doping amount on the microstructure, electrical properties of NKBN-xNd ceramics was investigated. The high-temperature conductive behavior of NKBN-0.20Nd ceramic was analyzed. The results show that all the samples possess a single bismuth layered structure. When the Nd3＋ doping content x is 0.02, the average grain size decreases, the grain size distribution becomes uniform and the density increases. A appropriate content of Nd^3＋ leads to the decrease of tand and the increase of d33. The NKBN-0.20Nd sample presents the optimal piezoelectric performance, i.e., d33=24 pC/N, Qm=2 449, tand=0.40%, 2Pr=1.11 μC/cm2. According to the impedance spectra of the NKBN-0.20Nd sample, the grain interior makes a major contribution to the electrical conduction process at a high temperature. At 〉 600 ℃, the intrinsic conduction plays a dominant role in the samples. The calculated activation energy of NKBN-0.20Nd and NKBN samples is 1.85 and 1.64 eV, respectively.