采用传统固相法制备了(1-4x)NBT-3xKBT-xBT(x=0.020-0.035)体系压电陶瓷。通过XRD分析,发现该体系陶瓷都能形成单一的钙钛矿型固溶体,并在0.025≤x≤0.032范围内具有三方和四方共存结构,为该体系的准同型相界。当X=0.028时,d33=162pC/N,Qm=203.29,kp=0.234。同时分析了该体系陶瓷材料在1,10,100kHz下介电常数一温度曲线和介电损耗.温度曲线,发现该体系陶瓷样品的介电温谱都存在两个介电反常峰,且介电常数和介电损耗与频率存在很强的依赖性,表明该体系材料具有弛豫型铁电体性质。
(1-4x)NBT-3xKBT-xBT(x=0.020-0.035) system piezoelectric ceramics were prepared by the conventional solid reaction method. XRD results show that the crystalline structure of the investigated materials were perovskite. The morphotropic phase boundaries(MPB) of the system between rhombohedral and tetragonal locates in the range of x=0.025-0.032, which exhibit the best piezoelectric properties. The piezoelectric constant d33 reached to 162 pC/N and planar electromechanical coupling factor kp enhanced to be 0.234 at x=0.028. It is also found that the ceramic samples are relaxor ferroelectricity from the patterns of dielectric constant as a function of temperature. Two dielectric constant abnormal peaks exists in the dielectric constant vs temperature.