【摘要】 本工作对 xNa_0.5Bi_0.5TiO₃-（1-x）K_0.5Bi_0.5TiO₃系（0.73≤x≤1.0）和 xNa_0.5Bi_0.5TiO₃-（1-x）BaTiO_?系（0.81≤x≤0.99）陶瓷固溶体的压电、铁电性质进行了研究。发现两系统的准同型相界分别位于 x=0.81和x=0.94处;在相界附近的富钠一侧的组分,是开发超声换能材料的较佳组成范含。在这两个系统中,获得了高厚度机电耦合系数（≥0.48）、低平面机电耦合系数（0.165～0.255）、高频率常数(N_?≥2550 Hz·m)、低相对介电系数（290～524）的超声换能材料。该材料还具有无公害、不需密封烧结等工艺优点。更多还原

【Abstract】 The piezoelectric and ferroelectric properties of xNa_0.5Bi_0.5TiO₃-（1-x）K_0.5Bi_0.5TiO₃（0.73≤x≤1.0） and xNa_0.（?）Bi_0.5TiO₃-（1-x）BaTiO₃（0.81≤x≤0.99） ceramic systemshave been studied.It has been found that the morphotropic boundaries between tetra-gonal and rhombohedral phases of the systems are located at the compositions ofx=0.81 and x=0.94 respectively.The Na-rich compositions near the boundaries ofthe systems are the best compositions developing ultrasonic transducers.The new pie-zoelectric ceramic materials with higher thickness coupling factor（≥0.48）,lower pla-nar coupling factor （0.165-0.255）,higher frequency constant （≥2550 Hz·m） andlower dielectric constant （290-524） have been obtained in the systems.It is not ne-cessary for these ceramics to be covered during sintering.In addition there on leadexists in the systems,and no toxic pollutant is liberated in whole process.更多还原