类钙钛矿新铌酸盐Ba_5NdTi_2Nb_3O_(18)的合成、结构与介电特性  

Synthesis, Structure and Dielectric Properties of a New Pervoskite-related Niobate Ba_5NdTi_2Nb_3O_(18)

作　　者：张辉[1] 方亮[1] 洪学鹍[1] 孟范成[1] 刘韩星[1] 袁润章[1] 

机构地区：[1]武汉理工大学材料复合新技术国家重点实验室,武汉430070

出　　处：《无机化学学报》2003年第10期1150-1152,共3页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.50002007);教育部重大项目(No.0201);国际衍射数据中心(ICDD)Grant-in-Aid基金项目(No.02-05)资助

摘　　要：为满足现代通信技术的小型化、集成化与高可靠性的迫切要求,探索具有高介电常数、低介电损耗与低温度系数的微波介电材料引起了材料科学、化学、物理、电子等领域科学工作者的广泛关注,并已开发出复合钙钛矿结构Ba(Zn1/3Ta2/3)O3、钨青铜结构Ba6-3xLn8+2xTi18O54等实用化的高性能材料[1-5].A New Niobate Ba5NdTi2Nb3O18 was synthesized by high temperature solid state reaction in the BaO-Nd2O3-TiO2 -Nb2O5 system. The chemical compositions, crystal structure, microstructure, density and melting point of the new compound were characterized by EPMA, XRD, DTA and so on. Ba5NdTi2Nb3O18 crystallizes the rhombohedral system with unit cell parameters a = 0.51760 (2) nm, c = 4.2102(2) nut, and space group R(3) over bar m, Z = 3. The structure may be described as five (Nb, Ti) O-6 octahedra corner-sharing along c axis to form perovskite layer connected by Ba atoms. The Ba5NdTi2Nb3O18 ceramic exhibits high dielectric constant of 76, low dielectric loss of 5.4 x 10(-4) and small temperature coefficient of dielectric constant of - 85ppm . K-1 at 10MHz due to its close structure and relative high dielectric polarizabilities of Ba2+, Nd3+, Ti4+ and Nb5+. Ba5NdTi2Nb3O18 might be a suitable candidate of high epsilon(r) microwave dielectric ceramics.

关 键 词：铌酸盐 类钙钛矿结构 介电特性 Ba5NdTi2Nb3O18 合成 介电常数 介电材料 

分 类 号：TM225[一般工业技术—材料科学与工程]