Ta_2O_5掺杂Bi_2O_3–ZnO–Nb_2O_5陶瓷的晶体结构、结晶化学及介电性能  

Crystal Structure,Crystallochemistry and Dielectric Properties of Ta_2O_5 Doped Bi_2O_3–ZnO–Nb_2O_5 Ceramics

作　　者：彭小松[1] 丁士华[1] 宋天秀[1] 张倩[1] 蒋旭峰[1] 刘旭[1] 

机构地区：[1]西华大学材料科学与工程学院,成都610039

出　　处：《硅酸盐学报》2015年第6期716-722,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(11074203);教育部春晖计划(Z2011077);四川省教育基金(14ZB0126);西华大学研究生创新基金(ycjj2014049;ycjj2014046和ycjj2014050)资助

摘　　要：采用固相反应法制备Bi1.5ZnNb1.5–xTaxO7陶瓷,研究了不同掺杂量Ta2O5对Bi2O3–ZnO–Nb2O5陶瓷相结构、晶体化学特性和介电性能的影响。结果表明:当x≤0.1时,样品均保持单一的立方焦绿石结构(α–BZN)。通过对样品结晶化学计算发现,随着Ta2O5掺杂量的增加,晶格常数a逐渐减小,结晶化学参数键价和AV(O')[A4]增大,AV(O)[A2B2]减小,48f(O)坐标ξ增加。在组成样品晶体结构的多面体中,由6个48f(O)组成的八面体结构(BO6)逐渐变得扭曲,而6个48f(O)和2个8b(O')组成的六面体结构逐渐变得规则,向正立方体结构变化。室温下样品的介电常数和损耗随Ta2O5掺杂量的增加而减小,弛豫度逐渐减小。Bi1.5ZnNb1.5–xTaxO7 ceramics were prepared via conventional solid state reaction.The structure,crystal chemistry and dielectric properties of Bi2O3–Zn O–Nb2O5 ceramics doped with Ta2O5 were investigated.The results reveal that all the ceramic samples are a cubic pyrochlore structure(α–BZN,x≤0.1 mol).The lattice constant and the bond valance sum AV(O')[A4] increase and the AV(O)[A2B2] decreases with increasing the content of Ta2O5.The oxygen coordinate,ξ,of 48f(O) gradually increases.In the polyhedral structures of the samples,the [BO6] octahedrons become more distorted,and the coordinate hexahedrons of A site ions with six 48f(O)s and two 8b(O')s are more regular and approach to cubes when the content of Ta2O5 increases.Also,the dielectric constant,the dielectric loss and the degree of dielectric relaxation all decrease when the content of Ta2O5 increases.

关 键 词：介电性能 立方焦绿石结构 键价和 弛豫度 

分 类 号：TQ174.1[化学工程—陶瓷工业]