La-Nb共掺杂BaTiO_3陶瓷显微结构研究  

Microstructure Characteristics of BaTiO_3 Ceramic Codoped with La-Nb

作　　者：王悦辉[1] 周济[1] 王婷[1] 

机构地区：[1]清华大学新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《稀有金属材料与工程》2007年第6期959-962,共4页Rare Metal Materials and Engineering

基　　金：国家"863"计划(2003AA32G030);国家"973"计划(2002CB61306和2001CB6104);国家基金(50425204);国家自然科学基金(50272032)资助

摘　　要：采用传统固相反应法对水热BaTiO3粉体进行La2O3和Nb2O5双施主复合掺杂,研究(Ba1-xLa2x/3)(Ti1-xNb4x/5)O3陶瓷显微结构特征。结果表明:随着x的增大,晶体结构逐渐由四方相转为立方相。当x≤0.03时,La3+、Nb5+固溶进入BaTiO3晶格形成单一的钙钛矿相;当x=0.05时,出现Ba6Ti17O40富钛第二相;当x≥0.2时,出现Ba-Ti-La-Nb固溶组分的第二相,说明施主掺杂固溶极限x<0.2。当x=0.001时,瓷体具有半导化特征,晶粒尺寸为8～10μm;当x≥0.004时,瓷体开始呈现绝缘性,施主离子表现出明显的抑制晶粒生长作用,随着x增加,晶粒尺寸由10μm(x=0.004)下降至0.5μm(x=0.3)。TEM和EDS分析表明,La3+、Nb5+双施主复合掺杂,La3+提高了Nb5+的扩散固溶能力,相互协同作用使掺杂离子在BaTiO3中分布更均匀。The microstructure characteristics were studied for the （Ba1-xLa2x/3）（Ti1-xNb4x/5）O3 ceramics modified by codoping with La203 and Nb2O5 from hydrotherrmally-synthesized-BaTiO3 using conventional solid-state reaction technique in this paper. With the increase of composition x, the crystal structure changed from tetragonal to cubic. When x≤0.03, a single phase was formed and the secondary titanium-rich phase occurred when x=0.05; but the secondary phase of Ba-Ti-La-Nb solid solution appeared when x≥ 0.2. For x=0.001, the product was semiconducting with a average grains size of about 10 μm; but insulating for x≥0.004. With the increase of x, the grain size decreased from 10 μm （x = 0.004） to 0.5 μm （x = 0.3 ）. The solid solution ability of Nb^5＋ was improved by La^3＋ with a more homogeneous distribution of constituent elements in BaTiO3 by the codoping of La^3＋-Nb^5＋.

关 键 词：BATIO3 La-Nb 显微结构 

分 类 号：TQ174.1[化学工程—陶瓷工业]