作　　者： ; ; ; ; ;

机构地区： 清华大学材料科学与工程系新型陶瓷与精细工艺国家重点实验室

出　　处： 《稀有金属材料与工程》 2006年第A02期165-168,共4页

摘　　要： 采用传统固相反应法对水热BaTiO3粉体进行La2O3和MgO复合掺杂改性。研究(Ba1-xLax)(Ti1-x/2Mgx/2)O3体系的烧结性能、相组成、微观结构及介电性能。研究结果表明:随着掺量x的增加,烧结温度提高,晶体结构逐渐由四方相转为立方相。当x=0．0025时,以Mg2+固溶取代Ti4+位占优势,晶格常数增加;当x≥0．2时,La3+固溶取代Ba位占优势,晶格常数下降。随着掺量的增加,晶粒尺寸减小。x=0．4时,平均晶粒尺寸约为0．33μm,晶粒大小均匀,材料致密。随着掺量的增加,居里温度下降,居里峰展宽,电阻率提高。高掺量情况下(x≥0．2),随着掺量的增加,介电常数增加,介电常数随温度的变化率降低。BaTiO3-La2O3-MgO体系材料可以作为介电特性较为稳定、小尺寸、大容量的片式陶瓷电容器的介质材料。 The conventional solid-state technique was utilized to modify hydrotherrmally-synthesized-BaTiO3 with La2O3 and MgO. Sintering characteristic, dielectric properties, phases and microstructure of （Ba1-xLax）（Ti1-x/2Mgx/2）O3 ceramics were studied in this paper. With the increase of composition x, the sintering temperature increased and the crystal structure changed from the tetragonal to the cubic. when x=0.0025, the substitution of Ti^4＋ for Mg^2＋ was significant, and the lattice parameter was increased. However, when x≥0.2, the substitution of Ba for La^3＋ was significant, and the lattice parameter decreased. Grains size decreased with the increase of composition. When x=0.4, the average grain size was about 0.33 μm, and the sample with compact and uniform microstructure was obtained. With the increase of composition x, the curie point was moved to room temperature and the εr peak was widened and resistivity increased. Where x ≥0.2, dielectric constant increased and TCC decreased with the increase of composition x.

关 键 词： 取代 微观结构 介电性能

领　　域： [一般工业技术]