文献类型：期刊文献

中文题名：溶胶-凝胶法低温合成Li_(2.06)Nb_(0.18)Ti_(0.76)O_3粉体

英文题名：SYNTHESIS OF Li_(2.06)Nb_(0.18)Ti_(0.76)O_3 POWDER AT LOW TEMPERATURE VIA THE SOL-GEL PROCESS

作者：王霞[1];李蔚[1];施剑林[1,2]

机构：[1]华东理工大学材料科学与工程学院,上海200236;[2]中国科学院上海硅酸盐研究所,上海200050

年份：2010

卷号：38

期号：3

起止页码：414

中文期刊名：硅酸盐学报

外文期刊名：Journal of The Chinese Ceramic Society

收录：CSTPCD;;EI(收录号：20101612868748);Scopus;北大核心:【北大核心2008】；CSCD:【CSCD2011_2012】；

语种：中文

中文关键词：钛酸锂固溶体;溶胶-凝胶法;烧结性能;介电性能;显微结构

外文关键词：lithiumtitanate solid solution; sol-gel method; sintering properties; dielectric properties; microstructure

摘要：以五氧化二铌(Nb2O5)、一水氢氧化锂(LiOH·H2O)和钛酸四丁酯(Ti(C4H9O)4)为原料、柠檬酸为络合剂,通过调节pH值和温度,用溶胶-凝胶法(sol-gel)成功获得透明溶胶。经700℃煅烧,用化学法合成单相钛酸锂(Li2TiO3)固溶体相(Li2.06Nb0.18Ti0.76O3)粉体,其合成温度比普通固相法的低150℃左右。用红外光谱、X射线衍射及扫描电镜(scanning electron microscope,SEM)等表征柠檬酸盐前驱体及煅烧后粉体的性能,详细研究煅烧过程中晶相的转变过程,提出合理的转变机制。结果表明:在煅烧过程中,除Li2TiO3固溶体相外,还出现锐钛矿相TiO2和M相等中间相。随着温度进一步上升,这些中间相消失,最终在700℃得到纯Li2TiO3固溶体相。通过SEM可观察到结晶良好的棒状和块状Li2TiO3固溶体相粉体颗粒。分别研究采用sol-gel和固相法制备样品的烧结性能、显微结及介电性能,结果表明:采用sol-gel得到粉体制备的陶瓷具有特殊的大、小晶粒共存的两种Li2TiO3固溶体相的显微结构,在较低温度(825℃)即达到最大的体积密度3.456g/cm3。与固相法制备样品相比,sol-gel制备样品在同一频率的相对介电常数较小、介电损耗更低。
Lithiumtitanate solid solution（Li2.06Nb0.18Ti0.76O3） powder was successfully synthesized via the sol-gel process.By using Nb2O5,LiOH·H2O and Ti（C4H9O） 4 as the raw materials,and citric acid as the complexing agent,transparent sol was formed by controlling pH values and temperatures.The single-phase of Li2TiO3 solid solution was obtained at 700 ℃using a chemical method,which is 150 ℃lower than the temperatures used in the traditional solid-phase synthesis method.The infrared spectroscopy,X-ray diffraction and scanning electron microscope（SEM） were applied in the characterization of the citrate precursor and the as-obtained powder.The phase transition process was studied in detail and a plausible evolution mechanism of the chemical processed powder in the calcination process was proposed.Results show that during the calcination process,some metastable phases such as the anatase TiO2 phase and M-phase are formed as well as the Li2TiO3 solid solution phase.As the temperature rises,all the metastable phases disappear and pure Li2TiO3 solid solution phase is obtained.The SEM image reveals that the Li2TiO3 solid solution is composed of rod-like and square block particles.The sintering,microstructure and dielectric properties were investigated on the different samples prepared by the sol-gel and solid state methods.The results show that the former presents a special microstructure and reaches the maximum bulk density at low temperatures.The samples as-obtained by the sol-gel method have a lower dielectric constant and dielectric loss at the same frequency as compared to ones prepared by the solid state method.