熔融盐法制备BaTiO_3粉体及Rietveld全谱拟合物相表征

通过熔融盐法以BaC2O4、TiO2为前驱体,NaCl为熔盐制备了BaTiO3粉体。SEM分析所得样品为立方状颗粒,粒径为50～300nm。采用Rietveld全谱拟合法对其物相组成进行了分析,并通过变温XRD对BaTiO3相变进行了表征。Rietveld全谱拟合结果表明,该方法制备的BaTiO3粉体在室温下是一种四方、立方混合相,质量分数分别为73.9%、26.1%。精修结果的数值判据分别为:加权剩余方差因子Rwp=5.93%、剩余方差因子Rp=4.78%、拟合优值S(Goodnessoffit)=1.53。变温XRD研究表明所制备的BaTiO3粉体具有四方到立方相的相变。

Synthesis of BaTiO_3 Paticles by Molten Salt Method and Rietveld Refinement Characterization

BaTiO_3 particles are synthesized using BaC_2O_4 and TiO_2 powders as precursors and NaCl as molten flux through a molten salt method.SEM characterization illustrates that the BaTiO_3 particles have a cubic shape and with a size about 50～300nm.The phase composition of the obtained product has been determined using the Rietveld refinement method.XRD at several temperatures is taken to investigate the phase transition of the product.The Rietveld refinement result reveals that the product is made up of a mixture of tetragonal and cubic phases.The mass fraction of tetragonal and cubic phases is 73.9% and 26.1%,respectively.The reliability factors of the refinement are R_(wp)=5.93%,R_p=4.78%,S(goodness of fit)=1.53.Temperature variable XRD reveals that the obtained BaTiO_3 particles have a tetragonal-to-cubic structural phase transition.