硝酸对BiFeO3粉体中杂相的分解反应研究

摘要

以传统固相烧结工艺制备了含有杂相(Bi25FeO40,Bi2Fe4O9)的BiFeO3粉体,并利用X射线衍射(XRD)、背散射电子像(BSE)等技术研究了硝酸对杂相的分解作用.发现硝酸不与BiFeO3以及杂相Bi2Fe4O9产生反应,但由于Bi25FeO40的亚稳性,使得硝酸能够对其进行分解,并生成Bi3+和Fe3+的硝酸盐而溶于水中.此外,本文还讨论了硝酸对杂相Bi25FeO40的分解速率与稀硝酸浓度等的关系,这为制备纯相BiFeO3提供了有益的实验指导.%The BiFeO3 powders are prepared by the conventional solid state reaction,which have some impurity phases (Bi25FeO40,Bi2Fe4O9).The effects of nitrating on the decomposition of the impurity phases in BiFeO3 powders are studied by X-ray diffraction (XRD),backscattered electron (BSE) images and energy-dispersive spectrometry (EDS) quantitative analysis.The impurity phases of Bi2Fe4O9 and BiFeO3 cannot be nitrated by dilute nitric acid.However,Bi25FeO40 phase is metastable,which may be decomposed into nitrate of Bi3+ and Fe3+.The effect of dilute nitric acid concentration on the decomposition rate of Bi25FeO40 phase has also been discussed,which may provide a useful experimental guidance for the preparation of pure-phase BiFeO3.