用俄歇能谱和X射线能谱研究板状碘溴化银微晶中的碘离子的空间分布

本文制备了一系列不同碘含量的板状碘溴化银微晶(微晶大小约为3微米)。运用扫描透射电镜和X射线能谱仪(EDS)对单个微晶进行了分析和研究,半定量地测定了碘离子在板状微晶中的面分布;运用扫描俄歇微区棵针(SAM)和二次电子像、离子溅射剥层技术对微晶进行了表面及其纵深的碘离子的点分析,根据EDS和SAM的结果,可以得到板状碘溴化银微晶中的碘离子的空间分布。实验结果表明在板状缺溴化银微晶中,在其中心部位的碘含量最高;越靠近横向边缘的位置,碘含量越低。且在制备碘溴化银微晶时,如果pAg值较高,将会使在制备早期加入的碘离子通过不断的重结晶向微晶表面扩散,得到的微晶不是夹心结构的碘溴化银微晶。

THE THREE DIMENSIONAL IODIDE ION DISTRIBUTION IN TABULAR Ag(Br,I) MICROCRYSTALS BY SAM AND EDS

A series of tabular silver iodobromide microcrystals with different iodide content (3-18 mol%) was prepared (the average size of the microcrystals is about 3 μm and the aspect ratio is about 6:1). The plane distribution of iodide ions was measured semiquantitatively by means of EDS. Using SAM and ion etching, the surface and spatial analyses of iodide ions were carried out. Combining the results of EDS and SAM, the three dimensional iodide ion distribution was obtained. It is found that the iodide content is higher in the center of the microcry-stal than that in the edge. The nearer to the edge, the lower the iodide content. When the value of pAg is high during precipitation of emulsion, the iodide ions added in the early process are transfered to the surface and are enriched on the surface. The structrue of silver iodobromide microcrystals obtained in this condition are not sandwich type.