为了提高电子背散射衍射技术的空间分辨率,使之能够对纳米尺度的晶粒或超细粉末进行相鉴定和取向分析,本研究通过自主设计的透射模式电子背散射衍射技术的样品台,及调整EBSD探头位置及角度,收集到清晰、完整的透射电子菊池衍射花样。研究了减薄块体样品厚度对透射电子菊池衍射花样的影响,对减薄氧化锆涂层样品进行了t-EBSD面分布分析,其结果的平均角度偏差(MAD)值仅为0.38,成功鉴定出小于30 nm尺度的纳米氧化锆涂层立方相；将超声分散后的纳米TiO2粉体滴在铜网上,采用t-EBSD对纳米颗粒进行点分析,成功鉴定了锐钛矿相和金红石相TiO2,其中纳米锐钛矿TiO2粉体的最小尺寸为20 nm左右,使得扫描电镜中相鉴定的最小分辨率从目前的约100 nm提高到小于30 nm,大大拓展了电子背散射衍射技术在纳米材料研究中的应用范围。
To improve the spatial resolution of electron backscatter diffraction technique, by which phase identification and orientation analysis of the nano scale grain or ultrafine powders can be achieved, a special specimen holder for transmission electron backscatter diffraction techniques (t-EBSD) accompanied by adjusting position and angle of EBSD detector, was newly designed. The new sample holder could fix the STEM samples, enabling clear TEM Kiku-chi diffraction patterns to be successfully collected by EBSD detector. Then the effect of sample thickness on Kikuchi diffraction pattern was investigated. Based on the newly designed holder, the t-EBSD mapping of zirconia coating was acquired with the mean angle deviation (MAD) at only 0.38, successfully identified the cubic phase of less than 30 nm zirconia coating. Put the ultrasonic dispersed TiO2 powder on copper mesh, the point analysis of t-EBSD could identify the anatase and the rutile of TiO2, distinguishing minimum size of anatase phase TiO2less than 20 nm. Therefore, the minimum resolution of phase identification in scanning electron microscopy is improved from about 100 nm to less than 30 nm, demonstrating the electron backscatter diffraction technology a very promising way in nano materials re-search.
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