The Research On Crystal Characteristics Of Typical Materials With Electron Backscattered Diffraction Technics

In this thesis, the analytical system composed of FEI XL-30 scanning electron microscopy and electron backscattered diffraction is used for studying some typical materials.The experiments determining the optimum parameters for obtaining the EBSD pattern were carried out. They are the accelerating voltage 20KV, spot size 6, working distance 15mm, detect distance 60mm and the sample tilt angle 70～71°.EBSD collects the diffraction signal coming from the micron thick top layer, therefore sample preparation is absolutely critical. The methods involved here include mechanical polishing, electro-polishing, chemical etching and ion etching. For metallic materials, which have good electro-conductivity, the electro-polishing or the chemical etching is used in succession to mechanical polishing to remove the deformation layer. For non-conductive materials such as ceramics and the same reason, ion milling or etching was often used; in addition the sample surface has to be coated with thin carbon film.Silicon crystal wafers, iron sheet, aluminum sheet, brass and dual-phase ferrous alloy are tested and analyzed. The experiment is accordant with the known result, which indicates that the processing parameters, operating procedures and also the sample preparation are feasible. We get the microstructure information such as crystal orientation, grain boundary character, grain size distribution and so on. Different phases with the same chemical components can be identified. A pilot study of texture is achieved too.Up to now, EBSD is seldom used to analyze ceramic materials. In this thesis, EBSD sample preparation and analysis for ceramic material is preliminary studied. EBSD analysis on La2Zr2O7 is firstly performed. What we get from the work is compared with the result from XRD, and finally we get the structure information of La₂Zr₂O₇.