Failure Analysis on Mechanical Equipments (Continued) Lecture 7 Electron Optical Analysis Technique

The series of electronic and photon signals produced by a high-speed electron beam incident on a sample surface were introduced. The diffraction mechanisms and imaging mechanisms of transmission electrons, backscattered electrons and secondary electrons, and the principles of qualitative and quantitative analysis of element compositions by characteristic X-ray and Auger electrons were explained. The structures, working principles, working characteristics, sample requirements and sample preparation processes of transmission electron microscope and scanning electron microscope were described in detail. The role of X-ray energy dispersive spectrometer, electron backscatter diffractometer and Auger electron spectrometer in the study of failure mechanism of mechanical equipment components was discussed. The practical application shows that the main application of electron optical analysis technique in the failure analysis of mechanical components was that it could study the essence of component failure from the deep level (up to the atomic level), including the crystal structure, compositions, surface micro-morphology, various characteristics and so on.