DEVELOPMENT OF AN ECONOMICAL ELECTRON BACKSCATTERING DIFFRACTION SYSTEM FOR AN ENVIRONMENTAL SCANNING ELECTRON-MICROSCOPE

A low cost, highly versatile electron backscattering diffraction system has been developed for an ElectroScan E3 Environmental Scanning Electron Microscope (ESEM). A P20 phosphor coated screen is placed in the microscope environment to image electron backscattering diffraction patterns (EBSP's). A CCD TV camera is used to view the patterns through a leaded glass port in the microscope specimen chamber. This system has a spatial resolution approaching 5 mum and yields analyzable patterns at pressures of up to 6 Torr. With minor modifications this system may be adapted to fit any scanning electron microscope. Comparison of analyses of the grain boundary misorientation of a Ni-16Cr-9Fe alloy with this system and by selected area channeling patterns (SACP's), performed in a standard SEM, yielded excellent agreement between the two techniques. Owing to the capability to perform on-line analysis of EBSP's, the EBSP technique required only half the time as the SACP technique. The capabilities of the system are illustrated in a study of the grain boundary character distribution of Ni-16Cr-9Fe following thermomechanical treatment.