Towards new transmission electron microscopy in advanced ceramics

Abstract

This paper reviews several recent improvements in new transmission electron microscopy (TEM) to characterize microstructures in advanced ceramics. Ultra high resolution electron microscopy (UHREM) is a powerful technique to discriminate the species of atoms which are located closer within 0.1 nm, and therefore light elements such as nitrogen and oxygen can be directly observed in the structure image. Low electron dose HREM can be applied to characterize soft ceramics such as zeolite and biomaterials by using slow-scan CCD camera system. High spatial resolution analytical transmission electron microscopy (AEM) can be materialized by designing the pole-piece with small gap and large solid angle for X-ray detector. The chemical composition and chemical bonding state in the very narrow region less than 1 nm can be analyzed by using the present pole-piece with energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) in a field-emission TEM (FE-TEM). Ultra high temperature in-situ observation is performed using special laser heating holder. Sintering behavior of zirconia ultra fine particles, and chemical reaction of zirconia and silica are directly observed by TEM in-situ heating experiment. In addition, in-situ straining observation is possible to observe crack propagation in alumina ceramics by using the crack induced tension (CIT) method which is driven by piezo actuator or micro-step motor. On the basis of the newly developed TEM methods demonstrated here, an concept of "Active-Nano Characterization and Technology" were proposed.