Direct atomic-scale imaging of ceramic interfaces

Understanding the atomic structure and chemistry of internal interfaces is often critical to developing interface structure-property relationships. Results are presented from several studies in which Z-contrast scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) have been employed to solve the atomic structures of oxide interfaces, The Z-contrast imaging technique directly reveals the projected cation sublattices constituting the interface, while EELS provides chemical and local electronic structure information. Because Z-contrast imaging and EELS can be performed simultaneously, direct correlations between structure and chemistry can be made at the atomic scale. The utility of Z-contrast imaging and EELS is demonstrated in three examples: a ZrO2 24 degrees [100] symmetric tilt grain boundary, a NiO-cubic ZrO2 eutectic interface and a Ni-cubic ZrO2 metal-ceramic interface. The power and versatility of Z-contrast and EELS for solving interface structures in oxide systems is clearly demonstrated in these three material systems. Published bl Elsevier Science Ltd on behalf of Acta Metallurgica Inc.