Metal-ceramic interfaces studied with high-resolution transmission electron microscopy

How the core structure of an interface dislocation network depends on both misfit and bond strength across the interface is investigated. It is shown that, in principle at least, it is possible to assess the bond strength by investigating the atomic structure of the dislocation cores. As examples, t he misfit-dislocation structures at Ag/Mn3O4, Cu/MnO interfaces formed by p arallel close-packed planes of Ag or Cu and O obtained by internal oxidatio n were studied using HRTEM and lattice static calculations. The lattice sta tic calculations are instrumental in indicating the possible dislocation ne twork and their results served as input for HRTEM image simulations which a re then compared with experimental HRTEM images. In addition, the influence of dissolution of a segregating element (Sb) in these systems was also stu died using HRTEM. The influence on Mn3O4 precipitates in Ag is distinct, na mely: (i) the initial precipitates, sharply facetted by solely (111), are c hanged into a globular shape with sometimes also short (220) and (002) face ts, (ii) a partial reduction of Mn3O4 into MnO occurs for a part of the pre cipitates. Further Sb appeared to prevent Oswald ripening of the precipitat es. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. Ali rights reserved.