BENEFITS OF HREM FOR THE STUDY OF METAL-CERAMIC INTERFACES

The aim of the present paper is to discuss the advantages of High Reso lution Electron Microscopy (HREM) studies of metal-ceramic interfaces. A review of methods available for the production of interfaces suitab le for observation in a transmission electron microscopy, together wit h a litterature survey of recent relevant studies will be presented fi rst. A selection of examples will serve to illustrate the main points that HREM allows to be tackled : detection of nanometer-size intermedi ate compounds (Ni/MgO, NiO/Pt, MgO/Nb systems), accomodation of steps at the ceramic surface (Fe/Al2O3, Au/MgO, Cu/MnO systems), characteriz ation of misfit dislocations (e.g., Cu/MgO), effect of the image force on the exact position of the dislocation cores, lattice expansion due to elastic mismatch (e.g., Pd/MgO), determination of the chemical nat ure of the terminating atomic planes (e.g., Pd/Al2O3). An introductive discussion of specific problems in the interpretation of HREM images (i.e., numerical image analysis and computer simulations) will be cond ucted and illustrated with the case of incoherent Fe/Al2O3 interfaces.