High-resolution imaging of the (111) Ag/Ni interface

Abstract

Computer simulations of Ag/Ni interfaces using embedded atom potentials have predicted that the interfacial energy of the (111) Ag/Ni interface is lowest. However, the semi-coherent interface configuration implied by these calculations has not been confirmed by experimental observation. It is well known that in heterophase systems with small misfit, the misfit is accommodated by misfit dislocations at the interface, forming a semi-coherent interface. However, it is not clear whether or not and to what degree misfit localization will occur at the interfaces with as large a misfit as 14% (Ag/Ni interface). The purpose of this investigation was to examine the atomic structure of the (111) Ag/Ni interface by high-resolution electron microscopy (HREM) and to compare the result to calculated images based on relaxed and rigid models.Metal-metal composite thin films of Ni particles in a Ag matrix were produced by epitaxial growth on (110) NaCl substrates using a special technique described in detail elsewhere. HREM observations were performed using H-9000 at a Northwestern University operated at 300 kV. The images were obtained near optimum defocus without objective aperture. All image simulations were carried out using the multislice method with EMS program package.