Surface diffusion of metals: a comparison of intrinsic and mass transfer measurements

A review of selected results of surface self-diffusion and heterogeneous surface diffusion measurements is presented. Experiments utilizing the field ion microscope (FIM), usually confined to a low-temperature regime, are compared to macroscopic experiments carried out at high temperature. Certain intrinsic differences between these two approaches are pointed out during the discussion of results. A more self-consistent picture of microscopic and macroscopic (thermodynamic) surface variables appears to be necessary in order to arrive at a uniform understanding of all experiments. In this context, the role of surface defects, such as steps, kinks, etc., are discussed in detail. In the range of macroscopic variables, the energy of formation of surface defects, ΔH/sup f/, is experimentally still not available, and as such a missing link between FIM and mass transfer measurements. Possible experiments for obtaining ΔH/sup f/ are suggested. 15 fig., 82 references