Accession Number : AD0627837

Title :   AN ATOMIC VIEW OF SURFACE SELF-DIFFUSION: TUNGSTEN ON TUNGSTEN,

Corporate Author : GENERAL ELECTRIC CO SCHENECTADY N Y RESEARCH AND DEVELOPMENT CENTER

Personal Author(s) : Ehrlich,Gert ; Hudda,F. G.

Report Date : OCT 1965

Pagination or Media Count : 25

Abstract : Surface diffusion of tungsten adatoms on several smooth, low index planes of the tungsten lattice has for the first time been followed by direct observation of individual atoms in the ion microscope. Contrary to expectation, the mobility at room temperature is found to increase in the order (211) > (321) approx. = (110) > (310) approx. = (111). Migrating atoms are reflected at the boundaries of the (110), (211), and (321) planes; on the latter two, motion along atomic rows is favored over diffusion across lattice steps. From quantitative determinations of the rate of change of the mean square displacement, diffusion coefficients were obtained. Differences in diffusion on the (211) and (321)--planes of very similar structure--suggest a weakening of interatomic forces at lattice edges. (Author)

Descriptors :   (*TUNGSTEN, DIFFUSION), CRYSTAL LATTICES, ATOMIC PROPERTIES, CRYSTAL STRUCTURE, SURFACE PROPERTIES, MICROSTRUCTURE

Subject Categories : Properties of Metals and Alloys
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE