Crystal Surfaces

Mechanistic and fractographic aspects of stress-corrosion cracking (SCC)

“…For 'clean' low-index crystallographic surfaces, STM and numerous other techniques such as low-energy electron diffraction (LEED) have shown that the lattice spacings up to 4-5 atomic layers beneath surfaces can be different from those in the bulk [42]. Contractions of the normal lattice spacings between the fi rst and second layers of 5% or less for low-index crystallographic surfaces, but up to 30% for high-index surfaces, have been observed.…”

“…Thus, it is not surprising that adsorption of environmental atoms involving charge-transfer generally affects the surface-lattice perturbations. Adsorption can (i) reduce the contractions between the fi rst and second layers, (ii) produce an expansion between the fi rst and second layers, (iii) result in reconstruction of previously unreconstructed clean surfaces, or (iv) change the nature of pre-existing reconstructions [42]. Some adsorbates (including metal atoms) can be incorporated into the topmost layers of substrate atoms, i.e.…”