Review of phase stability in the group IVB and VB transition-metal carbides

Point defects and transport properties in carbides

Review: Transition metal-based nanolamellar phases

Structures ordonnees a longue distance dans les carbures mc dans les fontes

The evolution of vacancy ordering and defect structure in epitaxial YSi2−x thin films on (111)Si have been studied by both conventional and high‐resolution transmission electron microscopy. Epitaxial YSi2−x with an ordered vacancy structure was grown on (111)Si by rapid thermal annealing. In samples annealed at 500 °C for 120 s epitaxial YSi2−x was found to form. After annealing at 600 °C for 15 s, the appearance of additional diffraction spots is attributed to the formation of an ordered vacancy superstructure in the epitaxial YSi2−x thin films. In samples annealed at 600 °C for longer time or higher temperatures, the splitting of extra diffraction spots is correlated to the formation of an out‐of‐step structure. Streaking of the split diffraction spots in the diffraction pattern is attributed to the presence of an out‐of‐step structure with a range of M values. The M was found to settle down to 2 after high‐temperature and/or long time annealing. Planar defects in YSi2−x films were analyzed to be stacki...

Evolution of vacancy ordering and defect structure in epitaxial YSi2−x thin films on (111)Si

Periodic arrangements of anti-phase boundaries (APBs) have been detected by electron diffraction and microscopy in long-range ordered crystals of vanadium carbide near to the composition V 6 C 5, The APBs are non-conservative and are believed to accommodate excess vacancies or carbon atoms in response to deviations in crystal composition from V 6 C 5. The atomic arrangement at non-conservative APBs has been deduced from diffraction contrast analysis of isolated APBs and their observed configurations in crystals containing non-periodic distributions. The observed variation in spacing of the long-periodic structure is consistent with analyses of the average crystal compositions. A mechanism of formation of the long-period structure has been deduced from observations on partially transformed crystals.

J. Billingham

Papers

Long-period order in vanadium carbide