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Atomic Structures and Defects of As-Grown Nb1+αS2 Platelets on Nb Substrates

Published online by Cambridge University Press:  15 February 2011

Chuxin Zhou  and
L. W. Hobbs
Chuxin Zhou
Affiliation:
Department of Materials Science & Engineering, MIT, Cambridge, MA
L. W. Hobbs
Affiliation:
Department of Materials Science & Engineering, MIT, Cambridge, MA
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Abstract

The interlocking of Nb1+αS2 platelets developed during sulfidation of Nb results in formation of a compact scale. The atomic structure and defects of these platelets were investigated using HREM. The resulting microstructure is very different from conventional microstructure consisting of polygonal grains and polyhedral grain boundaries because of the anisotropy of the crystal structure. The principal phase was identified as 3R-Nb2+αS2 intergrown with 2H-Nb1+αS2, or with some other arrangement of S-Nb-S slabs. The -S6- octahedral sites between two S-Nb-S slabs provide accommodation for extra Nb or foreign atoms and the large non-stoichiometry of Nb1+αS2. Stacking faults along the c axis account for the high density of planar defect structures observed within almost every platelet. Axial lattice fringe images and streaking in the diffraction pattern indicate that the planar defects are normal to the c direction.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 295: Symposium W – Atomic-Scale Imaging of Surfaces and Interfaces , 1992 , 195
Copyright
Copyright © Materials Research Society 1993

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References

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