First Principles Atomistic Model for Carbon-Doped Boron Suboxide
Final rept. Oct 2013-Jul 2014
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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An atomistic model for the effect of carbon C doping on the structural reorganization of boron suboxide B6O was developed from first principles density functional theory. The results indicate that it is energetically preferable for a single C atom to substitute into an oxygen O site rather than a B site. The lattice parameters and cell volume increase to relieve the residual stress created by the C substitution. Interstitial substitutions are not favorable for single atom substitutions. However, when 2 C atoms replace 2 neighboring O atoms within the B6O unit cell, it becomes energetically favorable to dope an interstitial O, B, or C atom along the C-C chain. If the interstitial dopant is either B or C, a local boron carbide B4C-like structure with either a C-B-C or C-C-C chain is created within the B6O unit cell, which could serve as an intermediate phase in the transformation of B6O into B4C. By promoting the formation of a local B4C-like structure, it may be possible to improve the mechanical stability and elastic properties of B6O.
- Inorganic Chemistry