相关论文: Phase Diagram of Boron Carbide With Variable Carbo…
Boron Carbide exhibits a broad composition range, implying a degree of intrinsic substitutional disorder. While the observed phase has rhombohedral symmetry (space group R3(bar)m), the enthalpy minimizing structure has lower, monoclinic,…
The assessed phase diagram of the boron-carbon system contains a single non-stoichiometric boron-carbide phase of rhombohedral symmetry with a broad, thermodynamically improbable, low temperature composition range. We combine first…
Configurationally disordered crystalline boron carbide, B$_{4}$C, is studied using first-principles calculations. We investigate both dilute and high concentrations of carbon-boron substitutional defects. For the latter purpose, we suggest…
The assessed binary phase diagram of boron-carbon exhibits a single alloy phase designated "B4C" with rhombohedral symmetry occupying a broad composition range that falls just short of the nominal carbon content of 20%. As this composition…
Due to a large discrepancy between theory and experiment, the electronic character of crystalline boron carbide B$_{13}$C$_{2}$ has been a controversial topic in the field of icosahedral boron-rich solids. We demonstrate that this…
Boron carbide, a lightweight, high temperature material, has various applications as a structural material and as a neutron absorber. The large solubility range of carbon in boron, between $\approx$ 9% and 20%, stems from the…
The atomic structure of icosahedral B$_4$C boron carbide is determined by comparing existing infra-red absorption and Raman diffusion measurements with the predictions of accurate {\it ab initio} lattice-dynamical calculations performed for…
Noting the structural relationships between phases of carbon and boron carbide with phases of boron nitride and boron subnitride, we investigate their mutual solubilities using a combination of first principles total energies supplemented…
Boron is the fifth element in the periodic table and possesses rich chemistry second only to carbon. A striking feature of boron is that B12 icosahedral cages occur as the building blocks in bulk boron and many boron compounds. This is in…
Molybdenum borides were studied theoretically using first-principles calculations, empirical total energy model and global optimization techniques to determine stable crystal structures. Our calculations reveal the structures of known Mo-B…
The icosahedra boron chain and three icosahedra sheets (with {\alpha}, {\delta}4, and {\delta}6 symmetries), constructed by the icosahedra B12, have been obtained as new members of boron family using a highly efficient molecular dynamics…
Boron is an element of fascinating chemical complexity. Controversies have shrouded this element since its discovery was announced in 1808: the new 'element' turned out to be a compound containing less than 60-70 percent of boron, and it…
A family of unusually stable boron cages was identified and examined using first-principles local density functional method. The structure of the fullerenes is similar to that of the B12 icosahedron and consists of six crossing…
Through the use of perturbation theory, in this work we develop a method which allows for a substantial reduction in the size of the plane-wave basis used in density-functional calculations. This method may be used for both pseudopotentials…
The subcarbides B12C3 and B13C2 known for their abrasive properties, can be structurally considered as carbon inserted rhombohedral alpha-B12 and expressed as B12{C-C-C} and B12(C-B-C). Using density functional theory DFT computations, the…
Boron carbide thin films were synthesised by laser-assisted chemical vapour deposition (LCVD), using a CO2 laser beam and boron trichloride and methane as precursors. Boron and carbon contents were measured by electron probe microanalysis…
We present theoretical studies of morphology, stability, and electronic structure of monolayer hexagonal CBN alloys with rich content of h-BN and carbon concentration not exceeding 50 %. Our studies are based on the bond order type of the…
We report a combined experimental and theoretical study of boron carbide under stress/deformation. A special rotating anvil press, the rotating tomography Paris Edinburgh cell (RotoPEC), has been used to apply torsional deformation to boron…
The lithium-carbon binary system possesses a broad range of chemical compounds, which exhibit fascinating chemical bonding characteristics that give rise diverse and technologically important properties. While lithium carbides with various…
Structure and electronic properties of two unusual boron clusters obtained by fusion of borozene rings has been studied by means of first principles calculations, based on the generalized-gradient approximation of the density functional…