Influence of carbon content on the crystallographic structure of boron carbide films

Abstract

Boron carbide thin films were synthesised by laser-assisted chemical vapour deposition (LCVD), using a CO 2 laser beam and boron trichloride and methane as precursors. Boron and carbon contents were measured by electron probe microanalysis (EPMA). Microstructural analysis was carried out by Raman microspectroscopy and glancing incidence X-ray diffraction (GIXRD) was used to study the crystallographic structure and to determine the lattice parameters of the polycrystalline films. The rhombohedral-hexagonal boron carbide crystal lattice constants were plotted as a function of the carbon content, and the non-linear observed behaviour is interpreted on the basis of the complex structure of boron carbide.

Decomposition reaction rate of BCl3–CH4–H2 in the gas phase

“…The forward and reverse rate constants of the all elementary reactions (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) (2) and (12) reported in Ref. [3] were also plotted.…”

“…Additionally, by using CO 2 laser beam to assist chemical vapor deposition, Ref. [14] found that the apparent activation energy would decrease to only 27.5 kJ mol −1 . On a tungsten substrate, the activation energy to produce B 4 C is also found at a low value of 56.1 kJ mol −1 [43].…”

“…The fluid oxide phase would then fill the matrix cracks in situ and slow down the in-depth diffusion of oxygen [5]. Boron carbide is often produced via gasphase decomposition of boron trichloride combined with a light hydrocarbon, such as the precursors of BCl 3 -C 6 H 6 [6], BCl 3 -C 2 H 4 -H 2 [7], BCl 3 -C 3 H 6 (propene)-H 2 [8,9] or BCl 3 -CH 4 -H 2 [3,[10][11][12][13][14][15][16], with the chemical vapor deposition (CVD) technique. This process was widely employed because it allows to control easily the thickness and the texture of the materials.…”

Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

“…A c c e p t e d M a n u s c r i p t 4 include chemical vapor deposition (CVD) [6,7], laser-assisted CVD [8,9], magnetron sputtering [10] and pulsed laser deposition (PLD) [11][12][13][14][15][16].…”

Growth of Diamond-Like Carbon and Icosahedral Boron Carbide by Chemical Vapor Deposition System

“…Furthermore, by various boron to carbon stoichiometry, the ratio higher than 2, are known as boron carbides. Boron carbide exists as a stable single phase compound in a large homogeneity range from 8%up to 20% C concentrations [6]. Boron atom suppresses the formation of sp 2 graphitic clusters and increases both the sp 3 bonding and the hydrogen content in the DLC films [7].…”