M. J. Santos | Searcharxiv

arXiv2002

Laser-Assisted Deposition of r-B4C Coatings Using Ethylene as Carbon Precursor

Rhombohedral B4C coatings were synthesised on fused silica substrates by CO2 laser-assisted chemical vapour deposition (LCVD), using a dynamic reactive atmosphere of BCl3, C2H4 and H2. Films with carbon content from 15 to 22 at.% were grown at deposition rates as high as 0.12 micrometers per second. The kinetics of the reactive system used to deposit the B4C films and the influence of growth conditions on the structure and morphology of the deposits were investigated. Keywords: Rhombohedral boron carbide (r-B4C), Laser-CVD, growth kinetics.

cond-mat.mtrl-sci↗

arXiv2002

The Role of Carbon Precursor on Boron Carbide Synthesis by Laser-CVD

This paper focuses on the synthesis of rhombohedral B4C (r-B4C) coatings by CO2 laser-assisted chemical vapour deposition (LCVD), using a dynamic reactive atmosphere of BCl3, H2 and CH4 or C2H4. The influence of the carbon precursor on the deposition kinetics is discussed. The use of ethylene as carbon precursor presents several advantages over the use of methane, which is the conventional carbon precursor in CVD processes. These advantages are mainly related to its high absorption coefficient at the laser wavelength and a higher sticking coefficient, which enables to attain higher deposition rates and film thickness control at lower carbon precursor concentration. Films with carbon content from 15 to 22 at.% were grown at a deposition rate as high as 0.12 micrometers per second. Keywords: Rhombohedral boron carbide (r-B4C), Laser CVD.

cond-mat.mtrl-sci↗