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.