Applied Surface Science, Vol.257, No.7, 2694-2699, 2011
Influence of standoff distance on the structure and properties of carbon coatings deposited by atmospheric plasma jet
Carbon coatings were deposited by atmospheric plasma jet. Influence of the distance between the exit of the plasma gun and a substrate (consequently temperature of the substrate) on properties of the coatings was investigated. The coatings deposited near to the exit of the plasma gun are porous with columnar structure, moderate hardness (similar to 10 GPa), and the lowest hydrogen (similar to 7 at.%) concentration. The coatings deposited at the larger standoff distance (>5mm) have higher hydrogen (<= 25 at.%) content and graphite-like structure. Most of the hydrogen in all coatings is bonded to the sp(3) carbon (70-60 at.%) and predominantly forms methylene compounds. Decrease of standoff distance yields lower concentration of sp(3) CH3 compounds and relative increase of amount of hydrogenated sp(2) rings. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Plasma jet deposition;Acetylene;Amorphous hydrogenated carbon;Raman spectroscopy;IR spectroscopy;Hydrogen