Anode layer source plasma-assisted hybrid deposition and characterization of diamond-like carbon coatings deposited on flexible substrates

Diamond-like carbon (DLC) coatings were deposited on nitrile butadiene rubber (NBR) substrates by physical vapor deposition (PVD)-like and chemical vapor deposition (CVD)-like methods. An anode layer source plasma generator was used for surface pre-treatment and deposition of DLC coatings by employing a hybrid method involving magnetron sputtering and plasma-enhanced chemical vapor deposition. The coatings were characterized by scanning electron microscopy, atomic-force microscopy, Raman spectroscopy, nanoindentation and contact-angle goniometer techniques. Due emphasis has been given to studying the tribological characteristics of the coatings under ambient conditions. Oxygen plasma pre-treatment of the NBR substrate, prior to the deposition, resulted in 18% improvement of the average coefficient of friction. Coatings deposited by the PVD-like method showed improved mechanical and tribological properties compared to those deposited by the CVD-like method. Explanations based on coating surface chemistry and microstructure are provided herein to support the relatively superior frictional performance and wear characteristics of the coatings deposited by the PVD-like method.