Enhancing the barrier properties of a fluorocarbon plasma-deposited coating by producing an Interface of amorphous oxide layer on 316L stainless steel for stent applications

Abstract

An amorphous nano-thick oxide layer was produced by plasma oxidation on a AISI 316L stainless steel substrate to increase the adhesion and stability of a fluorocarbon plasma-deposited coating for biomedical applications. This oxide layer decreased the corrosion rate >10-fold compared with a previous plasma-etched interface. The high corrosion resistance of the oxide layer as a new interface for fluorocarbon plasma-deposited coatings showed significant adhesion improvement by decreasing blisters formation, which are formed due to substrate corrosion. After aging in an aqueous saline solution, defluorination of the coating was less which evidenced that the fluorocarbon coating was more stable on the new interface compared with the plasma-etched interface. The coating on the new interface decreased the corrosion rate >20-fold in deformed samples compared with uncoated deformed samples. Moreover, the fluorocarbon coatings withstood a 25% plastic deformation and also a two-week aging in an aqueous saline solution. The results revealed remarkable properties of the amorphous oxide layer as a new interface on the adhesion and stability enhancement of the fluorocarbon coating to the SS316L substrate in an aqueous saline solution.