Investigation of DLC-Si Film Deposited Inside a 304SS Pipe Using a Novel Hollow Cathode Plasma Immersion Ion Processing Method

摘要

A novel hollow cathode plasma immersion ion processing method is developed and used to deposit silicon containing diamond like carbon (DLC-Si) coatings inside a one foot long 304 stainless steel (304SS) pipe with 1.5 inch diameter and 0.065 inch wall thickness. A multilayer DLC-Si coating structure was deposited using a combination of carbon and silicon precursors starting with silicon-rich adhesion layer. Result shows that the interface between the substrate and adhesion layer contains silicon as well as substrate constituents. Within this interface, isolated crystalline structure embedded within amorphous matrix was present while deposited DLC-Si coating is amorphous. Data show that the layered DLC-Si coating structure not only improves the friction and wear performance of the internal surface of 304SS pipe but also improves the corrosion resistance. The hardness and modulus of the coating was measured at 19GPa and 138GPa, respectively. It is suggested that this new technology enables wide spread use of DLC based coatings to increase component life in applications where the internal surface of pipes are exposed to corrosive and abrasive environments especially in oil and gas industry.