Si-DLC films deposited by a novel method equipped with a co-potential auxiliary cathode for anti-corrosion and anti-wear application

A novel DLC film deposition method was proposed to realize the deposition of DLC film on the surface of complex shaped workpiece. Meanwhile, Si-DLC film was deposited on the surface of M2 high-speed steel (HSS M2) and 304 stainless steel (304SS), and the microstructure, surface roughness, mechanical properties, corrosion resistance and tribological properties of Si-DLC films were characterized in detail. Results show that Si-DLC film at different axial positions of the auxiliary cathode possesses similar microstructure, film thickness and surface roughness, and the as-deposited Si-DLC film shows the low intrinsic stress of < 0.3 GPa. Compared with the 304SS substrate, the Si-DLC film presents more noble corrosion potential, lower corrosion current density and higher polarization resistance, exhibiting higher corrosion resistance. Moreover, the Si-DLC film exhibits higher hardness, elastic factor and plastic factor than HSS M2 substrate and the corresponding adhesive strength is more than 10 N. The Si-DLC film sliding against GCr15 steel ball shows a lower friction coefficient than that of HSS M2 substrate and the wear rate of GCr15 steel ball sliding against the Si-DLC is lower than that of HSS M2 substrate. In addition, this novel method was used to deposit Si-DLC film on gears, drills and bearings without rotating sample racks. As a consequence, this method possesses great potential and can be generalized for the deposition of DLC film on the surface of complex shape workpiece.