Effect of Nitrogen Flow Rate on Tribological Properties and Corrosion Behavior of CrN-DLC Coating

Abstract

In order to promote the application of diamond-like carbon (DLC) coatings in harsh marine environments, magnetron sputtering technology was used to deposit CrN-DLC coatings on 304 stainless steel. Subsequently, SEM, Raman spectrometer, XPS, EDS, nanoindentation instrument, friction testing machine, three-dimensional profilometer, and electrochemical workstation were utilized to analyze the surface and cross-sectional morphology, microscopic bonding structure, chemical bonding state, composition and element distribution, hardness, tribological properties and corrosion resistance of CrN-DLC films prepared under different nitrogen flow conditions. Results showed that the CrN-DLC coatings had a dense surface structure with no obvious defects, and the deposited coatings were all amorphous in structure. The coatings showed a 55% elastic recovery rate when 2 mL/min N2 was passed through, indicating that the CrN-DLC coatings had good toughness, and the wear rate of the coating prepared under this condition under simulated seawater rubbing against Si3N4 balls was only 8.63×10-10 m3/(N·m). In the electrochemical tests, the anodic polarization curves of all CrN-DLC coatings showed obvious passivation phenomenon. Among them, the corrosion current density of the coating through the 2 mL/min N2 was 2 orders of magnitude lower than that of 304 stainless steel, showing good corrosion resistance. Generally, the structural design and elemental doping of the CrN-DLC coatings could effectively improve the wear and corrosion resistance of 304 stainless steel, which enhanced the application of DLC coatings in the marine environment.

Keywords

• diamond-like composite coating|crn|friction and wear performance|corrosion performance|nitrogen flow rate|magnetron sputtering