Investigation of wear and corrosion characteristics of PTFE/TiN composite coating on SS-304 fabricated by two-step sputtering technique

Polytetrafluoroethylene (PTFE) and titanium nitride (TiN) composite coatings have proved to be quite effective anti-corrosion applications owing to the inertness of PTFE and wear resistance of TiN. However, there has been a significant research gap due to the lack of detailed investigation into the mechanisms and characterizations. Inspired by this, our work is focused on investigating the in-depth electrochemical corrosion characteristics of PTFE/TiN composite coating while exploring the contact angles and wear-resistant mechanisms. The PTFE/TiN composite was directly coated on stainless steel (SS-304) substrate by RF magnetron sputtering in two steps. The experimental results indicated that the coating of the PTFE layer modified the characteristic hydrophilic character (& theta;w - 78.2 degrees & PLUSMN; 2 degrees) of the SS-304 surface into an almost superhydrophobic character (& theta;w - 142.6 degrees & PLUSMN; 2 degrees), indorsing the superior protection of SS-304 from aqueous species. Our electrochemical studies revealed that after long-time immersion (6 h) in an alkaline medium, our coating demonstrated a corrosion rate as slow as 0.0026 & mu;m/year with a low surface energy of 4.81 mN/m and high hardness of 16.78 & PLUSMN; 0.36 GPa. Besides, the maximum wear resistance and maximum resistance to fatigue fracture ratios were obtained as H/Er - 0.064 and H3/E 2- 0.068 GPa, respectively. Furthermore, the coating also displayed excellent durability when exposed to air and immersion in chloride solution for a longer time. Lastly, we have included an in-depth discussion of the process steps as well as the mechanism of corrosion initiation.

Automated summary

By investigating the mechanisms and characteristics, the application of polytetrafluoroethylene (PTFE) and titanium nitride (TiN) composite coatings in anti-corrosion has been studied. The experimental results show that the PTFE layer can transform the hydrophilicity of the SS-304 surface into superhydrophobicity, demonstrating excellent corrosion resistance and wear resistance.