Paper TF-TuP13
Tribo-mechanical and Tribo -corrosion Properties of Thin-on-thick Duplex PVD/HVOF Coatings

Tuesday, December 4, 2018, 4:00 pm, Room Naupaka Salon 1-3

The tribo-mechanical, corrosion and, in general, multifunctional performance of metallic substrates can be significantly enhanced by applying a thin-on-thick duplex coating architecture. Specifically, in a very promising system consisting of a High Velocity Oxy-Fuel (HVOF) coating followed by a Physical Vapor Deposition (PVD) coating, the hard thick HVOF layer provides the load carrying capacity of the soft substrate, while the top dense thin PVD film improves the wear and corrosion resistance . In the present work, pure Fe₃Al coatings and composite Fe₃Al:BN coatings (~300 µm), with a hardness between 4.3 and 12.8 GPa, were prepared on SS304 substrates by HVOF. The top thin PVD layer of diamond like carbon (DLC, 1~2 µm) has been prepared by pulsed DC magnetron sputtering. The tribo-mechanical and tribo -corrosion properties of the DLC/SS304, DLC/Fe₃Al/ SS304 and DLC/Fe₃Al:BN / SS304 coating systems were then compared. Application of the DLC layer on top of the HVOF coating allowed one to decrease the friction coefficient from 0.7 to <0.1, and to significantly enhance the wear resistance. Particularly, the DLC/Fe₃Al:BN system exhibits the lowest wear rate of 8×10^-8 mm³/N^-1∙m^-1. The corrosion resistance of the DLC/Fe₃Al system was increased by 3 orders of magnitude. The wear, corrosion, and tribo -corrosion mechanisms are discussed in detail.