Microstructure and Performance of High-Velocity Oxygen-Fuel Coupled Physical Vapor Deposition (HVOF-PVD) Duplex Protective Coatings: A Review

The paper summarizes the current development of high-velocity oxygen–fuel coupled physical vapor deposition (HVOF-PVD) duplex coatings as protective candidates. Following a detailed historical overview of HVOF and PVD technologies, the fabrication methods for duplex protective coatings are presented. The duplex coating superimposes the synergistic advantages of coatings deposited by HVOF and PVD, where the traditional weaknesses of each technique are modified to a great certain extent. Subsequently, the relation between structural characteristics of the duplex coatings and their mechanical, tribological, and corrosive behavior is described in detail. It is demonstrated that the duplex coatings show more excellent overall performance than coatings deposited by both HVOF and PVD separately. Finally, we summarize the protective performance and promising potential of HVOF-PVD duplex coating for applications as well as the research prospects of challenges in future.