Abstract: Diamond-like carbon (DLC) films can effectively improve the surface properties of functional components and parts. However, their applications are greatly limited due to the large intrinsic brittleness, high internal stress, limited thickness, poor bonding strength and low load-bearing capacity. Duplex design combining high velocity oxy-fuel (HVOF) coating and DLC film provides the possibility of high-performance and long-life protection for mechanical components in harsh conditions such as high contact stress, high speed and severe wear, hence showing good application prospects. In this study, we prepared the duplex coating consisting of a thick Cr₃C₂-NiCr interlayer and a thin DLC top layer on the 316L stainless steel substate by combining HVOF technology and plasma assisted chemical vapor deposition. The microstructure, the mechanical properties, as well as the tribological behaviors of the coating were investigated under varying loads and compared with the single DLC film. The results showed that the DLC film on stainless steel and Cr₃C₂-NiCr coating had clear multilayer structure, including the Cr interlayer, Cr/WC and WC/DLC transition layer, and DLC top layer, the thicknesses of which were about 260 nm, 280 nm, 760 nm and 3700 nm, respectively. In the duplex coating, the top DLC film showed the obvious collapse in the porous and unconsolidated regions of the Cr₃C₂-NiCr coating, which resulted in the micro-pit characteristics on the surface. Introduction of Cr₃C₂-NiCr coating under the DLC film had little effect on its microstructure and hardness, but significantly improved the bonding strength and load-bearing capacity of DLC film. The Cr₃C₂-NiCr coating as a load-bearing layer can effectively avoid the brittle fracture and spalling failure of DLC film in the process of indentation and scratch tests. In addition, the Cr₃C₂-NiCr coating can realize the smooth transition of material properties from soft substrate to hard film, and can effectively reduce the interfacial stress concentration. The average friction coefficient of single DLC film decreased first and then increased slightly with the increase of applied load. Surface analysis indicated that the carbon-based transfer film was formed on the surface of the counterpart ball at low load, but the plastic deformation, fatigue crack or spalling of the DLC film occurred under high loads, which increased the friction coefficient. Compared to the single DLC film, the friction coefficient of Cr₃C₂-NiCr/DLC duplex coating decreased monotonously with the increase of load, which was conformd to the Hertz elastic contact model. Furthermore, the Cr₃C₂-NiCr/DLC duplex coating had lower wear rate than the single DLC film under different loads, which was mainly attributed to the high load-bearing property of the intermediate ceramic coating. With the increase of load, the wear mechanism of single DLC film changed from abrasive wear to fatigue wear and then to brittle fracture. But for the Cr₃C₂-NiCr/DLC duplex coating, the wear mechanism was mainly abrasive wear, and a small number of debris was "captured and stored" in the micro-pits and "flattened and compacted" to reduce abrasive wear with the increase of load. At the same time, the high load-bearing capacity of duplex coating effectively inhibited plastic deformation and fatigue crack of top DLC film, which was one of the important reasons for its low and relatively stable friction coefficient under high loads. Besides, the excellent tribological properties of the Cr₃C₂-NiCr/DLC duplex coating were also attributed to the stable existence and microstructure evolution of the carbon transfer film on the surface of the counterpart ball.