Coating tools in advanced manufacturing industries improves tool life and work efficiency. Stamping is widely used in industrial production because of its advantages of high production efficiency, high speed and high material utilization. Therefore, the die industry has become an important foundation for industrial development. Single die material is difficult to meet the higher and higher processing performance requirements, Strengthening the die surface through surface engineering technology has become an important means to improve the die life and efficiency. The mechanical and tribological properties of the die substrate surface can be significantly improved by preparing CrN/Graphit-iC composite coating on the die surface. In order to study the effect of the thickness of Graphit-iC on the mechanical properties and wear resistance of CrN / Graphit-iC coating, Cr / CrN / Graphit-iC coating was prepared on the surface of cold working die steel SDC90 by unbalanced closed field magnetron sputtering technology. The phase structure, mechanical properties and wear resistance of the coating were investigated by XRD, Raman spectroscopy, SEM, nanoindentation, microhardness, scratch test, microindentation and wear test. The experimental results show that the CrN / GLC composite coating is composed of CrN and amorphous phase and/or submicro-crystals of GLC, mainly combined with  structure. With the increase of GLC layer thickness in the composite coating, the hardness increases and the toughness and adhesion decrease; As the thickness of the GLC layer in the composite coating increases, the hardness increases, and the toughness and adhesion decrease; the microhardness (741.56HV0.25N) of the 3.0μm (1.0μm CrN&2.0μm GLC) coating is higher than 0.2μm (1.0μm CrN&0.2μm GLC) 1079.76HV0.25N and 2.0μm (1.0μm CrN&1.0μm GLC) 1468.6HV0.25N; However, the critical load LC is low, 30-40N. When the load is less than the critical load of the coating (wear test load 20N), the 3.0 μ m（1.0 μ m CrN& 2.0 μm GLC) coated samples has the best wear resistance after 8 hours of wear, which is only 31% of the wear volume of untreated samples.

SDC90 steel, Unbalanced Magnetron Sputtering, CrN, GLC, Wear