CrN films deposited by ion source-assisted magnetron sputtering

CrN coatings were deposited on Si（100） and piston rings by ion source assisted 40 kHz magnetron sputtering.Structure and composition of the coatings were characterized by X-ray diffraction,atomic force microscopy,scanning electron microscopy and transmission electron microscopy.Mechanical and tribological properties were assessed by microhardness and pin-on-disc testing.The ion source-assisted system has a deposition rate of 3.88 μm/h,against 2.2 μm/h without ion-source assistance.The CrN coatings prepared with ion source assistance exhibited an increase in microhardness（up to 16.3 GPa） and decrease in friction coefficient（down to 0.48） at the optimized cathode source-to-substrate distance.Under optimized conditions,CrN coatings were deposited on piston rings,with a thickness of 25 μm and hardness of 17.85 GPa.