Abstract:The thick Cr/CrN multilayer coatings with different modulation ratios (1:2, 1:3, 1:5) were deposited on the A100 steel substrate at room temperature by multi-arc ion plating (MAIP). The chamber temperature gradually rose to 160~170 °C during deposition. The modulation structures are designed to optimize the adhesion strength and the mechanical properties. The Cr/CrN multilayer coating with modulation ratio of 1:2 exhibits the highest adhesive strength (Lc=63.8 N), which may be attributed to the highest hardness (H)/elastic modules (E) and H3/E2 values of 0.083 and 0.138, respectively. The thicker the Cr layer, the better the plasticity and tribological properties. The dry friction test shows that the mean coefficient of friction and the specific wear rate of Cr/CrN multilayer coating are decreased by 24% and 94% at most, respectively, compared with those of the single-layer CrN coating. As the Cr layer becomes thick, the wear mechanism is transformed from surface fatigue wear to abrasive wear, which may be attributed to the coordinate changes of hardness and plasticity.