目的 提高40Cr齿轮在重载低速下的摩擦学性能。方法 采用离子渗氮和电弧离子蒸发镀（AED）技术在40Cr钢基体上制备了渗氮层和CrN涂层。用X射线衍射仪、扫描电子显微镜、能谱仪和往复式摩擦磨损试验机，研究了经两种表面处理后40Cr钢的物相组成、形貌和摩擦学性能。结果 渗氮样品表面化合物层厚度约10 μm，硬度约为558HV。CrN涂层表面厚度约为4 μm，涂层硬度约为1341HV。在60 N载荷的条件下，渗氮处理后40Cr钢的磨损率为104.17×10-6 mm3/(N?m)，其磨损机理主要为轻微的粘着磨损和磨粒磨损；制备CrN涂层后40Cr钢的磨损率为17.36×10-6 mm3/(N?m)，其磨损机理主要为轻微的磨粒磨损。结论 在20~60 N法向载荷下，制备CrN涂层后，40Cr钢均表现出最优异的耐磨减摩性能。

The work aims to improve tribological properties of 40Cr gear with high load at low speed. Nitrided layer and CrN coating were prepared on 40Cr steel substrate by plasma nitriding and arc-evaporation deposition (AED). Phase composition, morphology and tribological properties of 40Cr steel receiving different surface treatments were investigated with X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and reciprocating friction and wear tester. Thickness and microhardness of the nitrided layer was 10 μm and 558HV, respectively. The thickness and microhardness of the CrN coating was 4 μm and 1341HV, respectively. Wear rate of the 40Cr steel was 104.17×10-6 mm3/(N?m) under the load of 60 N, and the wear mechanism was mainly slight adhesive wear and abrasive wear; the wear rate of the CrN coating on 40Cr steel was 17.36×10-6 mm3/(N?m) under the load of 60 N, and the wear mechanism was mainly slight abrasive wear. The 40Cr steel exhibits the best anti-wear and anti-friction properties under the normal load of 20~60 N after CrN coating is prepared.