目的 研究斜撑式超越离合器用 Cr7C3涂层和 GCr15 基体与合金钢 9310 对磨时的摩擦性能和磨损机理。方法 在 GCr15 基体上利用化学气相沉积技术制备 Cr7C3涂层样件。利用带有能谱分析仪的扫描电镜、X 射线衍射仪和纳米压痕仪分析测量涂层的厚度和物相组成以及有无 Cr7C3 涂层时样件的显微硬度。利用球盘接触式 SRV-4 高温摩擦磨损试验机考察 Cr7C3涂层和 GCr15 基体的摩擦磨损性能。采用三维白光干涉形貌仪和扫描电镜系统地分析材料的磨痕情况。结果 Cr7C3涂层厚度约为 4~6 μm，主要包含 Cr7C3和(Cr,Fe)7C3 两种相。涂层的平均显微硬度为 22.709 GPa，约为 GCr15 基体（11.198 GPa）的 2 倍。在试验参数下，Cr7C3 涂层的摩擦系数为 0.18~0.24，GCr15 基体的摩擦系数为 0.15~0.20。当滑动速度为 60 mm/s，法向载荷为 20 N~60 N 时，GCr15 的磨损率约是 Cr7C3涂层的 4~6 倍；当滑动速度为 100 mm/s 时，GCr15 基体的磨损率约是 Cr7C3涂层的 7~11 倍。当滑动速度为 100 mm/s，法向载荷为 60 N 时，GCr15 基体的磨损机理为典型的犁沟磨损。Cr7C3涂层主要为犁沟磨损和一定的疲劳磨损。结论 Cr7C3涂层具有较高的硬度和良好的耐磨性，有助于改善基体的耐磨性能和斜撑式超越离合器的使用性能。

The work aims to study frication property and wear mechanism of Cr7C3 coating or GCr15 substrate being rubbed with 9310 alloy steel for sprag overrunning clutch. Cr7C3 coating sample was prepared on GCr15 substrate by adopting chemical vapor deposition technology. The thickness and phase composition of Cr7C3 coating and microhardness of both samples (with and without Cr7C3 coating) were analyzed by scanning electron microscope (SEM) (with EDS analysis)，X-ray diffractometer (XRD) and nano-indenter. Friction and wear properties of Cr7C3 coating and GCr15 substrate were investigated with ball-on-disk SRV-4 high temperature tribotester. Wear scar conditions of the materials were characterized systematically with 3D white light interferometer surface profiler and SEM. It was calculated that the thickness of Cr7C3 coating was about 4~6 μm. And it was mainly composed of phase Cr7C3 and phase (Cr,Fe)7C3. Average surface microhardness of the Cr7C3 coating was 22.709 GPa, nearly twice that of GCr15 substrate (11.198 GPa). Under experimental parameters, frication coefficient of the Cr7C3 coating ranged between 0.18~0.24 while that of GCr15 substrate ranged between 0.15~0.20. Wear rate of GCr15 was about 4~6 times that of Cr7C3 coating at the sliding speed of 60 mm/s and normal load of 20~60 N, but 7~11 times that of Cr7C3 coating at the sliding speed of 100 mm/s. The wear mechanism of GCr15 substrate was typical furrow wear, and that of Cr7C3 coating was mainly furrow wear and fatigue wear at the sliding speed of 100 mm/s and normal load of 60 N. Cr7C3 coating has high microhardness and excellent wear resistance, which can contribute to better wear resistance of the substrate and higher usability of sprag overrunning clutch.