目的 提高铜合金的表面硬度，改善其耐磨性能。方法 利用激光表面合金化和激光熔覆工艺在铜合金表面制备出 Ni/Cu-Cr3C2/Co 梯度涂层。采用 X 射线衍射仪、扫描电镜及能谱仪，系统分析了合金化过渡层与熔覆层的物相构成及显微组织，通过硬度测试、摩擦磨损实验，对梯度涂层的显微硬度和耐磨性进行评估。结果 合金化过渡层组织致密且具有单一柱状晶结构，主要由 α-(Cu,Ni)固溶体、Ni3Al 和 NiAl 构成。Cr3C2/Co 复合熔覆层中分布着未熔 Cr3C2颗粒，且以未熔 Cr3C2颗粒为中心，四周有大量呈杆状（或针状）的 M23C6和 M7C3型碳化物，这种碳化物可以有效提高熔覆层的硬度。梯度涂层的显微硬度从基体的 80HV 逐渐增加到熔覆层的 640HV，梯度涂层的摩擦磨损失重仅为铜合金基体的 1/8。铜基体的磨损表面发生大规模破坏并形成大量磨屑，其磨损机制主要是粘着磨损；Cr3C2/Co 喷涂层由于内部结合力较弱，出现了大量的疲劳磨损面，其磨损机制为表面疲劳磨损；而 Ni/Cu-Cr3C2/Co 梯度涂层的磨损表面比较平整，只存在轻微的“犁沟”，其磨损机制为典型的磨粒磨损。结论 梯度涂层由于 Cr3C2、M23C6及 M7C3相的存在，显微硬度和耐磨性能显著提高。同时，涂层的成分与性能均呈一定的梯度变化，改善了铜基体与涂层的相容性。

The work aims to improve surface hardness and wear resistance of copper alloys. A Ni/Cu-Cr3C2/Co gradient coating was prepared successfully on the surface of copper alloy by combining laser alloying and laser cladding technologies. Phase composition and microstructure of the gradient coating were analyzed by X-ray diffractometer, scanning electron micro scope, energy dispersive spectrometer, etc. Microhardness and wear resistance of the gradient coating were evaluated by hardness test and friction-wear test. The alloying transition layer was dense and had a single columnar crystal structure, and phases were mainly composed of α-(Cu,Ni), Ni3Al and NiAl. Undissolved Cr3C2 particles were distributed in the Cr3C2/Co composite cladding layers. A large number of rod-like (or needle-like) M23C6 and M7C3 carbides centered around the undissolved Cr3C2 particles, which could effectively improve hardness of the cladding layer. Microhardness of the gradient coating gradually increased from the 80HV (substrate) to 640HV (cladding layer), and friction-wear loss of the gradient coating was only 1/8 of copper substrate. There was much debris on the worn surface of copper substrate due to massive destruction, and its wear mechanism was mainly adhesive wear. Due to weak internal bonding force, a large number of fatigue wear surfaces appeared on the Cr3C2/Co sprayed coating, and the wear mechanism was surface fatigue wear. However, worn surface of the Ni/Cu-Cr3C2/Co gradient coating was relatively smooth, there were some slight "furrows", and its wear mechanism was typical abrasive wear. Because of the existence of Cr3C2, M23C6 and M7C3 phases, microhardness and wear resistance of the gradient coating are significantly improved. Meanwhile, composition and properties of the coating show a certain gradient change, which improves the compatibility between copper substrate and coating.