目的 提高 Ni-P/nano-WC 复合刷镀层的性能。 方法 利用电刷镀技术将 Ni-P 与 nano-WC 粉末共同沉积在 40Cr 基体表面形成纳米颗粒增强的复合镀层， 再利用电接触技术对 Ni-P/nano-WC 复合镀层进行二次强化。利用光学显微镜、场发射扫描电子显微镜（FESEM）、 X 射线衍射分析（XRD）、 能谱分析（EDS）和显微硬度测量等手段， 分析电接触强化处理对 Ni-P/nano-WC 复合镀层的影响。同时利用滚动摩擦试验分析电接触强化前后复合镀层耐磨性的变化情况。 结果 电接触强化处理后，Ni-P/nano-WC 复合刷镀层的孔隙和裂纹减少， 复合镀层与基体之间的界面在高温和高压的作用下发生焊合。 XRD 分析显示复合镀层的晶粒细化，镀层的晶粒尺寸由 35.35 nm 下降至 26.28 nm。 随着接触电流的加大，复合镀层的硬度也在逐步加大。经过 20 kA 电流的强化，复合镀层平均硬度由 637HV0.1增加到 885HV0.1，镀层硬度分布更加均匀； 4 h 的滚动摩损表明，随着接触电流的加大，试样的质量损失逐步减小，经 20 kA 接触电流强化后的 Ni-P/nano-WC 复合镀层质量损失为 503 mg，比未经电接触强化的 Ni-P/nano-WC 复合镀层低 40%。结论 电接触强化技术能有效改善 Ni-P/nano-WC 复合镀层的微观组织与性能，将镀层界面由机械结合变为冶金结合，同时提高镀层的耐磨性能。

Objective To improve the properties of Ni-P/nano-WC composite coatings. Methods Electro brush plating was used for co-deposition of Ni-P and nano-WC powder on 40Cr surface to form nano-particle reinforced composite coating. The coating was secondly reinforced by electric contact strengthening (ECS). The microstructures and properties of composite coatings were investigated by optical microscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and Vickers hardness analysis. The rolling wear test was used to analyze the wear resistance of strengthened/unstrengthened composite coatings. Results The cracks and pores of composite coatings were reduced after ECS. Furthermore, the composite coating and the substrate were weld under high temperature and pressure environment. The XRD analysis presented that the size of gain of composite coating was refined which was reduced from 35.35 nm to 26.28 nm. With the increase of contacting electric current, the hardness of composite coating was gradually elevated. The average hardness of coatings was increased from 637HV0.1 to 886HV0.1 through the strengthening of electric current of 20 kA. Hence, the coating hardness distribution was more uniform. After 4-hour rolling wear test, the results showed that with the increase of contacting current, the weight losses of samples was gradually reduced. The weight loss of Ni-P/nano-WC composite coatings after 20 kA ECS was 503 mg which was 40% lower than the unstrengthened composite coatings. Conclusion The ECS can effectively improve the microstructure and properties of Ni-P/nano-WC composite coating. The bonding between the composite coating and the 40Cr substrate was changed from mechanical bonding to metallurgical bonding, at the same time, the wear resistance was improved.