目的 提高高铁制动盘的耐磨性，研究不同磨损条件下的磨损机制。方法 利用激光熔覆技术制备NiCrMo/WC-xNb复合涂层，研究Nb含量对涂层的物相组成、微观组织、力学性能及不同磨损情况下耐磨性能的影响。结果 复合涂层的物相主要包括γ-Ni、σ-CrMo基体相，以及NbC、WC、MoC、Cr23C6等碳化物相。随着Nb含量的增加，涂层内枝晶组织细化，原位生成四边形和花瓣形的NbC强化相。WC、NbC及基体相的硬度(21.69~10.17 GPa)和弹性模量(457.95~293.32 GPa)呈梯度分布，可以有效传递载荷，减少WC在磨损过程中的破损。NbC与WC协同强化，提高了涂层的硬度和耐磨性，添加质量分数9% Nb的涂层的硬度达到67HRC。与未添加Nb的涂层相比，不同载荷下的磨损体积平均降低了30%。通过添加Nb，在30 N载荷下涂层的磨损机制由黏着磨损和磨粒磨损转变为磨粒磨损;在50 N载荷下，涂层的磨损机制为磨粒磨损。磨损频率的增加导致涂层磨损加剧，其耐磨性下降。结论 在复合涂层内原位生成NbC强化相，可有效提高NiCrMo/WC-Nb复合涂层在不同磨损载荷下的耐磨性。

The brake disc is the key to ensure the safe operation of high-speed trains, and it is susceptible to wear and failure in the service process. The preparation of metal-based ceramic composite coatings by surface strengthening techniques such as laser cladding has become one of the ways to improve the wear resistance of material surfaces. In the braking process, the wear load and wear frequency of the brake disc increase in the transitioning from conventional braking to emergency braking, so it is valuable to study the wear mechanism under different wear conditions.