采用自重送粉法 ,在 4 0 Cr钢表面用宽带激光熔覆了 Ni WC复合梯度涂层。 RDX分析表明 ,Ni WC复合梯度涂层熔覆区主要是由γ Ni、M2 3C6、M7C3、Ni3B、WC和 W2 C所构成。涂层组织形貌特征随着由 Ni- 50 %WC、Ni- 2 5% WC、Ni- 10 % WC和 Ni基合金各亚层的渐次过渡而发生明显变化 :在复合梯度涂层熔覆区各亚层交界处因激光重熔作用其显微硬度明显降低 ,致使熔覆区沿层深方向出现了几个软化微区 ;在干滑动摩擦磨损条件下 ,Ni- WC复合梯度涂层具有很高的耐磨性 ,其主要磨损机制为磨粒磨损和 WC颗粒剥落磨损 Adopting the self-weight feeding method, the Ni WC composite gradient coating was coated on the surface of 4 0 Cr steel by broadband laser. RDX analysis shows that the cladding region of Ni WC composite gradient coating is composed of γ Ni, M2 3C6, M7C3, Ni3B, WC and W2C. The morphologies of the coatings changed significantly with the gradual transition of sub-layers of Ni-50% WC, Ni-25% WC, Ni-10% WC and Ni-based alloys. The micro-hardness of the sub-layer due to laser remelting significantly reduced, resulting in the cladding area along the depth direction of the emergence of several softened micro-area; dry sliding friction and wear conditions, Ni-WC composite gradient coating has a very High wear resistance, the main wear mechanism for abrasive wear and WC particles flaking wear