目的 提高材料的表面性能和开拓非晶涂层的应用。方法 将Fe-Cr-Si-P非晶态合金粉末预涂覆于304L不锈钢基材表面，采用宽带激光熔覆技术制备非晶涂层。通过光学显微镜和扫描电镜分析涂层的微观组织结构和界面组织特征。采用FLUENT软件建立宽带激光熔覆的流场模型，并模拟激光熔池内的流场分布。结果 涂层组织具有明显的分层结构，涂层界面区为平面晶和外延树枝晶，涂层中部区域为大面积非晶区，涂层表面为等轴树枝晶，且界面外延生长层的高度随激光扫描速度的增大而减小。激光熔池的流动为对流机制，熔体流动速度在熔池中部出现了低谷，最大速度出现在熔池表面，在熔池下部流体也会出现一个速度峰值。峰值距熔池底端的距离随着扫描速度的增加而减小。结论 宽带激光熔覆的Fe-Cr-Si-P涂层由非晶和树枝晶结晶相组成，涂层组织为分层结构。熔池底部峰值距熔池底端的距离随着扫描速度的增加而减小，且与外延生长层厚度的实测距离基本吻合。建立了激光工艺参数与外延生长层厚度的关系模型，为宽带激光熔覆大面积非晶涂层的可控制备提供了理论依据。

The work aims to improve surface properties of materials and exploit application of amorphous coating. 304L stainless substrate surface was pre-coated with Fe-Cr-Si-P amorphous alloy powder, and then amorphous coating was prepared by broad-band laser cladding technology. Microstructure and interface characteristics of the coating were analyzed with optical microscope (OM) and scanning electron microscopy (SEM). Flow field model of broad-band laser cladding was established using FLUENT software, and flow field distribution in laser molten pool was simulated. The coating had a typical layered structure. There were planar crystalline and dendrites in the interface zone, large area amorphous zones in the middle and fine equiaxial dendrites on the surface of the coating. Thickness of epitaxial growth dendrites decreased with the increase of laser scanning speed. Flow in the molten pool was mainly convective mechanism. Melt flow velocity was the minimum in the middle of the molten pool, and the maximum on the surface, and reached the peak on the bottom. Distance between the peak value positions and the bottom of molten pool decreased with the increase of scanning speed. The broad-band laser cladded Fe-Cr-Si-P coating is composted of amorphous phase and dendrite crystalline phases, and the coating has a layered structure. The distance between peak value positions in lower part and the bottom of molten pool is decreases with the increase of scanning speed, which approximately coincides with measured distance of the epitaxial growth layer thickness. A model is built for relationship between laser process parameters and thickness of epitaxial growth layer, which provides theoretical basis for controllable preparation of large area amorphous coating by broad-band laser cladding technology.