目的 在普通低碳钢表面制备含难熔金属Mo的CoCrFeNiMo高熵合金熔覆层，研究熔覆层的组织结构及性能。方法 将Co、Cr、Fe、Ni、Mo金属单质粉末按等摩尔比进行配制并混合均匀，利用等离子熔覆法在Q235钢表面制备CoCrFeNiMo高熵合金熔覆层，采用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、金相显微镜(OM)、扫描电子显微镜(SEM)、显微硬度计对熔覆层的合金成分、相结构、显微组织和硬度进行研究。结果 在等离子熔覆过程中存在元素烧损现象，熔覆层的实际成分为Co1.17Cr0.92Ni1.06Fe0.92Mo0.92(摩尔分数);熔覆层与基材形成了良好的冶金结合，熔覆层主要由FCC相组成，同时夹杂少量富Mo、Cr的σ相;熔覆层显微组织为树枝晶，枝晶内为固溶多种元素的FCC相，枝晶间是由FCC相和富Mo、Cr的σ相组成的共晶组织。高熵合金物相形成规律较为复杂，其相结构不能仅由热力学参数来预判，仍需要实验结果的验证。由于Mo元素的固溶强化及σ相的沉淀强化，使得熔覆层的硬度明显提高，表面硬度约为485HV。结论 利用等离子熔覆法，在Q235钢表面成功制备了含难熔金属Mo的CoCrFeNiMo高熵合金熔覆层，显著提高了CoCrFeNi高熵合金的硬度。

The research is intended to prepare CoCrFeNiMo high-entropy alloy containing refractory metal Mo on the low carbon steel, and do some researches about the microstructure and mechanical properties of this cladding layer, and then provide theoretical reference and the experimental example for the subsequent research of high melting point high-entropy alloy in surface engineering. Co, Cr, Fe, Ni, Mo metal powders were mixed evenly according to the equal molar ratio. And then the CoCrFeNiMo high-entropy alloy cladding layer was manufactured on Q235 steel by plasma cladding. The alloy components, crystal structure, microstructure and microhardness of this cladding layer were investigated by XRF, XRD, OM, SEM and microhardness tester. The results showed that due to the element burning phenomenon in the process of plasma cladding, the actual composition of the cladding layer was Co1.17Cr0.92Ni1.06Fe0.92Mo0.92. The cladding layer formed a good metallurgical bond with the substrate. The cladding layer was mainly composed of FCC phase with a small amount of σ phase. The microstructure was dendrite structure. Furthermore, the dendrite was FCC phase with a variety of elements, and the interdendrite was eutectic structure composed of FCC phase and σ phase rich in Mo and Cr. In addition, the phase formation law of high-entropy alloy was very complex and its phase structure could not be predicted only by thermodynamic parameters, but still needed to be verified by experimental results. Due to the solid solution strengthening of Mo element and the precipitation strengthening of σ phase, the hardness of the cladding layer was obviously improved, and the hardness of the surface was about 485HV. Therefore, the CoCrFeNiMo high-entropy alloy cladding layer is successfully prepared on Q235 steel by plasma cladding. The hardness of CoCrFeNi high-entropy alloy is improved by adding Mo.