目的 获得高质量等离子熔覆铁基涂层的优化成分。方法 以Fe901、Ti、B4C粉为原料，采用反应等离子熔覆法在Q235钢基体上原位合成铁基涂层，研究了反应物(Ti+B4C)/Fe901质量比（15/85、25/75和35/65）对涂层中强化相的形成、界面结合情况、显微组织结构以及硬度的影响。结果 铁基涂层均与基体呈冶金结合。(Ti+B4C)/Fe901质量比较大时，会使界面结合处质量下降。(Ti+B4C)/Fe901比为15/85时，涂层主要由(Fe,Cr)固溶体、TiB2、TiC、Ti8C5、Fe3C和FeB相组成。增大(Ti+B4C)/Fe901比，不会导致新相形成，但可以抑制FeB析出，涂层中的TiC通过多步反应而形成。涂层显微硬度随(Ti+B4C)/Fe901比增大，整体呈上升趋势。(Ti+B4C)/Fe901比不大于25/75时，涂层显微组织较为均匀，显微硬度沿层深方向变化较平稳；进一步增大(Ti+B4C)/Fe901比，涂层显微组织和硬度均呈现梯度分布，涂层上部硬度与下部硬度差值可达630HV0.1。结论 通过调控主要增强相的反应物成分含量，可使等离子熔覆铁基涂层的显微组织和硬度呈现出梯度分布特征或较好的均匀性，从而满足不同的实际应用需求。

The work aims to obtain optimized composition of high quality plasma cladded Fe-based coatings. Fe-based coatings were synthesized in situ on Q235 steel in reactive plasma cladding method with Fe901 alloy, Ti and B4C powders as raw materials. The effects of (Ti+B4C)/Fe901 mass ratio (15/85, 25/75 and 35/65) on formation of reinforcement phases in the coatings, interfacial bonding, microstructure and microhardness of the coatings were investigated. The Fe-based coatings are metallurgically bonded to the substrate. The quality of interface joint deteriorates when (Ti+B4C)/Fe901 mass ratio is high. The coating mainly consists of (Fe, Cr) solid solution, TiB2, TiC, Ti8C5, Fe3C and FeB phases provided with (Ti+B4C)/Fe901 mass ratio of 15/85. Increasing the (Ti+B4C)/Fe901 mass ratio might not result in formation of a new phase, but it can inhibit FeB precipitation. TiC in the coatings takes shape by multi-steps reaction. Microhardness of the coatings generally increases as the (Ti+B4C)/Fe901 ratio increases, and is on the rise on the whole. When (Ti+B4C)/Fe901 ratio is not more than 25/75, microstructure of the coatings is relatively uniform and the microhardness varies steadily along the depth direction. However, the microstructure and microhardness of the coating presents gradient distribution as (Ti+B4C)/Fe901 ratio further increased. Microhardness difference between the upper and lower coating can be up to 630HV0.1. The plasma cladded Fe-based coatings with gradient or uniform microstructure and microhardness can be obtained by adjusting reactant content of the main reinforcement phases, so as to meet different practical application requirements.