中文摘要：

采用等离子束表面冶金技术,通过多道搭接方式在低碳钢基体上制备大面积铁基复合超厚涂层。基于大面积涂层成形的特点,探讨搭接率与涂层厚度等的变化规律,并利用扫描电镜、X射线衍射仪、金相显微镜、显微硬度计及磨损试验分析测试了涂层的相组成、组织及性能。结果表明：表面冶金涂层厚度可达3.0 mm,无裂纹、气孔等缺陷;组织为γ-（Fe,Ni）枝晶、M23C6、CrB及原位合成的TiC陶瓷颗粒,与基体呈良好的冶金结合。由于颗粒强化、细晶强化和弥散强化等多种强化作用,大面积Fe基超厚涂层具有良好的耐磨性能。

英文摘要：

By plasma jet surface metallurgy technology, Fe-based large area coating was produced on the low carbon steel through multiple channel overlap method. Based on the characteristic of the formation mechanism, the variation rules of overlapping rate and coating thickness were investigated. The phase compositions, microstructures and performance of the coatings were analyzed by scanning electron microscope, X-ray diffractometer, optical microscope, microhardness tester and wear tester. The results show that excellent bonding between the coating and carbon steel substrate is ensured by the strong metallurgical interface, and the coating is uniform, continuous and almost defect-free, 3 mm in thickness. The microstructure of the coating is mainly composed of γ-（Fe,Ni） dendrite, M23C6, CrB and TiC ceramic particle which is synthesized in-situ. Because of the particulate reinforced, dispersion strengthening and refinement strengthening, the microhardness and wear resistant of Fe-based coating can be enhanced.