激光熔覆Ni20Cr复合涂层的微观组织和摩擦磨损性能

发布时间：2018-05-12 05:40

本文选题：激光熔覆 + MoS2　；参考：《燕山大学》2015年硕士论文

【摘要】：随着航空航天技术的快速发展,传统的润滑油和润滑脂已经不能满足其对密封系统的要求,如何获得具有一定耐磨性,并且具有自润滑性的零部件表面涂层是当前航空航天领域研究的热点。因此,本文通过在Ni20Cr中添加MoS2和Cr3C2/Mo制备自润滑耐磨涂层具有重要的意义。Ni20Cr因其具有较高的耐磨性、优良的耐蚀性以及高温抗氧化性,被选择作为涂层的主要材料。采用激光熔覆的方法,在低碳钢基体上制备Ni20Cr涂层、Ni20Cr+MoS2自润滑涂层以及Ni20Cr+Cr3C2/Mo耐磨涂层,采用金相显微镜(OM)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)、电子背散射衍射(EBSD)分析了涂层的组织和物相,研究了不同载荷条件下的摩擦磨损性能,并对其磨损机理进行了分析。研究结果表明,激光熔覆后的Ni20Cr涂层的组织为γ相。添加MoS2后的Ni20Cr自润滑涂层组织为γ相和Crx Sy,摩擦系数明显降低。对涂层进行了物相分析,未检测到MoS2的存在,MoS2在高温下发生了分解,Cr元素与S元素形成了自润滑性能良好的CrxSy。因此,Ni20Cr+20%MoS2自润滑涂层的摩擦系数最低,自润滑性能最好。激光熔覆后的Ni20Cr+Cr3C2耐磨涂层组织为γ相和Cr3C2。激光熔覆后的Ni20Cr+Mo耐磨涂层组织为γ相。与Ni20Cr涂层相比,Ni20Cr+Cr3C2/Mo涂层的耐磨性均显著提高。Ni20Cr+Cr3C2涂层中存在硬度较高的Cr3C2,而Ni20Cr+Mo涂层中的Mo元素具有较强的固溶强化作用。比较六组Ni20Cr+Cr3C2/Mo涂层的磨损量可知,相同的实验条件下,Ni20Cr+30%Cr3C2的磨损量最低,耐磨性最好。
[Abstract]:With the rapid development of aerospace technology, the traditional lubricating oil and grease can no longer meet the requirements of the sealing system, how to obtain a certain wear resistance, And the self-lubricating surface coating is a hot spot in the field of aeronautics and astronautics. Therefore, it is important to prepare self-lubricating and wear resistant coatings by adding MoS2 and Cr3C2/Mo into Ni20Cr. Ni20Cr is selected as the main coating material because of its high wear resistance, excellent corrosion resistance and high temperature oxidation resistance. Ni20Cr coating Ni20Cr MoS2 self-lubricating coating and Ni20Cr Cr3C2/Mo wear-resistant coating were prepared on low carbon steel substrate by laser cladding. The microstructure and phase of the coating were analyzed by means of metallographic microscope, scanning electron microscope (SEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD). The friction and wear properties of the coating under different loading conditions were studied and the wear mechanism was analyzed. The results show that the microstructure of laser cladding Ni20Cr coating is 纬-phase. After adding MoS2, the microstructure of Ni20Cr self-lubricating coating is 纬 phase and Crx Sys, and the friction coefficient of Ni20Cr self-lubricating coating decreases obviously. The phase analysis of the coating shows that the presence of MoS2 and MoS _ 2 decompose Cr and S elements into CrxSys with good self-lubricating properties at high temperature. Therefore, Ni20Cr 20%MoS2 self-lubricating coating has the lowest friction coefficient and the best self-lubricating performance. The microstructure of laser cladding Ni20Cr Cr3C2 wear-resistant coating is 纬 phase and Cr _ 3C _ 2. The microstructure of laser cladding Ni20Cr Mo wear resistant coating is 纬-phase. Compared with Ni20Cr coating, the wear resistance of Ni20Cr Cr3C2/Mo coating is significantly improved. There is Cr _ 3C _ 2 with higher hardness in Ni20Cr Cr3C2 coating, while Mo element in Ni20Cr Mo coating has stronger solution strengthening effect. Compared with six groups of Ni20Cr Cr3C2/Mo coatings, the wear rate of Ni20Cr 30%Cr3C2 is the lowest and the wear resistance of Ni20Cr 30%Cr3C2 is the best under the same experimental conditions.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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