咪唑类离子液体对E52100钢的腐蚀行为及机理研究

发布时间：2018-11-06 20:38

【摘要】：近几年来,离子液体(Ionic Liquid)作为一种新型润滑材料引起了工业和学术等领域的广泛关注。尤其是烷基咪唑类离子液体在多种润滑材料中表现出较低的摩擦系数,作为高性能的液体润滑剂极有可能在高真空和高温环境下的特殊机械润滑中得到应用。而离子液体对基体材料的腐蚀是直接影响离子液体润滑剂工业化应用的关键问题之一,目前关于该方面的研究非常少,腐蚀行为规律和机理尚不清楚,因此本论文开展咪唑类离子液体对轴承专用钢—E52100钢腐蚀行为和机理的研究,具有重要的研究意义和实际应用价值。本论文选取了四种咪唑类离子液体,即1-丁基-3-甲基咪唑六氟磷酸盐([bmim]PF6)、1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF4)、氯化1-丁基-3-甲基咪唑盐([bmim]Cl)和溴化1-丁基-3-甲基咪唑盐([bmim]Br)作为研究对象,通过电化学、扫描电子显微镜-能谱仪(SEM-EDS)、X射线光电子能谱(XPS)和量子化学计算等多种方法对它们的腐蚀性能及分子结构与腐蚀性能之间的关系进行了研究。电化学实验和表面分析研究结果表明:四种咪唑类离子液体对基体都有不同程度的腐蚀,氧气的存在和温度的升高会加速离子液体对E52100钢的腐蚀。较低温度范围内,样品钢在[bmim]BF4离子液体中具有最大的腐蚀反应速率,在较高的温度范围内,对样品钢具有最大腐蚀速率的是[bmim]Br离子液体。E52100钢在[bmim]PF6和[bmim]BF4离子液体中生成的腐蚀产物具有较强的吸附能力,在[bmim]Cl和[bmim]Br离子液体中基体表面会形成明显的局部腐蚀,形成点蚀坑,坑内的腐蚀产物容易剥落。量子化学计算方法结果表明:[bmim]PF6和[bmim]BF4两种离子液体接受电子与铁原子作用的趋势大于提供电子与铁原子作用的趋势,化合物分子稳定,化学反应活性较低,吸附能力较强;[bmim]Br和[bmim]Cl接受电子与铁原子作用的趋势与提供电子与铁原子作用的趋势相差不大,化合物分子相对活跃,化学反应能力强,吸附能力较弱,其中以[bmim]Br反应能力最强。
[Abstract]:In recent years, ionic liquid (Ionic Liquid), as a new lubricating material, has attracted wide attention in industry and academic fields. Especially, alkyl imidazole ionic liquids show low friction coefficient in many kinds of lubricating materials. As a kind of high performance liquid lubricant, alkyl imidazole ionic liquids are very likely to be used in special mechanical lubrication in high vacuum and high temperature environment. However, the corrosion of matrix materials by ionic liquids is one of the key problems that directly affect the industrial application of ionic liquid lubricants. At present, there are very few researches on this aspect, and the corrosion behavior and mechanism are not clear. Therefore, it is of great significance and practical value to study the corrosion behavior and mechanism of imidazole ionic liquid on bearing special steel E52100 steel in this paper. In this paper, four kinds of imidazole ionic liquids, [bmim] PF6, [bmim] BF4, were selected. 1 Ding Ji 3 methyl imidazole salt ([bmim] Cl) and 1 Ding Ji 3 methyl imidazole bromide ([bmim] Br) were studied by electrochemical, scanning electron microscopy and energy dispersive spectrometer (SEM-EDS). Various methods such as X-ray photoelectron spectroscopy (XPS) and quantum chemical calculation were used to study their corrosion properties and the relationship between their molecular structures and their corrosion properties. The results of electrochemical experiments and surface analysis showed that the four imidazole ionic liquids corroded the matrix to varying degrees, and the presence of oxygen and the increase of temperature accelerated the corrosion of E52100 steel by ionic liquids. In the lower temperature range, the sample steel has the maximum corrosion reaction rate in [bmim] BF4 ionic liquid, and at a higher temperature range, The maximum corrosion rate of the sample steel is [bmim] Br ionic liquid. The corrosion products formed by E52100 steel in [bmim] PF6 and [bmim] BF4 ionic liquids have strong adsorption ability. In [bmim] Cl and [bmim] Br ionic liquids, obvious local corrosion is formed on the substrate surface, and pitting pits are formed. Corrosion products in the pits are easy to exfoliate. The results of quantum chemical calculation show that [bmim] PF6 and [bmim] BF4 ionic liquids are more likely to accept the interaction of electrons with iron atoms than to provide electrons for interaction with iron atoms, and the compounds are stable and have low chemical reaction activity. Strong adsorption capacity; The tendency of [bmim] Br and [bmim] Cl to accept the interaction of electron with iron atom is not different from that of providing electron and iron atom. The molecule of compound is relatively active, the ability of chemical reaction is strong, and the ability of adsorption is weak. Among them, [bmim] Br has the strongest reaction ability.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG178

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