中性介质中嘌呤衍生物抑制铜腐蚀的作用机制研究

发布时间：2018-01-16 18:08

本文关键词：中性介质中嘌呤衍生物抑制铜腐蚀的作用机制研究　出处：《山东大学》2017年硕士论文　论文类型：学位论文

更多相关文章：铜缓蚀 电化学测量 SEM XPS 量子化学

【摘要】：铜具有良好的机械、力学、电学及耐蚀性能,在机械、国防、电力、化学等工业领域获得了广泛的应用。但在某些环境下,如含氧的水、氧化性酸以及含Cl-、SO42-等离子的溶液中,铜依然会发生较严重腐蚀。添加缓蚀剂可以有效抑制铜的腐蚀,这种方法不改变金属的物理化学性质,而且经济速效,操作简便,在腐蚀防护领域得到广泛的应用。目前环境问题日益突出,人类环保意识逐渐增强,对缓蚀剂的开发和应用提出了新的要求,环境友好型缓蚀剂成为未来缓蚀剂的发展方向。嘌呤类物质不仅含有丰富N和π键,而且毒性小,可生物降解,易于合成,价格低廉,对其作为缓蚀剂的研究具有重要意义。本论文用传统电化学方法(动电位极化、电化学阻抗)辅以扫描电子显微镜研究了 0.5 M NaCl溶液和0.5 M Na2S04溶液中6-苄氨基嘌呤(6-BA)、6-氯鸟嘌呤(6-CG)、6-巯基嘌呤(6-MP)和腺嘌呤(AD)等四种嘌f$衍生物对铜腐蚀的抑制作用,分析了不同取代基对缓蚀性能的影响并讨论了原因。借助X射线光电子能谱分析了试样表面化学组成,提出了缓蚀剂吸附模型。用量子化学理论确定了缓蚀剂潜在吸附位点,分析了缓蚀性能与量子化学参数的关系。主要工作如下:1.电化学测试采用传统电化学方法(动电位极化、电化学阻抗)研究了 0.5 MNaCl溶液和0.5 MNa2S04溶液中6-BA、6-CG、6-MP和AD对铜的缓蚀作用,结果表明,这四种嘌呤衍生物均有良好的缓蚀性能。动电位极化实验结果显示,6-BA、6-CG、6-MP和AD同时明显降低了阴阳极的腐蚀电流密度,属于混合型缓蚀剂。电化学阻抗实验结果表明,这四种物质增加了表面膜的稳定性,抑制了铜的腐蚀。2.热力学计算进行0.5 MNaCl溶液中AD在铜表面的吸附等温式拟合,结果显示,该条件下AD的吸附符合Langmuir吸附等温式模型,是自发的过程,且物理吸附和化学吸附共同作用。3.表面形貌分析用SEM观察表面形貌并进行对比分析。结果发现,未添加缓蚀剂的试样表面发生了明显的全面腐蚀,产生了许多腐蚀产物,表面变得非常粗糙。而添加缓蚀剂的试样腐蚀轻微,表面有少量的腐蚀产物。说明缓蚀剂能够在铜表面成膜,抑制了铜的腐蚀。4.表面元素检测铜试样表面元素用XPS进行测试。全谱扫描结果显示,浸泡后试样表面有N,证明了缓蚀剂的存在。窄区扫描得到了试样表面的化学组成。此外,根据元素的化学位移,推测出了缓蚀剂的吸附模式,提出了吸附模型:6-CG和AD以平铺的形式吸附在铜表面;6-BA的嘌呤基体和氨基部分也是以平铺的形式吸附,但是苄基部分没有吸附,而是伸入到腐蚀介质中;6-MP通过S和咪唑环内-N=以一定角度吸附在铜表面。5.量子化学计算采用密度泛函理论(DFT),在6-311+G(d)基组下,通过Gaussian 03程序进行所有原子的理论计算,得到了相关的量子化学参数:分子优化结构及其骨架原子的Mulliken电荷分布、最高占据分子轨道能量(EHOMO)、最低未占据分子轨道能量(ELUMO)、能量差(△E)、分子偶极矩(μ)和电子转移数(△N)。确定了潜在的吸附位点,分析了缓蚀性能与量子化学参数的关系。
[Abstract]:Copper has good mechanical, electrical and mechanical, corrosion resistance, mechanical, defense, power, chemical and other industries has been widely used. But in some circumstances, such as oxygen and water, oxidizing acid solution containing Cl-, SO42- plasma, copper still had more serious corrosion to add. The corrosion inhibitor can effectively inhibit the copper, this method does not change the physical and chemical properties of metals, and the economy is quick, simple, widely used in corrosion protection field. At present, environmental problems have become increasingly prominent, the human environmental protection consciousness strengthens gradually, put forward new requirements for the development and application of corrosion inhibitor, environment friendly type inhibitor has become the future development direction of the inhibitor. The purine compounds not only rich in N and pi bond, and has little toxicity, biodegradable, easy synthesis, low price, is of great significance to the study as a corrosion inhibitor on this. The traditional electrochemical methods (potentiodynamic polarization, electrochemical impedance spectroscopy) and scanning electron microscopy studies 6- 6-Benzylaminopurine 0.5 M NaCl solution and 0.5 M Na2S04 solution (6-BA), 6- chloride (6-CG), guanine 6- mercaptopurine (6-MP) and adenine (AD) inhibitory effect of four kinds of purine derivatives on f$copper corrosion, analysis of different substituent effect on corrosion inhibition performance and discuss the reasons. By means of X ray photoelectron spectrum analysis of the chemical composition of sample surface, the corrosion inhibitor corrosion inhibitor adsorption model. The potential adsorption sites determined by quantum chemistry theory, analyzes the relationship between the inhibition efficiency and quantum chemical parameters the main work is as follows: 1. the traditional electrochemical methods (by electrochemical potentiodynamic polarization, electrochemical impedance) of 6-CG 6-BA, 0.5 MNaCl and 0.5 MNa2S04 solutions, 6-MP and AD on the corrosion inhibition of copper used, results show that the four. Good corrosion inhibition performance in derivatives possess potentiodynamic polarization. The experimental results show that 6-BA, 6-CG, 6-MP and AD also significantly decreased the corrosion current density of cathode and anode, belongs to mixed type inhibitor. The electrochemical impedance experiments show that these four substances increase stability of the surface film, inhibiting corrosion thermodynamics.2. the calculation of copper in 0.5 MNaCl solution for AD display results in adsorption isotherm fitting, the copper surface, the adsorption of AD under the Langmuir adsorption isotherm model, is a spontaneous process, and physical adsorption and chemical adsorption with SEM to observe the surface morphology and comparative analysis of the interaction of.3. surface morphology analysis. The results showed that the surface of the sample without obvious comprehensive corrosion inhibitor, produced a lot of corrosion products, surface to become very rough. And the corrosion inhibitor added slightly, a small amount of surface corrosion products At that the inhibitor in the film surface of copper, inhibiting corrosion of.4. surface element copper copper specimen surface element detection was tested using XPS. Full spectrum scanning showed that the surface of the sample after soaking N, proved that the corrosion inhibitor. The chemical composition of the narrow area of the scanning surface. In addition according to the chemical displacement, element, deduced that the adsorption model of corrosion inhibitor, adsorption models were proposed: 6-CG and AD in the form of tile adsorbed on the copper surface; purine substrate and part of 6-BA is in the form of amino acid adsorption tile, but not part of benzyl adsorption, but extends into the corrosive medium; 6-MP by S -N= and imidazole ring at a certain angle adsorbed on the copper surface.5. quantum chemical calculations using density functional theory (DFT), 6-311+G (d) group, through the Gaussian 03 program for all atoms of theoretical calculation of quantum chemistry has been related. Number: Mulliken molecular charge distribution to optimize the structure and skeleton of the atom, the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO), the energy difference (delta E), dipole moment (U) and electron transfer (N). To determine the adsorption potential sites, analysis the relationship between inhibition efficiency and quantum chemical parameters.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.42

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