铝合金表面铈离子修饰三嗪二硫醇类防护薄膜的制备与性能研究

发布时间：2018-03-16 12:13

本文选题：铝合金　切入点：电沉积　出处：《西北农林科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：均三嗪二硫醇类化合物因具有热力学稳定的三嗪环和高反应活性的巯基而常常被用作金属表面的防护膜,其工艺简单,无毒无害,应用广泛,且具有良好的防腐性能。但是三嗪二硫醇类的薄膜具有分子尺寸方面的缺陷,目前常用的弥补方法包括改变三嗪二硫醇类分子的取代基团、自组装与电化学沉积成膜工艺方法的联合使用以及复合薄膜的制备等方法,至于通过添加活性或者惰性的纳米粒子来修饰均三嗪二硫醇类防护薄膜的研究还没有报道。因此很有必要探索活性或者惰性的纳米粒子对均三嗪二硫醇类防护薄膜的修饰效果。本实验采用的聚合单体为6-N,N-二丁基-1,3,5-三嗪-2,4-硫醇单钠盐(简称DBN),采用AA5052型铝合金为基体,利用电化学技术中的双电位电沉积法聚合成膜。在预处理工艺选择上,通过系统的比较抛光剂打磨处理、电晕处理、混合碱处理及水合肼处理四种预处理方法对电沉积成膜的影响,探索出电沉积均三嗪二硫醇类化合物防护薄膜层的最佳预处理条件。在最佳预处理条件下,探索出最佳的铈离子浓度;在最佳铈离子浓度下,研究了铈离子对三嗪二硫醇薄膜的修饰效果。实验中采取的实验参数为:DBN单体的浓度为5 mmol/L;第一步和第二步的阶跃电位分别为1.6 V和6V,阶跃时间分别为30 s和10 s;电沉积膜后需进行固化处理,温度设置为100℃、时间设置为10 min。实验结论如下:(1)最佳预处理方式为电晕处理。电晕处理后,基体表面不仅不会受到任何损害,而且基体表面电沉积形成的聚合薄膜的疏水性与防蚀能力比其他预处理方式的更好。(2)最佳铈离子浓度为0.5 mM,在该浓度下铈离子修饰的PDB聚合薄膜的疏水性最好,腐蚀电流密度也最小,保护效率最高。(3)FT-IR图谱分析结果表明通过双电位电沉积法能在铝合金表面沉积一层PDB聚合薄膜,且铈离子的存在并不影响PDB聚合薄膜的形成。(4)电化学测试(即开路电位测试,动电位极化曲线测试,电化学阻抗谱分析)结果表明作为活性腐蚀抑制粒子,铈离子修饰PDB聚合薄膜的防腐蚀能力明显增强,其对铝合金基体具有良好的防护性能。(5)初步推测铈离子的自修复作用是由于在阴极区的氧化还原反应产生的OH-离子与铈离子反应生成铈的氧化物或者氢氧化物等沉淀物所致,或是由于铈离子能与PDB聚合薄膜中三嗪环上的π-电子的产生络合作用所致。
[Abstract]:Due to their thermodynamically stable triazine ring and highly reactive thiol, m-triazine dimercaptan compounds are often used as protective film on metal surface. The process is simple, innocuous, and widely used. But the thin films of triazine dimercaptan have some defects in molecular size. The commonly used methods include changing the substituent groups of triazine dimercaptan molecules. The combined use of self-assembly and electrochemical deposition process and the preparation of composite films, There is no report on the modification of triazine-dimercaptan protective films by adding active or inert nanoparticles. Therefore, it is necessary to explore the active or inert nanoparticles for the protection of m-triazine-dimercaptan thin films. The polymerization monomer used in this experiment is 6-N- N- (2-#china_person0#) -1- (3) -triazine-4-mercaptan monosodium salt (DBN), and AA5052 type aluminum alloy is used as the substrate, and the monosodium sodium salt (DBN) is used as the base of the monosodium monosodium (AA5052). The film was polymerized by double potential electrodeposition in electrochemical technology. In the selection of pretreatment process, the polishes and corona treatment were compared systematically. The effects of four pretreatment methods of mixed alkali treatment and hydrazine hydrate treatment on electrodeposition film formation were investigated. Find out the best concentration of cerium ion, at the best concentration of cerium ion, The modification effect of cerium ion on triazine dimercaptan film was studied. The experimental parameters were as follows: concentration of 1: DBN monomer was 5 mmol / L, step potential of the first step and the second step were 1.6 V and 6 V, step time were 30 s and 10%, respectively. S; after electrodeposition, the film needs to be cured, The experimental results show that the best pretreatment method is corona treatment. After corona treatment, the substrate surface will not be damaged. Moreover, the hydrophobicity and corrosion resistance of the polymer films formed by electrodeposition on the substrate were better than those of other pretreatment methods.) the optimum concentration of cerium ion was 0.5 mm, and the hydrophobicity of the PDB polymer films modified by cerium ion was the best at this concentration. The corrosion current density was also the lowest and the protection efficiency was the highest. The results of FT-IR analysis showed that a layer of PDB polymer film could be deposited on the surface of aluminum alloy by double potential electrodeposition. Moreover, the existence of cerium ion has no effect on the formation of PDB polymeric thin films. The results of electrochemical measurements (I. e., open-circuit potential measurement, potentiodynamic polarization curve measurement, electrochemical impedance spectroscopy analysis) indicate that cerium ion is an active corrosion inhibitor particle. The anticorrosion ability of cerium ion modified PDB polymer film was obviously enhanced. It is suggested that the self-repair effect of cerium ion is due to the reaction of OH- ion in cathode region with cerium ion to form cerium oxide or hydroxide. Or because the cerium ion can complexate with 蟺-electron on triazine ring in PDB polymerization film.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ153

【参考文献】