碳纳米管复合镀层沉积工艺及性能研究

发布时间：2018-03-02 15:31

本文选题：碳纳米管　切入点：复合镀层　出处：《扬州大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳纳米管以其良好的力学性能、电学性能和特殊的中空管状结构广泛运用于工业中,碳纳米管结合工程材料制备耐磨损耐腐蚀的高性能复合材料已成为近年来的热门研究项目。本课题中将碳纳米管作为第二增强相,采用复合电沉积的方式制备镍/碳纳米管复合镀层并对其性能进行分析,主要研究内容如下：(1)研究不同类型表面活性剂对碳纳米管分散性及复合电镀层性能的影响,实验发现阴离子表面活性剂虽不利于碳纳米管在阴极表面的沉积,但显著提高碳纳米管与基质金属之间的结合力,镀层不易产生缺陷,组织致密,硬度和电化学性能良好,在电镀过程中碳纳米管也能较好地保持稳定悬浮状态。研究发现碳纳米管经混酸化处理后被打断,表面带有活性基团,沉降实验中处理后的碳纳米管分散性明显改善。因此,在本论文中通过对碳纳米管进行酸处理并选用阴离子表面活性剂SDS作为碳纳米管的分散剂对其进行分散稳定,得到性能更加优越的复合镀层。(2)以复合镀层的沉积速率和镀层中碳纳米管的百分含量为标准,分别研究电镀液中碳纳米管的浓度、阴极电流密度、沉积的时间、pH、温度、搅拌的速度和分散剂浓度等因素的影响,采用正交实验和极差分析法获得制备复合镀层的最佳工艺条件。SEM图片显示：镀层表面结构致密,碳纳米管在复合镀层中均匀分布。通过能谱图得知复合镀层是由Ni、C、O三种元素组成,实现了碳纳米管和镍的共沉积。(3)镀液中碳纳米管的浓度对复合镀层中表面形貌及组成成分有很大的影响。结果显示随着镀液中碳纳米管浓度的增加,复合电镀层的表面越发粗糙,并且C元素的含量最高可达11.21%。复合镀层硬度测试表明当碳纳米管的浓度为2g/L时,复合镀层的硬度最高。采用三电极系电化学工作站测量复合镀层在3.5%NaCl溶液中的Tafel曲线及交流阻抗谱,结果显示复合电镀层的腐蚀电位大于金属镍层,腐蚀电流小于金属镍层,表明在中性溶液中复合镀层的耐蚀性要比纯镍层好。交流阻抗谱为单容抗弧,复合镀层双电层电容的下降和电荷转移电阻的增加都表明镀层具有更好的耐腐蚀性。
[Abstract]:Carbon nanotubes (CNTs) are widely used in industry because of their good mechanical properties, electrical properties and special hollow tubular structures. Carbon nanotubes (CNTs) bonded with engineering materials have become a hot research project in recent years for the preparation of wear-resistant and corrosion-resistant high performance composites. In this study, carbon nanotubes (CNTs) are regarded as the second reinforcing phase. Nickel / carbon nanotube composite coatings were prepared by composite electrodeposition and their properties were analyzed. The main research contents are as follows: (1) the effects of different surfactants on the dispersion of carbon nanotubes and the properties of composite electroplating coatings were studied. It is found that anionic surfactants are not conducive to the deposition of carbon nanotubes on the cathode surface, but the adhesion between carbon nanotubes and matrix metals is significantly increased, the coating is not easy to produce defects, the microstructure is compact, the hardness and electrochemical properties are good. It was found that the carbon nanotubes were interrupted after mixed acidizing treatment, with active groups on the surface, and the dispersion of carbon nanotubes was improved obviously in the sedimentation experiment. In this paper, the carbon nanotubes were treated with acid and the anionic surfactant SDS was used as dispersant to disperse and stabilize the carbon nanotubes. Based on the deposition rate of the composite coating and the percentage content of carbon nanotubes in the coating, the concentration, cathodic current density, deposition time, pH and temperature of the carbon nanotubes in the electroplating solution were studied, respectively. Under the influence of agitation speed and dispersant concentration, the optimum technological conditions for preparing composite coating were obtained by orthogonal test and range analysis. SEM pictures showed that the surface structure of the coating was compact, The carbon nanotubes are evenly distributed in the composite coating. The results show that the concentration of carbon nanotubes in the plating bath has a great influence on the surface morphology and composition of the composite coating. The results show that the concentration of carbon nanotubes in the plating solution increases with the increase of the concentration of carbon nanotubes in the plating solution. The surface of the composite electroplating layer is rougher, and the content of C element is up to 11.21.The hardness test of the composite coating shows that when the concentration of carbon nanotubes is 2 g / L, The hardness of the composite coating was the highest. The Tafel curve and AC impedance spectrum of the composite coating in 3.5% NaCl solution were measured by the three-electrode electrochemical workstation. The results showed that the corrosion potential of the composite electroplating layer was greater than that of the nickel metal layer, and the corrosion current was lower than that of the nickel metal layer. The results show that the corrosion resistance of the composite coating in neutral solution is better than that of the pure nickel layer, the AC impedance spectrum is single capacitive reactance arc, the decrease of the double layer capacitance and the increase of the charge transfer resistance of the composite coating all show that the coating has better corrosion resistance.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ153;TB383.1

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