铝合金表面绿色微弧氧化膜层的制备工艺及组织结构

发布时间：2018-02-24 13:41

本文关键词： 铝合金微弧氧化绿色陶瓷膜层钒酸氨　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：铝及其合金具有密度小、导电和导热性能好、延展性好、比强度高、易加工等优点,因此被广泛应用在建筑、汽车、航空航天和船舶等工业领域,但硬度低、耐磨耐蚀性差,表面颜色单一等缺点限制了其更广泛的应用。通过对铝及其合金进行表面处理可以克服这些缺点,在合金表面获得性能优良的彩色陶瓷膜层,因此,铝及其合金的表面着色研究具有重要的理论和实用价值。目前用于铝及其合金的表面着色技术主要包括化学染色法、整体染色法、电解着色法、电泳法、微弧氧化法等。作为一种新兴的着色技术,微弧氧化法因可以在合金表面形成高结合强度、高硬度、耐磨、耐蚀的颜色可调且色泽稳定的陶瓷膜层等优势而具有较高的应用价值。本论文以6063铝合金为基体,在硅酸钠-氢氧化钾(Na2SiO3-KOH)作为主电解液体系中加入甘油和氟化钾(KF),以钒酸氨(NH4VO3)为着色剂,配制着色电解液,制备绿色微弧氧化陶瓷膜层,研究了电解液参数和电参数对微弧氧化膜层组织结构和性能的影响。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和能谱分析仪(EDS)分别对膜层的相组成、微观形貌和元素含量进行表征,分别采用涡流涂层厚度仪、划痕试验仪对微弧氧化陶瓷层的厚度及与基体的结合强度进行检测,利用电化学腐蚀方法对陶瓷层的电化学耐蚀性能进行分析,优化工艺参数,制备出性能良好的绿色微弧氧化膜。试验结果表明,微弧氧化过程中,电解液成分Na2SiO3,正、负电压和正占空比对膜层部分性能的影响规律相似,随着不同影响因素的升高,膜层的颜色逐渐变深；膜层中微孔的孔径、膜层厚度逐渐变大,膜层的耐蚀性能及膜层与基体的结合力先增大后又减小；KF的加入有利于膜层的结合强度和膜层的耐蚀性的提高；随着含量的增加,膜层的粗糙度有所增大,膜层的厚度逐渐增大,基体与膜层间的结合力逐渐增大,膜层的耐蚀性能先增大后减小。通过分析比较得出,当Na2Si03和KF的浓度分别为为6g/L、8g/L和0.5g/L,当正向电压、负向电压和正占空比分别为440V、-40V和30%时,膜层质量最好。另夕,NH4VO3在微弧氧化反应过程中分解生成了V205,膜层中的V2O5使得陶瓷膜层呈现出绿色。
[Abstract]:Aluminum and its alloys have the advantages of low density, good electrical and thermal conductivity, good ductility, high specific strength and easy processing, so they are widely used in industrial fields such as construction, automobile, aerospace and ship, but they have low hardness and poor wear and corrosion resistance. The disadvantages of single surface color limit its wider application. These shortcomings can be overcome by surface treatment of aluminum and its alloys, and color ceramic coatings with excellent properties can be obtained on the surface of the alloy. The research on surface coloring of aluminum and its alloys has important theoretical and practical value. At present, the surface coloring techniques for aluminum and its alloys mainly include chemical staining, integral coloring, electrolytic coloring, electrophoretic staining, As a new technology of coloring, micro-arc oxidation can form high bonding strength, high hardness and wear resistance on the surface of alloy. The ceramic film with adjustable color and stable color has high application value. In this paper, 6063 aluminum alloy is used as the substrate. The green micro-arc oxidation ceramic film was prepared by coloring electrolyte with sodium silicate and potassium hydroxide (Na2SiO3-KOH) as the main electrolyte system, glycerin and potassium fluoride KFU, and vanadate ammonia NH _ 4VO3) as coloring agent. The effects of electrolyte parameters and electrical parameters on the microstructure and properties of the microarc oxide film were studied. The phase composition of the film was observed by X-ray diffractometer, scanning electron microscope (SEM) and energy dispersive analyzer (EDS), respectively. The microstructure and element content were characterized. The thickness of ceramic layer and the bonding strength with substrate were measured by eddy-current coating thickness tester and scratch test instrument, respectively. The electrochemical corrosion resistance of ceramic coating was analyzed by electrochemical corrosion method. The green micro-arc oxide film with good performance was prepared by optimizing the process parameters. The results showed that the electrolyte component Na _ 2SiO _ 3 was positive during the process of micro-arc oxidation. The effect of negative voltage and positive duty ratio on the performance of the film is similar. With the increase of different factors, the color of the film becomes darker, and the pore diameter of the micropore in the film increases, and the thickness of the film becomes larger. The corrosion resistance of the film and the bonding force between the film and the substrate increased first and then decreased, and then the addition of KF was beneficial to the improvement of the bonding strength and corrosion resistance of the film, and the roughness of the film increased with the increase of the content of the film. The thickness of the film increases, the adhesion between the substrate and the film increases, and the corrosion resistance of the film increases first and then decreases. By comparison, it is found that when the concentration of Na2Si03 and KF is 6g / L ~ 8g / L and 0.5g / L, respectively, the forward voltage is obtained. When the negative voltage and positive duty cycle are 440 V -40 V and 30 V, respectively, the film quality is the best. In addition, NH _ 4VO3 decomposes into V _ 205 during the process of micro-arc oxidation, and V _ 2O _ 5 in the film makes the ceramic film green.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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