热浸镀彩涂板腐蚀失效分析及耐蚀性能对比研究

发布时间：2018-01-16 21:00

本文关键词：热浸镀彩涂板腐蚀失效分析及耐蚀性能对比研究　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：热浸镀彩涂板是一种综合了有机涂层和热浸镀钢板两者优异性能的产品,广泛用于建筑、家电、交通运输等领域。在服役过程中彩涂板会不可避免地出现一些腐蚀失效问题,不但造成严重的经济损失,而且会使各种工程项目存在安全隐患。因此,对彩涂板失效行为的研究,分析其腐蚀失效机理显得尤为重要。热浸镀种类繁多,目前常见的有镀锌和镀铝锌合金两种。本文首先针对合作企业热镀锌彩涂板出现过早腐蚀现象进行了探究,然后对比分析研究了镀铝锌合金与镀锌两种彩涂板的耐蚀性能,以及镀铝锌板耐指纹处理和常规钝化处理的耐蚀性能。具体研究内容如下:(1)通过体视显微镜、金相显微镜、漏涂检测、扫描电镜(SEM)及能谱分析(EDS)、腐蚀失重等实验方法分析了镀锌彩涂板的过早腐蚀现象,发现其原因有涂层漏涂、锌层过薄、基板不平整等。作者认为可能的解决措施有:首先,要尽量选取表面平整的冷轧板。其次,彩涂前要保证镀锌板表面清洁,无任何油脂污染和任何外来颗粒状物质。另外,锌层厚度不宜过薄,要保证彩涂板的耐蚀性能,建议锌重至少要达到70g/m2。(2)通过断面金相观察、SEM观察及能谱分析(EDS)、循环腐蚀实验和电化学阻抗测试(EIS)等方法,全面对比研究了单面镀层厚度同为20μm的镀铝锌150g/m2与镀锌275g/m2两种彩涂板的耐蚀性能。研究结果表明:由于铝锌合金镀层独特的富铝和富锌的两相结构,使得同等厚度的镀铝锌彩涂板比镀锌彩涂板具有更高的耐蚀性能。在长达250个循环(共计2000h)的腐蚀实验中,镀锌彩涂板出现了严重的红色锈迹,而镀铝锌彩涂板并未出现明显腐蚀。在EIS测试中,镀锌彩涂板在浸泡2d后阻抗值就开始急剧下降,而镀铝锌彩涂板在浸泡15d后才开始急剧下降。(3)通过浸泡实验、极化曲线、电化学阻抗谱(EIS)、扫描电镜(SEM)及能谱分析(EDS)等方法对镀铝锌板耐指纹膜和钝化膜的耐蚀性能进行了系统地对比分析。研究结果表明:耐指纹膜试样由于表面致密,比钝化膜试样具有更高的耐蚀性能。在3.5wt.%的NaCl溶液中,耐指纹膜试样的腐蚀速率是钝化膜试样的0.553倍。极化曲线测试中,耐指纹膜试样的阳极反应和阴极反应相对于钝化膜试样均受到不同程度的抑制,其腐蚀电流是钝化膜试样的0.041倍。EIS测试中,耐指纹膜试样的阻抗值比钝化膜试样高出一个数量级。
[Abstract]:Hot dip color coating plate is a kind of product which combines the excellent performance of organic coating and hot dip steel plate. It is widely used in building and home appliances. In the field of transportation and transportation, some corrosion and failure problems will inevitably appear in the course of service, which not only cause serious economic losses, but also make all kinds of engineering projects have safety risks. It is very important to analyze the corrosion failure mechanism of color coating plate. There are many kinds of hot dip plating. At present, there are two kinds of galvanized and aluminized zinc alloy. Firstly, the phenomenon of premature corrosion of hot dip galvanized color coating plate in cooperative enterprises is explored in this paper. Then, the corrosion resistance of Al-Zn alloy and galvanized plate is analyzed and compared. And the corrosion resistance of aluminized zinc plate by fingerprint treatment and conventional passivation treatment. The specific research contents are as follows: 1) through stereoscopic microscope, metallographic microscope, leak coating detection. Scanning electron microscope (SEM), energy dispersive analysis (EDS), corrosion weightlessness and other experimental methods were used to analyze the premature corrosion of the galvanized color coating. It was found that the reasons were the coating leakage and the zinc coating being too thin. The author thinks that the possible solutions are as follows: first, the cold rolled plate with flat surface should be selected as far as possible; secondly, the surface of galvanized sheet should be clean before color coating. In addition, the thickness of zinc layer should not be too thin, to ensure the corrosion resistance of the color coating, it is recommended that zinc weight should be at least 70 g / m ~ (2. 2) through metallographic observation. The methods of SEM observation and energy spectrum analysis, cyclic corrosion test and electrochemical impedance test were used. The corrosion resistance of 150 g / m 2 Al / Zn and 275 g / m 2 galvanized coatings with the same thickness of 20 渭 m was studied. The results show that:. Due to the unique aluminum and zinc rich two-phase structure of Al-Zn alloy coating. The same thickness aluminum-zinc color coating plate has higher corrosion resistance than zinc coating plate. In the corrosion experiment of 250 cycles (2000h), the galvanized color coating plate appears serious red rust. However, there was no obvious corrosion on the aluminum-zinc coating plate. In the EIS test, the impedance value of the galvanized coating plate began to drop sharply after being soaked for 2 days. On the other hand, the aluminum-zinc color coating plate only began to drop sharply after soaking for 15 days.) by immersion experiment, polarization curve, electrochemical impedance spectroscopy (EIS). Scanning Electron Microscopy (SEM) and Energy Spectrum Analysis (EDS). The corrosion resistance of the fingerprint film and the passivation film were compared and analyzed systematically. The results showed that the fingerprint resistant film was compact on the surface. In 3.5 wt.% NaCl solution, the corrosion rate of the fingerprint film specimen is 0.553 times that of the passivated film sample. In the polarization curve test, the corrosion rate of the fingerprint film specimen is 0.553 times higher than that of the passivated film sample. The anodic reaction and cathodic reaction of fingerprint resistant film samples were inhibited to some extent compared with passivation film samples, and the corrosion current was 0.041 times of that of passivated film samples. EIS test showed that the corrosion current of the samples was 0.041 times that of the passivated film samples. The impedance of the fingerprint film specimen is one order of magnitude higher than that of the passivated film sample.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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