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热浸镀锌层表面偏钒酸盐转化膜 总被引:1,自引:0,他引:1
在热浸镀锌试样表面获得了一层均匀、完整的偏钒酸盐转化膜.成膜溶液成分及工艺条件为:NaVO3 5 g/L,pH 1.3,温度30 ℃,时间30 min.对比研究了偏钒酸盐转化膜和铬酸盐转化膜的耐蚀性能.结果表明,偏钒酸盐转化膜由Zn、O、V等元素组成,热浸镀锌层经偏钒酸盐转化处理后电化学阻抗和极化电阻增大,腐蚀电流密度... 相似文献
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《电镀与涂饰》2015,(23)
在以氟钛酸为成膜剂的转化液中添加聚丙烯酸(PAA),在热浸镀锌层上制备了氟钛酸–聚丙烯酸复合转化膜(简称H–P转化膜),获得了最佳成膜工艺:H2Ti F6(质量分数60%)5 m L/L,Mn(H2PO4)2·2H2O 15 g/L,PAA 10 m L/L,p H 2.5,处理时间1 min。通过扫描电镜(SEM)研究了复合转化膜成膜过程的表面形貌,采用能谱(EDS)、红外光谱(IR)和X射线光电子能谱(XPS)技术对膜层组成进行了表征。结果表明,PAA参与了成膜反应,所获得的H–P转化膜表面均匀致密,主要由Zn的氧化物、氟化物、磷化物,Ti的氧化物,Mn的氧化物以及聚丙烯酸盐类物质组成,其耐蚀性能比纯氟钛酸转化膜高。 相似文献
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在热浸镀锌层上获得了一层连续、致密的偏钒酸盐–氟锆酸复合转化膜。分析了工艺参数对膜层耐蚀性的影响,确定了成膜的最佳工艺条件为:NaVO3 5.0 g/L,H2ZrF6 6.0 g/L,pH=1.5,成膜时间20 min。采用扫描电镜、能谱仪研究了膜层的微观形貌和元素组成,通过中性盐雾试验及电化学方法测试了膜层的耐蚀性能。与未经处理的热浸镀锌层相比,偏钒酸盐–氟锆酸复合转化膜的盐雾腐蚀面积明显减少,电化学阻抗值显著增大,腐蚀电流密度大幅降低。当成膜时间为20 min时,试样表现出最佳的耐蚀性能,并超过了单纯偏钒酸盐转化膜。 相似文献
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以氟钛酸为成膜剂、磷酸二氢锰为促进剂对热浸镀锌层表面进行钝化处理,获得了氟钛酸转化膜。采用扫描电镜研究了不同处理时间所得转化膜的微观形貌;通过中性盐雾试验、电化学极化和电化学阻抗谱,研究了不同处理时间所得转化膜的耐蚀性。确定了氟钛酸转化膜的制备工艺条件为:H2TiF6(w=60%)5mL/L,Mn(H2PO4)2·2H2O15g/L,pH2.5,处理时间1min。与未经处理的热浸镀锌试样相比,经氟钛酸钝化后的试样在中性盐雾试验中出现白锈的时间明显延迟,在5%NaCl溶液中的腐蚀电流密度明显降低,极化电阻和电化学阻抗显著增大。处理时间为1min时所得转化膜的耐蚀性能最好。 相似文献
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以环境友好型钼酸盐化学转化膜替代传统高污染的铬酸盐钝化膜,是镀锌层钝化工艺技术的发展方向。随着累计处理热浸镀锌钢板面积的增加,新制的钼酸盐钝化处理液会逐渐失去钝化能力。探索出一种能够使失效的处理液恢复钝化性能的氧化型添加剂,研究了添加剂对失效钝化液性能恢复的影响。用电化学极化曲线研究了转化膜的腐蚀行为。结果表明,添加剂的补加使极化曲线阳极分支重新出现钝化特征,即失效钝化液恢复钝化能力。扫描电子显微镜观察表明,补加添加剂后形成的转化膜表面平整、均匀。X-射线能量分析表明,转化膜中含有Mo、P、O和Zn等元素。经24 h盐雾试验表面转化膜具有较好的抗盐雾腐蚀能力。 相似文献
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镀锌层钼酸盐钝化工艺研究 总被引:2,自引:0,他引:2
利用对比试验和正交试验对镀锌层钼酸盐钝化工艺进行了研究,通过中性盐雾试验、湿热试验及盐水浸泡试验,研究了钼酸盐钝化工艺参数对钝化膜耐蚀性的影响.通过X-射线光电子能谱对镀锌层钼酸盐钝化膜层进行了初步分析.结果表明:该处理工艺简单、成本较低,钝化膜主要元素为Zn、Mo、O.镀锌层采用钼酸盐钝化液处理后,耐蚀性明显提高,在3.5%的NaCl溶液中浸泡48 h无白锈生成. 相似文献
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热浸镀锌层表面钛盐转化膜研究 总被引:2,自引:0,他引:2
利用钛盐成膜工艺在热镀锌层表面获得了色泽光亮、耐蚀性能优良的银白色转化膜层。采用扫描电镜、能谱仪、电化学极化和盐水浸泡方法研究了钛盐转化膜层的表面形貌、元素组成和耐蚀性能。分析了钛盐溶液成分及工艺参数对热镀锌层表面转化膜的耐蚀性能影响。确定的最佳工艺条件为:Ti(SO4)21g/L,H2O260mL/L,pH0.5~1.0,处理温度25~30°C,处理时间10min。热镀锌层经此工艺处理后,耐蚀性能明显提高。 相似文献
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A hexafluorozirconic acid-based conversion coating was applied on a galvanized steel substrate and the influence of nickel ion from nickel sulfate solution (in zirconium solution and in a separate solution) on the corrosion resistance behavior and morphology of zirconium conversion coating was investigated. Electrochemical impedance spectroscopy and DC polarization were conducted in 3.5 wt% NaCl solution in order to optimize practical conditions of zirconium conversion coating and NiSO4 solution on the galvanized steel substrate. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were employed to study the morphology and composition of the coated surfaces. Results revealed that the conversion coating obtained from solution containing zirconium and nickel ions (Zr + Ni) did not improve corrosion resistance and uniformity of the coating in comparison with Zr conversion coating in optimized condition. However, a positive effect was obtained from samples coated with separate solutions of zirconium and nickel (Zr–Ni). Improved corrosion resistance and morphology of Zr-based conversion coating were observed in Ni2+ concentration, pH, and immersion time of 10 g/L, 6 and 300 s, respectively. Morphology and surface composition analysis proved that two separate layers of conversion coating containing zirconium, zinc, and nickel oxide/hydroxide compounds were formed in the case samples that were treated by separate solutions. This led to better uniformity and higher thickness of the coating. Finally, adhesion strength of epoxy organic coating on galvanized steel with and without conversion coating was investigated by pull-off measurement. Zr–Ni conversion coating in optimum conditions had a positive effect on adhesion of organic coating in comparison with blank sample and samples pretreated with Zr and Zr + Ni conversion coatings through increased surface roughness and physical interlocking. 相似文献
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Xin-tong Liu Dong-dong Wang Ye-kang Wu Zhong Yang Dalong Li Dejiu Shen 《International Journal of Applied Ceramic Technology》2020,17(3):1017-1025
Ceramic coatings were prepared on 6061 Al alloy in a mixed electrolyte with/without MgO powders at different treatment durations. The results of energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) showed that MgO powder was incorporated into the coatings, and Mg species gradually aggregated into coating inside as prolonging the oxidation time. Scanning electron microscopy (SEM) showed that MgO additive had a certain effect on the microstructures and coating thickness. The corrosion behavior tests evaluated by potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in 3.5 wt% NaCl solution suggested that at the same treatment time, the addition of MgO powders can improve the corrosion resistance of the coating, and the Mg-rich layer can affect the corrosion resistance of the coating. The tests of mechanical properties showed that the addition of MgO powders improved the stability and hardness of the coating. 相似文献
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Conversion coatings on metals enhance paint or lacquer adhesion and promote corrosion resistance. Traditionally, these conversion coatings were based on chromium chemistry. In recent years, formulations based on fluotitanic or fluozirconic acid and polymer have demonstrated performance on a par with chromium-based treatments. The choice of fluoacid and polymer in the treatment has a strong impact on coating performance. The impact of pretreatment composition was demonstrated for aluminum extrusion processes. Electrochemical investigation, including linear polarization and electrochemical impedance spectroscopy, was used to differentiate corrosion resistance among the various treatments. Scanning electron microscopy, grazing angle infrared spectroscopy, and X-ray photoelectron spectroscopy were used to elucidate chemical composition of the treated aluminum surfaces. 相似文献
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Corrosion resistance and infrared emissivity properties of EPDM (EPDM-g-MAH) film on low infrared emissivity PU/Cu coating 总被引:1,自引:0,他引:1
Huijuan Yu Guoyue Xu Xingmei Shen Xiaoxing Yan Chen Hu Yajun Wang 《Electrochimica acta》2010,55(5):1843-2457
In order to improve the corrosion resistance of low infrared emissivity polyurethane (PU)/Cu coating, ethylene-propylene-diene monomer (EPDM) and maleic anhydride grafted EPDM (EPDM-g-MAH) were deposited on PU/Cu coating by spin coating, respectively. The ability of EPDM and EPDM-g-MAH to serve as corrosion protective films for PU/Cu coating was examined by evolved emissivity immersion test and potentiodynamic polarization measurements in 3.5% NaCl solution. And the chemical composition and surface morphology of PU/Cu coating before and after corrosion were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that all of the coated samples present a better corrosion resistance than bare PU/Cu coating due to indissolubility of Cu by aggressive ions, and the effect of EPDM-g-MAH is better than that of EPDM. 相似文献
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在Ce-Mn稀土钝化液中添加Cl-作为促进剂,以6063铝合金为基体制备了Ce-Mn转化膜。分别采用扫描电镜(SEM)和能谱仪(EDS)研究了转化膜的表面形貌及元素组成,并采用硫酸铜点滴腐蚀实验、动电位极化曲线以及电化学阻抗谱(EIS)研究了Ce-Mn转化膜的耐蚀性。结果表明,Ce-Mn转化膜主要由Ce、Mn、O等元素组成,往稀土钝化液中添加Cl-可使膜层更平整、致密,转化膜的平均耐点滴时间从50s提高至100s,在NaCl质量分数为3.5%的腐蚀介质中的腐蚀电流密度明显降低,转化膜极化电阻增大,铝合金的耐蚀性显著提高。 相似文献
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环氧/纳米ZnO复合涂层对镁锂合金耐腐蚀性的影响 总被引:3,自引:0,他引:3
以聚丙烯酰胺凝胶法制备了纳米ZnO,并对其进行改性,得到了环氧/纳米ZnO复合涂层.采用XRD和SEM对环氧/纳米ZnO复合涂层进行了表征.通过极化曲线和交流阻抗研究了裸基、复合涂层以及经锡酸盐转化处理后涂覆环氧/纳米ZnO的复合涂层的耐蚀性能.结果表明:复合涂层呈明显的两相结构,纳米ZnO分布均匀;复合涂层和锡酸盐转化协同,提高了镁锂合金的耐腐蚀性能.涂层中纳米ZnO质量分数不同,对镁锂合金耐蚀性能有不同的影响,纳米ZnO质量分数为2%时,复合涂层对镁锂合金的保护作用最强. 相似文献