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In order to reduce corrosion rates, zinc plated parts are usually chromated. Recently Chromates have caused increasingly environmental concern, for both allergic effects among workers touching chromated parts and toxic effects on fish, plants and bacteria.A molybdate based alternative has been developed to replace Chromates in several passivation applications. Depending on the environment in which the passivated parts are to be exposed, the protection that this alternative treatment provides range from less efficient to more efficient as compared to Chromate.These aspects as well as issues such as; cost, stability, layer composition and test results from several different corrosion tests are discussed. 相似文献
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Zheludkova E. A. Abrashov A. A. Grigoryan N. S. Asnis N. A. Vagramyan T. A. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(7):1329-1334
Protection of Metals and Physical Chemistry of Surfaces - The process of formation of protective cerium-containing conversion coatings on galvanized surfaces has been developed. It has been shown... 相似文献
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《腐蚀工程科学与技术》2013,48(4):179-186
AbstractAll types of zinc-coated steels have been painted in commercial practice for several decades; for the majority of these surfaces, simple general recommendations can be made and these have been incorporated in this paper For zinc-sprayed steel, however, there is still some research needed before completely generalised recommendations can be given. However commercial schemes which have been proved satisfactory in various environments are appropriate for all current uses and have been tabulated in paper.The rapid increase in the use of painted zinc-coated steel and an appreciation of its cost advantages is stimulating great interest in new combinations of organic materials and zinc coatings: the benefits of developments in each technology are likely to be enhanced when the materials are used in combination, and some examples are given. 相似文献
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镀锌层黑色钝化膜具有均匀的乌黑外观、良好的结合力 ;耐蚀、耐磨性也比彩色钝化、高温或常温发黑等优越得多。本文结合产品和厂情分析后采用铜盐法黑色钝化工艺 ,现作简单介绍。1 铜盐黑色钝化工艺1.1 流 程钢铁制品→前处理→电镀锌→流动水清洗× 2→锌层常规出光→流动水清洗× 2→黑色钝化处理→流动水清洗→压缩空气吹干 (或浸脱水防锈剂 )→膜层老化处理→检验成品入库→不合格件返工处理。1.2 配 方[1]硫酸铜 (CuSO4 ·5H2 O) 30~ 5 0g/L表面活性剂微量铬酐 (CrO3 ) 15~ 30 g/LpH 2~ 3甲酸钠 (CHCOON… 相似文献
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1 低铬钝化溶液的维护1.1 溶液的补充低铬钝化过程中由于溶液对基体锌层无抛光作用 ,钝化前镀层的抛光依靠浸稀硝酸来完成 ,经硝酸出光后有利除去锌层表面添加剂分解后沾附于工件表面的有机物质 ,镀件进入钝化槽后钝化液直接与光亮的锌层表面发生化学反应 ,产生钝化膜 ,因此对于溶液中各组分的消耗是甚微的 ,并由于铬酐含量低 ,溶液在镀件表面粘性小 ,随镀件带出的量也很少 ,因而溶液中有机、无机杂质的带入也大大少于高铬钝化工艺 ,相对来说溶液比较稳定 ,无需像高铬钝化那样需经常调整。经一定时间使用后如发现成膜速度逐渐减缓 ,所获得… 相似文献
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提出了氯化钾镀锌和三价铬钝化工艺,能满足大多数镀锌件的装饰、防护和不含Cr6 的要求.使用自行配制的添加剂能降低生产成本.并阐述了工艺中各组分及操作条件的影响和控制.认为溶液对钝化的影响较小,而操作条件的影响较显著.只要协调好pH、温度、时间三者关系,能稳定地获得蓝色均匀、符合要求的钝化膜.提出了钝化液中Fe3 控制的措施和处理的方法. 相似文献
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Red’kina G. V. Sergienko A. S. Kuznetsov Yu. I. 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(7):1352-1360
Protection of Metals and Physical Chemistry of Surfaces - Abstract—The ability of improving the protective properties of layers formed on zinc in the presence of sodium dodecylphosphonate... 相似文献
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总结了镀锌产品无铬钝化技术的发展状况。无铬钝化分为无机物钝化和有机物钝化两个体系,大部分工艺还处于实验室研究阶段。介绍了ZECCOAT无铬钝化工艺的应用。该工艺采用了高科技纳米技术,钝化溶液无毒,钝化膜薄,具有自修复性,耐腐蚀性高。生产实践表明,ZECCOAT无铬钝化满足汽车零配件的性能要求。 相似文献
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目的制备性能良好的封闭剂,以提高电镀锌三价铬彩色钝化膜的耐蚀性。方法以氟化钠、硅酸钠、OP为主要原料制备封闭剂。采用5%醋酸铅点滴法测定封闭处理后的电镀锌三价铬彩色钝化膜的耐蚀性能,探讨了封闭剂的配方,分析了封闭时间、烘干温度、烘干时间等工艺条件对耐蚀性的影响,并通过正交试验对封闭工艺进行了优化,确定了以氟化钠和硅酸钠为主盐的封闭剂的钝化处理工艺规范。结果试验得到的封闭剂组成为:氟化钠0.2 mol/L,硅酸钠0.05 mol/L,OP 1 m L/L。采用该封闭剂,在浸渍时间20min、烘干温度80℃的条件下,醋酸铅点滴实验最高达到近900 s。结论封闭后膜层呈彩虹色,色泽明亮,钝化膜耐蚀性提高。 相似文献
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Nucleation and growth of zinc electrodeposition in acid sulphate bath on electropolished and mechanically polished low carbon steel surfaces was investigated. On both surfaces thin η-zine crystals were stacked on each other, although their orientation was different. Potentiostatic current-time plots and cyclic voltammetry were used to study the nucleation process. The results indicated that at pH 2 the nucleation process on both surfaces um instantaneous, and that the growth process was charge transfer controlled. The growth rate on the electropolished surface was higher than the mechanically polished surface under the same electrochemical conditions. Increasing temperature did not affect the nucleation mode; it only increased the growth rate. Increasing the pH from 2 to 4 caused deviation from instantaneous nucleation, so that on the mechanically polished surface the nucleation mode was fully progressive. The reason for this behavior was attributed to the number density of active nucleation sites on the steel surface. Cyclic voltammetry also confirmed the hydroxide layer formation model. 相似文献
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不锈钢柠檬酸钝化工艺研究 总被引:5,自引:3,他引:2
研究了不锈钢柠檬酸钝化的工艺,用柠檬酸对不锈钢进行钝化处理,通过电化学技术、浸泡试验对改性后的试样进行耐蚀性测试,并运用XPS技术对表面改性后的不锈钢表面进行了微区成分分析.结果表明:钝化后,不锈钢试样表面由金属氧化物、金属氢氧化物以及少量的金属单质和结晶水组成钝化膜,其耐蚀性大大提高,点蚀电位达到1 100mV左右,在6?Cl3溶液中浸泡的腐蚀速率显著低于未钝化试样的腐蚀速率.综合考虑,不锈钢柠檬酸钝化的最佳工艺为:柠檬酸质量分数4%,温度65℃,钝化时间15min,浓硝酸后处理11min. 相似文献
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环保型镀锌产品是未来发展的必然趋势,文章阐述了镀锌无铬钝化产品的生产工艺,结合无铬钝化涂覆工艺理论,通过生产试验分析,提出了工艺优化措施及其相关的重要控制点,从而保证了无铬钝化产品涂膜质量的稳定性,并取得了明显的效果。 相似文献