Molybdate Based Passivation of Zinc

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.     

Cerium-Containing Solution for Chromate-Free Passivation of Zinc Coatings

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...     

Painting of Zinc Surfaces

Abstract

All 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.     

铜合金的铬酸盐钝化及其代替工艺的新进展

论述铜合金的各种类型钝化工艺,着重介绍低铬和非铬酸盐钝化工艺技术的新进展,并对钝化膜的质量控制进行了讨论。     

镀锌层三价铬钝化剂的探讨

适应保护环境的要求,研究了镀锌层三价铬钝化技术,在国内外一些典型的三价铬钝化配方基础上,试验研究发现,要获得良好钝化膜选用适当的络合剂是关键,并研制出能获得高耐蚀性钝化膜的三价铬蓝白钝化剂及彩色钝化剂,该钝化剂使用寿命长,镀液成份稳定,并得到了应用厂家的验证.     

铜盐黑色钝化

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…     

热镀锌层钛盐钝化膜耐蚀性能的研究

以钛盐为主盐,加入双氧水、硝酸(磷酸)、络合剂等配制无铬钝化液,经钝化后在镀锌层表面获得一层均匀的无铬钝化膜.通过电化学试验、盐雾腐蚀试验、大气暴露试验等测试手段对比研究了铬酸盐钝化膜、钛盐钝化膜、镀锌层的耐蚀性能以及影响钝化膜耐蚀性的因素.结果表明:镀锌层经钛盐钝化后耐蚀性能明显改善,在中性盐雾箱内可以通过48 h连续喷雾而不产生白锈.     

镀锌低铬钝化溶液的维护与操作

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…     

镀锌层无铬(Ⅵ)钝化的现状与发展趋向

概述了国内外镀锌层无铬（Ⅵ）钝化工艺的新进展，包括三价铬钝化、钼酸盐钝化、钨酸盐钝化、钛盐钝化、单宁酸钝化、植酸钝化．亡艺，及在研究上有较大进展的改性硅酸盐钝化、稀土金属盐钝化、有机硅烷钝化及无机-有机物复合型钝化等工艺。并在此基础上进一步提出了镀锌层无铬钝化的发展方向。     

氯化钾镀锌及三价铬钝化工艺的应用

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.     

热镀锌钢板钝化工艺研究

对热镀锌钢板钝化工艺进行了研究 ,探讨了钝化膜外观和性能的影响因素。对钝化液成分组成进行优选 ,确定了适宜的钝化液配方和工艺条件 ,可获得令人满意的钝化膜外观和较高的抗蚀性能     

锌镀层钝化处理的研究现状及展望

介绍了锌镀层铬酸盐钝化和三价铬钝化的原理及应用前景;分别概述了高铬钝化、低铬彩色钝化、低铬蓝白钝化、军绿色钝化的优缺点;重点介绍低铬钝化和三价铬钝化的发展,并进行了展望.     

Two-Stage Passivation of Zinc by Solutions of Sodium Dodecylphosphonate and Trialkoxysilanes

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...     

镀锌层无铬钝化技术研究进展

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。     

电镀锌三价铬彩色钝化膜封闭剂的制备

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。     

1060 铝化学镀镍直接置换锌前处理工艺

探讨了在铝基体上化学镀镍-磷合金镀层的工艺中,采用酸性条件下直接置换锌进行前处理的可行性,并用正交实验法对该预处理工艺进行了优化。结果表明:当置换时间为10 s,HF用量为10 mL/L,置换温度为25℃,OP乳化剂用量为20 mL/L时,施镀后,可得到厚约38μm,硬度约503HV,且与基体结合良好的高磷镍-磷合金镀层。     

Nucleation and Growth of Zinc Electrodeposited onto Electropolished and Mechanically Polished Steel Surfaces

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.     

不锈钢柠檬酸钝化工艺研究

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.     

镀锌无铬钝化产品生产工艺优化

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。     

电沉积镀镍层的无铬钝化工艺

采用正交试验法筛选了一种以植酸、钼酸钠和缓蚀添加剂为基本组成的无铬钝化液。通过电化学阻抗谱测试,确定了最佳成膜时间;通过5%CuSO4点滴试验、10%NaCl浸泡试验和极化曲线测试,对电沉积镀镍层无铬钝化后的耐蚀性能进行了研究。结果表明,采用本无铬钝化工艺后,镀镍层耐蚀性能良好。