高耐蚀性Zn-C0合金镀层钝化工艺的研究

研究了电镀Zn-C0合金镀层的钝化液的组成及工艺条件、溶液各成分及工艺条件对钝化膜质量的影响.通过几种腐蚀试验方法,测量了钝化膜的耐蚀性.结果表明,研究的钝化工艺可以得到耐蚀性良好的钝化膜.     

Zn-Fe合金镀层黑色钝化工艺研究Ⅱ--工艺条件的优化及钝化膜耐蚀性能的研究

在钝化膜组成成分研究的基础上，详细研究了工艺条件对Zn-Fe合金钝化膜耐蚀性的影响，从而得到了最佳的工艺条件。对Zn-Fe合金钝化膜性能进行了测试，并采用5％NaCl中性溶液浸泡试验对Zn镀层、Zn-Fe合金镀层及Zn-Fe-TiO2复合镀层黑色钝化膜的耐蚀性进行了比较。结果表明，经黑色钝化后，Zn-Fe合金镀层及Zn-Fe-TiO2复合镀层的耐蚀性都有很大的提高；Zn-Fe合金镀层的耐蚀性是纯锌镀层的3倍多，而Zn-Fe-TiO2复合镀层的耐蚀性是Zn-Fe合金镀层的2倍多，是纯锌镀层的5倍左右。     

Zn－Fe合金镀层黑色钝化工艺研究Ⅰ－钝化液组成成分的优化

为了提高Zn-Fe合金镀层耐蚀性，采用非银盐发黑剂，结合磷化工艺，并加入适当的添加剂及辅助成膜剂，研制出了一种新的Zn-Fe合金镀层黑色钝化工艺。该钝化液中铬酸含量低，污染小，且化学性能稳定，使用寿命长。详细研究了钝化液中各组分对钝化膜成膜及其耐蚀性的影响，从而确定了最佳的钝化液组成。研究结果表明，采用该种钝化液获得的钝化膜油黑发亮，色泽均匀，耐蚀性及耐磨性好，附着力强。     

高耐蚀性锡锌合金镀层钝化工艺研究

本文重点研究了锡锌合金镀层(含锌25％左右)的铬酸盐钝化液中活化剂和硬化剂的作用,以及钝化工艺条件的影响。研制了比较理想的钝化液的组成和工艺条件,得到了彩虹色钝化膜,并具有良好的耐蚀性。     

MSA镀锡层无铬钝化工艺

采用钼酸盐与植酸体系对MSA镀锡层进行钝化处理,获得了色泽光亮、耐蚀性优良的钝化膜。探讨了钝化液组成及工艺条件对钝化膜耐蚀性的影响。结果表明:钼酸盐钝化膜的耐蚀性虽不及铬酸盐钝化膜的,但比镀锡层的好。     

一种钼酸盐钝化液配制与其对镀锌钢材钝化效果的初步探索

通过对钼酸盐钝化实验的研究,了解了钼酸盐对镀锌层进行钝化的工艺,探讨了钝化液组成及工艺条件对钝化成膜及膜层耐蚀性的影响。用醋酸铅溶液对钝化膜进行点滴试验,并对其结果进行了分析,得出了一些有参考价值的结论。     

三价铬钝化液的研究进展

综述了镀锌层三价铬钝化液的组成及钝化参数对钝化膜的影响,并对三价铬钝化液的组成及钝化工艺条件对钝化膜性能的影响做了详细的介绍.指出今后三价铬钝化的研究方向应该向绿色环保发展,提高钝化膜的耐蚀性,简化操作工艺势在必行.     

Zn-Fe合金镀层黑色钝化工艺研究I--钝化液组成成分的优化

为了提高Zn-Fe合金镀层耐蚀性,采用非银盐发黑剂,结合磷化工艺,并加入适当的添加剂及辅助成膜剂,研制出了一种新的Zn-Fe合金镀层黑色钝化工艺.该钝化液中铬酸含量低,污染小,且化学性能稳定,使用寿命长.详细研究了钝化液中各组分对钝化膜成膜及其耐蚀性的影响,从而确定了最佳的钝化液组成.研究结果表明,采用该种钝化液获得的钝化膜油黑发亮,色泽均匀,耐蚀性及耐磨性好,附着力强.     

锌-镍合金三价铬钝化工艺的研究

研究了三价铬钝化液的pH值对锌-镍合金钝化膜的形成机理、耐蚀性、表面形貌的影响。在三价铬钝化过程中,pH值是一个重要的工艺参数,它决定了钝化膜的生成和溶解。当钝化液的pH值过低时,钝化膜的溶解速率过快,使得钝化膜的微裂纹结构不太明显,不利于提高钝化膜的耐蚀性。当钝化液的pH值过高时,钝化液的活性下降,锌的溶解速率降低,影响钝化膜的生长,同样不利于提高钝化膜的耐蚀性。在pH值为2.0的条件下制得的钝化膜具有均匀、致密的微裂纹结构,耐蚀性良好。     

高耐蚀性镀锌白钝化后处理工艺

镀锌层经白色钝化后，中性盐雾试验出现白锈的时间仅为4h，为提高其耐蚀性，采用高耐蚀性镀锌蓝钝与封闭处理相结合，介绍了工艺过程及操作条件，分析了影响膜层耐蚀性的因素。结果表明：采用该工艺能得到白色封闭膜，中性盐雾试验48小时后不出现白锈。     

Anodic behaviour of one and two-layer coatings of Zn and Co electrodeposited from single and dual baths

One and two-layer Zn and Co coatings deposited from single and dual baths have been studied. During potentiodynamic stripping of a two-layer coating deposited from dual baths, containing either Zn2+ or Co2+, composed of a Co underlayer and a Zn overlayer, two separate peaks are observed, corresponding to the dissolution of both metals independently of one another. When the overlayer is of Co, the predominant part of the two-layer coating is stripped at the dissolution potential of pure Co coatings. In the anodic dissolution curve of a two-layer coating deposited from a single bath, containing both Zn2+ and Co2+, composed of a Zn layer with low (1.0%) Co content and a layer with high (6.5%) Co content, three anodic current peaks are observed. These are due to the dissolution of pure Zn and of Zn–Co alloy phases. The heights of the peaks and the potentials of their maxima do not depend on the order of layers but only on their thickness.     

Study of the mechanical and structural properties of Zn–Ni–Co ternary alloy electroplating

Ternary zinc–nickel–cobalt alloys were electrodeposited on steel substrates from sulfate bath by direct current. Microstructural and mechanical properties of Zn–Ni–Co ternary alloy coatings were investigated and contrasted with the characteristics of Zn–Ni and Zn–Co alloy coatings. It was found that the obtained Zn–Ni–Co alloy exhibited more preferred surface morphology and mechanical properties as compared to the other alloy coatings electroplated at the same conditions. X-ray diffraction studies showed that the deposits of Zn–Ni–Co alloy coatings consisted of Zn, ZnNi₃, and ZnCo₁₃ phases. The structure, surface morphology, and surface topography of the deposited alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS), and atomic force microscopy (AFM). In addition, hardness, elasticity modulus, and adhesion strength of coated alloys were measured with dynamic ultra-microhardness (DUH) and Scratch tester.     

Electrochemical studies of zinc–cobalt alloy coatings deposited from alkaline baths containing glycine as complexing agent

Co-deposition of Zn–Co alloy coatings that were electrodeposited from weakly alkaline glycine solutions has been studied by cyclic voltammetry. Scanning electron microscopy (SEM), energy depressive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used to study surface morphology, chemical composition, and phase structure of the coatings. Corrosion behavior of the coatings was also studied using potentiodynamic polarization tests in 3.5 wt% NaCl solution. Cyclic voltammetry results showed that in Zn–Co deposition from an alkaline bath in the presence of glycine, cobalt deposited at a potential near to that of zinc together with successful co-deposition of Co and Zn. It was also shown that reduction–oxidation (redox) reactions of Zn–Co alloy deposits were quasi-reversible and resulted in deviation of electrodeposited alloys from the equilibrium phase diagrams. The corrosion resistance of the deposits was also highly influenced by the composition and morphology of the coatings. Overall, Zn–Co deposit containing 0.89 wt% Co showed that the highest corrosion resistance among the coatings that was due to its single phase structure and fine morphology.     

Electrodeposition of Zn–Co alloy coatingsfrom sulfate–chloride electrolytes

The composition, surface morphology and appearance of Zn–Co alloy deposits as a function of current density, electrode potential and Co2+ concentration in the electrolyte was studied. It was found that coatings of good quality with low (1%) Co content are formed at a current density of 0.2Adm–2 and with high (6.5%) Co content at 2Adm–2 from electrolytes containing 1.0M Co2+ under galvanostatic conditions. The potentiodynamic dissolution of coatings with Co content of 6.5% indicates successive deposition of Co enriched phases and a pure Zn phase. The Zn–Co alloys are more corrosion resistant than zinc but are less resistant than cobalt.     

Nanocrystalline Ni–Co alloy coatings: electrodeposition using horizontal electrodes and corrosion resistance

Nanocrystalline Ni–Co alloy coatings containing 0–45 wt% Co were electrodeposited using horizontal electrodes in a modified Watts bath. Different techniques including scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, microindentation, and potentiodynamic polarization were used to characterize the alloy coatings. Properties of the alloy coatings were investigated as a function of the cobalt ion concentration (Co²⁺) in the bath. It was observed that the alloy codeposition exhibits anomalous behavior. Co content in the alloy coatings increases with increasing Co²⁺ in the bath and with electrolyte agitation. Morphology and grain size of alloy coatings are greatly affected by Co content. By increasing Co content, surface morphology of the alloy coatings changes from pyramidal to spherical. Microhardness of the alloy coatings increases with increasing Co content mainly due to decreasing grain size that follows the Hall–Petch relation. In addition, Ni–17 wt% Co alloy exhibits better corrosion resistance compared to pure Ni and other Ni–Co alloy coatings. The higher corrosion resistance of Ni–17 wt% Co coating is discussed based on its phase structure, grain size, and preferred orientation.     

锡-锌合金镀层的无铬和低铬钝化

目前，在锡－锌合金上进行铬酸盐钝化已得到广泛应用，但六价铬化合物具有很高的毒性，又是第一类致癌物质，因而现在迫切需要开发对锡－锌合金的代铬钝化工艺。主要研究了Sn-Zn合金镀层的无铬和低铬钝化处理，并改善了合金镀层的耐蚀性。     

Electrochemical deposition and characterization of ZnCo alloys and corrosion protection by electrodeposited epoxy coating on ZnCo alloy

ZnCo alloys electrochemically deposited on steel under various deposition conditions were investigated. The influence of deposition current density, temperature and composition of deposition solution on the phase structure and corrosion properties of ZnCo alloys were studied. It was found that ZnCo alloy obtained from chloride solution at 5 A dm⁻² showed the best corrosion properties, so this alloy was chosen for further examination. Epoxy coating was electrodeposited on steel and steel modified by ZnCo alloy using constant voltage method. The effect of ZnCo alloy on the corrosion behavior of the protective system based on epoxy coating is interpreted in terms of electrochemical and transport properties, as well as of thermal stability.     

ZnxCo1-xCO3碳酸盐负极材料的制备及其电化学性能研究

碳酸钴是一类典型的转换型负极锂电池材料,具有资源丰富、比容量高、安全可靠等优点,但是存在一些尚未解决的问题,例如导电性比较差,同时在锂离子的嵌入和脱出过程中体积变化严重。通过水热法制备了不同组分Zn掺杂Zn_xCo_1-xCO₃ (x=0.12, 0.3, 0.5),通过调整Zn和Co原材料质量来控制Zn/Co的摩尔比,研究表明当Zn和Co的摩尔比为0.3∶0.7时,掺杂产物有良好的循环和倍率性能,锌离子的掺杂提高了锂离子电导率,对Zn_xCo_1-xCO₃ (x=0.12, 0.3, 0.5)研究表明其在充放电过程中既有合金反应又有转换反应,提高了整个电极的导电性,进而表现出优异的电化学性能。     

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

In the present work, zinc–nickel alloy coatings have been produced under direct current conditions from an acid bath with different concentrations of diethanolamine (DEA) and triethanolamine (TEA). The produced coatings were analysed through chronopotentiometry, microhardness, X‐ray diffraction and MEB techniques. The compositional analysis of the films showed that the Zn–Ni electrodeposition is anomalous for all the systems. Ethanolamines augmented the anomalous behaviour. The hindering in the Ni (II) reduction will be more effective due to complexation of Ni (II) catalyst with ethanolamines. Electrochemical and structure analysis of deposits indicated the presence of γ and highly Zn‐enriched phases. The presence of these additives resulted also in coatings with finer grains. The behaviour of modified Zn–Ni alloy coatings in corrosion solution of 3% NaCl was investigated through potentiodynamic polarisation and electrochemical impedance spectroscopy. It was found that the obtained Zn–Ni/3 mM TEA alloy exhibited better corrosion resistance compared to pure Zn–Ni alloy electrodeposited at similar conditions. © 2012 Canadian Society for Chemical Engineering