Zn-Fe-SiO2复合镀层的性能研究

分别采用硫酸盐体系和氯化物体系的最佳工艺条件电沉积制备了高铁(Fe mass%＞1%)和低铁(Fe mass%＜1%)的Zn-Fe-SiO2复合镀层,并系统测试了不同厚度Zn-Fe-SiO2复合镀层的耐蚀性、结合力、孔隙率和氢脆性等综合性能,同时与电镀Zn及Zn-Fe合金进行了对比.实验结果表明Zn-Fe-SiO2复合镀层的耐蚀性及其它综合性能均优于Zn-Fe合金镀层和Zn镀层.因此,相对于电镀Zn及Zn-Fe合金,电沉积Zn-Fe-SiO2复合镀层技术具有先进性,应用前景良好.     

Zn-Fe-SiO2复合镀层的耐蚀性研究

采用电沉积的方法，制备了Zn-Fe-SiO2复合镀层，对比了该镀层与Zn-Fe合金镀层及Zn镀层的耐蚀性，并研究了镀层成分对镀层耐蚀性的影响，发现该复合镀层无需钝化处理即具有很高的耐蚀性，而且镀层在酸性溶液中的耐蚀性随着镀层中Fe含量的增大而提高，在中性溶液中的耐蚀性随着镀层中SiO2含量的增大而提高.      

碱性溶液锌铁合金电沉积研究

在碱性锌酸盐溶液中电沉积获取 Fe0.4—0.8%的锌铁耐蚀合金镀层。探讨了镀液成分对合金含 Fe 量的影响,含 Fe0.4～0.8%的 Zn-Fe 合金镀层的耐蚀性优于普通镀层。讨论认为 Zn-Fe 合金的共沉积为异常共沉积。     

稀土对硫酸盐体系电沉积Zn-Fe合金阴极极化的影响

为了深入地探讨Zn-Fe合金镀层的电沉积机理,实验在了三电极体系下,采用动电位法测定硫酸盐体系电沉积Zn-Fe合金镀层的阴极极化曲线,探讨了该合金镀层的电沉积机理,以及镀液成分和稀土盐的加入对电沉积阴极极化的影响.通过实验发现,Zn-Fe合金镀层的沉积属于异常共沉积,结果表明镀液中加入稀土盐Ce2(SO4)3后,对Zn-Fe合金镀层电沉积的阴极极化行为有较大影响.     

Ni-ZrO2纳米复合电镀层的制备及其耐蚀性研究

采用电镀工艺制备了纯镍电镀层和NiZrO2纳米复合电镀层,对纯镍电镀层和NiZrO2纳米复合电镀层分别在10％HCl和10％H2SO4溶液中的耐蚀性进行了对比研究,用SEM对各种电镀层腐蚀后的表面形貌进行了观察.结果表明,在脉冲条件下所制备纳米复合电镀层的耐蚀性明显优于其它电镀层,其原因是电镀层中复合有适量的纳米ZrO2颗粒以及脉冲电沉积工艺本身所致.      

Zn─Fe合金镀层耐蚀性能研究

利用X-射线衍射和扫描电镜技术研究了纯Zn和Zn-Fe合金(含Fe0.2～0.7wt%)镀层的结构,发现Zn-Fe合金镀层的晶粒较纯Zn镀层细小,晶体排布更为致密;利用电化学综合测试仪研究了纯Zn和Zn-Fe合金镀层的极化电阻和腐蚀电流,结果表明Zn-Fe合金镀层的极化电阻更高而腐蚀电流较纯Zn镀层显著减小。     

电沉积Zn-Fe-SiO2复合镀层的阴极极化

为了更深入地探讨Zn-Fe-SiO2复合镀层的电沉积机理，采用三电极体系下的动电位法测定了电沉积Zn-Fe-SiO2复合镀层的阴极极化曲线，并研究了镀液成分对阴极极化的影响。结果表明，Zn-Fe-SiO2复合镀层的沉积属于异常共沉积，而且SiO2微粒的加入对Zn-Fe-SiO2镀层复合电沉积的阴极极化行为影响不大。     

稀土对电沉积Zn-Fe-La三元合金性能影响的研究

为了获得更加光亮、致密的Zn-Fe-La三元合金镀层,针对电沉积Zn-Fe-La三元合金镀液组成及工艺条件,系统地研究了稀土对镀层成分含量、镀液稳定性、镀液分散能力以及pH值的影响,测定了镀层的极化曲线、稳定电位和极化电阻,比较了不同稀土含量对镀层耐蚀性的影响.结果表明:稀土的加入可提高镀液稳定性、分散能力,增加电沉积过程阴极极化,使阳极钝化前的活性区腐蚀电位正移,自溶解速度下降,有利于提高镀层耐蚀性,其耐蚀性比Zn-Fe合金镀层及纯Zn镀层有很大提高.     

Zn-Fe合金电镀的应用与发展

综述了各种Zn-Fe合金电镀工艺的特点及研究应用现状,重点对比研究了各种络合体系的碱性锌酸盐Zn-Fe合金电镀工艺.结果表明,含铁量≤0.8%的Zn-Fe合金镀层,可以直接经铬酸盐钝化处理而大幅度提高膜层的耐蚀性能.     

实用专利

采用以碱金属锌酸盐(如锌酸钠或别的碱金属锌酸盐)、铁的蔗糖盐为主要成分的碱性溶液进行电解沉积而获Zn-Fe合金。该合金镀层以极佳的防腐性著称。在最佳的工艺条件范围内,即槽液温度0～60℃,阴极电流密度0.1～10A/dm~2时,可电沉积出含Fe为0.05～20％Zn-Fe合金。该电镀液性能稳定,抗杂质干扰性强,电解效率高,勿须再添加别的络合剂或鳌合剂,而只用碱金属氢氧化物调整槽液的PH值。由此镀液,以最佳的工艺条件实施电解,可得到合金成分恒定的Zn-Fe镀层。 (梁俊福摘自美国专利)     

Zn-Fe合金镀层耐蚀性研究

通过改变工艺条件,可以从碱性溶液中获得含 Fe0.4～0.8%的 Zn-Fe合金镀层。试验表明这种镀层的耐蚀性是普通镀锌层的2倍。含 Fe 量不同的镀层其耐蚀性也不同。含 Fe 在0.4～0.8%的镀层在5%NaCl 溶液中在稳定电位条件下处于钝化区,而且镀层的极化电阻比较大,是镀锌层的2倍以上,而镀锌层在同样溶液中处于活化溶解区,有很大的溶解电流,而且极化电阻较小。腐蚀后形貌观察也表明 Zn-Fe 合金镀层与镀锌层的特征不同,呈花球状形貌。正是由于上述差异决定了 Zn-Fe 合金镀层的耐蚀性是优良的。     

Optimization of deposition conditions for bright Zn-Fe coatings and its characterization

Sulfate bath having ZnSO₄ · 7H₂O, Fe₂(SO₄)₃ · H₂O and thiamine hydrochloride (THC) and citric acid (CA) in combination, represented as (THC + CA) was optimized for deposition of bright Zn-Fe alloy coating on mild steel. Bath constituents and operating parameters were optimized by standard Hull cell method, for peak performance of the coating against corrosion. The effect of current density (c.d.), pH and temperature on deposit characters, such as corrosion resistance, hardness and glossiness were studied and discussed. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were used to assess the corrosion behaviors. Surface morphology, and composition of the coatings were examined using Scanning Electron Microscopy (SEM), interfaced with EDXA facility, respectively. The Zn-Fe alloy, with intense peaks corresponding to Zn(100) and Zn(101) phases, showed highest corrosion resistance, evidenced by X-ray diffraction (XRD) study. A new and cheap sulfate bath, for bright Zn-Fe alloy coating on mild steel has been proposed, and results are discussed.     

Electrodeposition of Zn-Ni, Zn-Fe and Zn-Ni-Fe alloys

Zn-Fe, Zn-Ni and Zn-Ni-Fe coatings were electrodeposited galvanostatically on mild steel from acidic baths (pH 3.5) consisted of ZnCl₂, NiCl₂, FeCl₂, gelatin, sulfanilic (p-aminobenzenesulfonic) acid and ascorbic acid. Cyclic voltammetry showed that the effect of gelatin was more pronounced than that of sulfanilic acid, and that the deposition of the ternary alloy behaved differently from the deposition of the binary alloys. In all three systems, the Faradaic efficiency was higher than 88%, the rate of Zn deposition was heavily influenced by mass-transport limitation at high applied current densities, and the deposition was of anomalous type. For each applied current density, the concentrations of Ni and Fe in the ternary alloy were higher than the corresponding concentrations in the binary alloys. The hardness of Zn-Ni coatings was the highest, while that of Zn-Fe coatings was the lowest. The Zn-Ni-Fe coatings were the smoothest, had distinguished surface morphology, and contained ZnO in the bulk, not just on the surface. The lowest corrosion rate in each alloy system (214, 325 and 26 μm year⁻¹ for Zn-Ni, Zn-Fe and Zn-Ni-Fe, respectively) was characteristic of coatings deposited at 30, 30 and 40 mA cm^− 2, respectively. The higher corrosion resistance of the ternary alloy was also reflected by a higher corrosion potential, a higher impedance and a higher slope of the Mott-Schottky line. The enhanced corrosion behavior of the ternary alloy was thus attributed to its chemical composition, phase content, roughness and the synergistic effect of Ni and Fe on the n-type semiconductor surface film.     

Zn－Fe合金电镀的应用与发展

综述了各种Ｚｎ－Ｆｅ合金电镀工艺的特点及研究应用现状，重点对比研究了各种络合体系的碱性锌酸盐Ｚｎ－Ｆｅ合金电镀工艺．结果表明，含铁量≤０．８％的Ｚｎ－Ｆｅ合金镀层，可以直接经铬酸盐钝化处理而大幅度提高膜层的耐蚀性能．     

Production of layer by layer Zn–Fe compositional multilayer alloy coatings using triangular current pulses for better corrosion protection

Abstract

Multiple-layer coatings of Zn–Fe alloy having alternatively the same compositions have been developed galvanostatically on mild steel (MS) from a single plating bath using triangular current pulses. Thiamine hydrochloride (THC) and citric acid (CA) were used as additives. Multiple-layer coatings were developed under different conditions of cyclic cathode current density (CCCD) and number of layers. Cyclic voltammetry demonstrated that the addition of THC and CA improves the deposit character by increasing the Ni content (through suppressing the deposition of Zn) via preferential adsorption on the cathode surface. The corrosion behaviours of the coatings were evaluated by electrochemical AC and DC methods. The optimum multiple-layer coating, represented as (Zn–Fe)_3.0/5.0/300, was found to exhibit about four to five times better corrosion resistance when compared with monolayer (Zn–Fe)_3.0 alloy, developed from the same bath for the same duration. Distinct phase structures responsible for interface formation between successive layers (which changes alternatively) were confirmed by X-ray diffraction analysis. Better corrosion resistance afforded by multiple-layer coating was attributed to the increased specific surface area of the coating because of layering. A synergistic effect of both structural difference between layers and individual layer thickness is responsible for enhanced corrosion resistance of the multiple-layer coatings. The formation of multiple layers and corrosion mechanism were analysed by scanning electron microscopy.     

Microstructure,Morphology and Corrosion Resistance of Electrodeposited Zinc-Cobalt Compositionally Modulated Alloy Multilayer Coatings

The morphologies and corrosion resistance of electrodeposited zinc-cobalt compositionally modulated alloy multilayer coatings produced from a sulphate bath have been investigated and reported in this paper. Various current density waveforms were designed using a computer-aided pulse plater unit to deposit zinc-cobalt alloy layers of alternate compositions from 10% cobalt to 70% cobalt. Different numbers of layers with different thicknesses were deposited by designing a variety of current density waveforms. It was shown that designing waveforms with steps to produce a gradual increase or decrease in current densities can prevent crack formation and improves the quality of Zn/Co CMAM coatings. Neutral salt spray corrosion tests showed that Zn/Co CMAM coatings have better corrosion resistance than single layer Zn-Co alloy coatings. Effects of bath temperature and agitation on the corrosion resistance of these CMAM coatings were also investigated. It was found that the best corrosion protection could be achieved for a two layered Co/Zn CMAM coating deposited at 25–30 °C from a bath with a high rate of agitation.     

烧结钕铁硼电镀锌铁合金工艺与耐蚀性能

采用弱酸性氯化物镀液在钕铁硼基体上制备了高耐蚀性的锌铁合金镀层,讨论主要工艺参数对镀层铁含量的影响,优化工艺条件。采用盐雾试验(NSS)、SEM和电化学方法研究镀层的耐蚀性能和耐蚀机理。结果表明,优化工艺条件后合金镀层含铁质量分数为0.92%,钝化后在质量分数3.5%的Na Cl溶液中出白锈时间达到196 h。合金镀层对钕铁硼基体起到阳极保护的作用,镀层结晶致密,填补了钕铁硼基体的固有缺陷,同时又为获得致密的钝化膜创造了条件,减少了镀层表面的缺陷,使镀层整体具有极高的电阻,提高了其耐蚀性能。     

Ni-P-PTFE-SiO2化学复合镀工艺研究

运用化学复合镀技术,在Ni-P合金镀液中添加PTFE及SiO2粒子进行试验,获得了Ni-P-PTFE-SiO2复合镀层.对复合镀的工艺及复合粒子PTFE和SiO2的添加量进行了研究分析;通过金相显微组织、显微硬度,结合强度和镀层孔隙率等测试对Ni-P-PTFE-SiO2化学复合镀层性能进行了表征.结果表明:当PTFE粒...