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。     

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.     

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-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-SiO2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-SiO2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-SiO2复合镀层技术具有先进性,应用前景良好.     

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。     

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.     

碱性溶液添加三价铁电沉积锌铁合金

在碱性锌酸盐溶液中添加微量三价铁获得高稳定性电解液和电沉积高耐蚀性的Zn-Fe合金镀层,研究了镀液及镀层的主要工艺性能。     

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.      

Zn-Ni合金镀层中添加第三种元素和纳米颗粒的研究新进展

介绍了在汽车、航空航天等行业中得到广泛应用的钢铁零件电镀Zn-Ni合金镀层,以及往碱性、氯化物等锌镍合金镀液中加入Fe、Co、Mn、Ce、P等第三种元素所获得的锌镍三元合金镀层,具有更优良的耐腐蚀性、催化性等性能的情况。介绍了往Zn-Ni合金镀液里加入氧化硅、氧化铈、氧化钛、氧化铝、碳化硅等纳米颗粒的进展情况,发现含有纳米颗粒的锌镍复合镀层具有耐腐蚀性、耐磨损性、热稳定性更好,硬度更高等优点。梳理了2016年以来在Zn-Ni合金电镀中添加第三种元素和纳米颗粒的多层镀层研究新进展。从Zn-Ni单一镀液中沉积Ni-P和Zn-Ni合金多层镀层时,在低电流密度下沉积出Ni-P层;在较高电流密度下,沉积出含3.2%P的Zn-Ni-P合金镀层,这种多层镀层可以大幅度提高钢铁零件的防腐蚀性能。介绍了在含12%Ni的Zn-Ni镀层上镀覆Ni-Co-SiC纳米复合镀层的情况,这种多层结构既可以提高镀层的结合力,又可提高其在3.5%NaCl溶液中的耐腐蚀性能。该复合镀层是一种硬度高、磨损量低的新型Zn-Ni合金复合镀层。     

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．     

Chromate conversion coating treatments for electrodeposited zinc-iron alloy coatings from an acidic sulphate bath

The composition, microstructure and morphology of a zinc-iron alloy deposit obtained from an acid sulphate bath have been investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that under the optimised conditions, the bath produced smooth, uniform, bright, fine-grained zinc-iron alloy deposits having the desired 0.4–0.8 wt.% Fe. The zinc-iron alloy deposit was identified as h.c.p. η—phase and showed an highly preferred orientation. A low concentration Chromate treatment has been successfully developed and applied to electrodeposited zinc-iron alloy coatings with 0.4–0.8 wt.% Fe. The corrosion resistance of the Chromate conversion coatings on zinc-iron alloy deposits has been assessed using the neutral spray tests and electrochemical measurements. The results indicated that the corrosion resistance of the zinc-iron alloy deposit was significantly improved and strongly depended on iron content of the alloy deposit after Chromate passivation treatment. The composition depth-profile of the Chromate conversion coating was measured by sequential use of X-ray photoelectron spectroscopy (XPS) and sputter-etching. It was found that the major constituents of the Chromate conversion coating were zinc, chromium and oxygen, and a small amount of iron was also detected. According to analysis of the XPS data, the Chromate conversion coating on the zinc-iron alloy deposit is mainly composed of oxides and hydroxides of zinc and chromium. SEM investigation indicated that the surface morphology of the Chromate conversion coating was characterised by some ‘dried riverbed’ microcracks.     

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。     

Electroplated super-hydrophobic Zn-Fe coating for corrosion protection on magnesium alloy

A superhydrophobic Zn-Fe alloy coating was prepared on the surface of a reactive magnesium alloy using a simple, low-cost, eco-friendly method. Firstly, the Zn-Fe coating was obtained in a neutral glycerol Zn-Fe plating solution, which is green, compositionally stable, and non-corrosive to the equipment. And then the superhydrophobic surface with a flower-like microstructure was obtained by grafting myristic acid onto the Zn-Fe coating via a chelation reaction. The water contact angle was >150° and the rolling angle was 3°-4°. The corrosion rate of the two groups of superhydrophobic magnesium alloy samples with electrodeposition time of 30 and 50 min, respectively, was reduced by about 87% compared to that of the bare magnesium alloy. The prepared superhydrophobic coatings exhibit high performance in self-cleaning, abrasion resistance, and corrosion resistance.     

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.     

铁基锌镀层的腐蚀电化学研究

为寻找耐蚀性好的镀层材料及确定稀土对镀层的影响,通过弱极化区极化曲线测定和Tafel曲线测定2种电化学测试方法对Zn/Fe、Zn-Fe/Fe、Zn-Fe-Re/Fe在5%NaCl溶液中的腐蚀行为进行了测试和分析,并将腐蚀测试结果进行了比较,由比较结果可知,3种镀层的耐蚀性排序为:Zn-Fe-Re/Fe>Zn-Fe/Fe>Zn/Fe.稀土元素的存在使得镀层更加均匀、致密,镀层表面更加平整,腐蚀产物可以很好地保护基底,从而增大了耐蚀能力.     

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.     

化学镀Ni-Fe-P和Ni-Fe-P-B合金的耐蚀性研究

利用失重法和电化学测试法,对比研究以铝合金为基体化学镀Ni-Fe-P和Ni-Fe-P-B合金的耐蚀性.结果表明:这两种镀层浸泡在3.5%NaCl和10%NaOH溶液中均比浸泡在0.1mol/L H2SO4和1mol/L HCl中有更好的耐蚀性.另外,在3.5%NaCl和10%NaOH溶液中,Ni-Fe-P-B镀层合金比Ni-Fe-P有更好的耐蚀性;但是在0.1mol/L H2SO4和1mol/L HCl溶液中,Ni-Fe-P镀层合金却比Ni-Fe-P-B有更好的耐蚀性;