全光亮碱性锌酸盐镀锌工艺研究

在碱性锌酸盐镀锌基础液中加入自制光亮剂XY-03A,研究成功了一种全光亮碱性锌酸盐镀锌工艺,确定了电镀工艺规范,采用霍尔槽试验探讨了主要成分对镀层质量的影响,检测了镀液和镀层性能,结果表明：所形成的锌镀层光亮度高,镀层结晶细致,与基体结合力好;镀液的分散能力、复盖能力、电流效率和镀层耐蚀性优于DE型镀锌工艺,具有较高的应用价值.     

Second Three-Day Conference on Printed Circuitry March 1980

The costly effluent disposal of alkaline cyanide-based electrolytes coupled with more stringent pollution laws has led to the appraisal of possible alkaline alternatives for the electrodeposition of zinc. Of these, zincate-based formulations appear to be promising.

This review examines their present day use, solution electrochemistry, mechanism of deposition and the properties of zinc coatings formed from them. An appraisal of their effectiveness when compared to normal cyanide solutions is also made.     

Investigation of high-performance acid zinc nickel electrolyte

Zinc nickel alloy coatings are increasingly demanded by the automotive industry due to their highly improved corrosion protection over pure zinc and other zinc alloy coatings. To produce zinc nickel coatings with a nickel incorporation of 12 to 16%, mainly alkaline zinc nickel electrolytes are used in the plating industry. Continuous improvements in the field of acidic zinc nickel alloy electrolytes now meet the needs of the automotive industry while being advantageous in specific fields of application.In this paper, zinc nickel coatings deposited from alkaline as well as from ammonium-free acid zinc nickel electrolytes are investigated. The morphology is evaluated by scanning electron microscopy; the texture is investigated by focused ion beam, and X-ray diffraction patterns identify the structure of the coating. The corrosion protection of the zinc nickel coatings and the adhesion of the zinc nickel coatings have been bench-marked. For applications on fasteners, the coefficients of friction have been measured and compared.     

Bright Nickel and Levelling Power

In the course of our researches we have studied the cathodic phenomena which lead to blight deposits from nickel baths. The action of organic brighteners has been considered as due to the possibility of some functional groups in the organic molecule interacting with free orbitals of the nickel ions, thus minimizing the size of crystalline growth centres in the process of electrodeposition. Neutralisation of these functional groups is almost always followed by the disappearance of the brightening action as has been shown with N—alkyl substituted saccharin.

The fully brightening action of some amine oxides shows, however, that the possibility cannot be excluded that cathodic reduction of the addition agent may play an important part in the cathodic deposition process.

For the purpose of studying the levelling power of solutions giving bright deposits we have developed a metallographic method which makes use of a particular micro-profile of pseudosinusoidal shape. By plotting graphically the amplitude of tile pseudosinusoidal deposit versus its thickness on the peaks of the profile it is possible to effect a quite definite comparison between the levelling power of various electrolytes containing different organic addition agents.

Experimental considerations lead to the conclusion that levelling action may he the result of a differential adsorption of addition agents in the diffusion layer on the cathode surface. This fact may cause a differential inhibition which would then favour a faster deposition in the valleys than on the peaks of the profile.     

席夫碱基季铵盐型双子表面活性剂对碱性锌电极电化学性能的影响

目的选择席夫碱基季铵盐型双子表面活性剂作为电解液添加剂,改善碱性锌电极的电化学性能,提高其耐蚀性能。方法通过电化学分析法,如失重法、塔菲尔极化曲线法、交流阻抗法等分析研究三种席夫碱基季铵盐型双子表面活性剂(D1、D2、D3)对锌电极电化学性能的影响,利用X射线光电子能谱(XPS)和扫描电子显微镜(SEM)研究在6 mol/L KOH电解液(饱和ZnO)浸泡48 h后,锌片表面的成分和形貌。结果室温下,缓蚀率随席夫碱基季铵盐型表面活性剂浓度升高而增加,当浓度进一步增大,缓蚀率变化不大。三种席夫碱基表面活性剂中,D3缓蚀能力最强,缓蚀率最高达95.67%,抑制腐蚀的效果顺序为:D3D2D1,属于抑制阳极型缓蚀剂。结论 D1、D2、D3作为碱性锌电极的电解液添加剂,可以有效减缓锌电极的腐蚀、变形、钝化及枝晶形成的能力,改善了碱性锌电极的电化学性能,D1、D2、D3适合作为碱性锌电池的缓蚀添加剂。     

A Study of the Theory Involved in the Deposition of Chromium

Reaction products of aldehydes and amines have been shown to be capable of acting as brightening agents in the electrodeposition of tin from acid solutions. A reproducible method of preparing a stable brightening agent from o-toluidine and acetaldchyde has been devised and the use of this agent in a stannous sulphate electrolyte containing cresolsulphonic acid and sodium n-octyl sulphate has been developed. The plating bath, after working in, gives fully bright, ductile deposits at current densities of 10 A/ft² upwards with slow cathode movement.     

光亮硫酸盐镀锌工艺研究

采用霍尔槽试验对硫酸盐镀锌光亮剂、载体光亮剂、辅助光亮剂进行筛选,研究成功了一种光亮硫酸盐镀锌工艺,探讨了主盐、缓冲剂、工艺条件的影响。检测了镀液、镀层性能。本工艺所得镀层光亮、细致,操作电流密度范围宽,适用于板材、线材、带材等形状简单零件的镀锌。     

光亮碱性Zn-Al合金电镀工艺研究

在碱性锌酸盐镀锌液中加入铝盐，研究成功了一种光亮碱性锌铝合金电镀工艺。采用霍尔槽试验探讨了镀液成分和工艺条件对镀层质量的影响，检测了镀液和镀层性能。研究结果表明：镀液阴极电流效率达到80%以上，镀液分散能力和复盖能力好，镀层中铝含量为1．5％左右，所形成的Zn-Al合金镀层结晶细致、光亮度好、结合力好、耐蚀性优良，适用于作高耐蚀性镀层。     

A novel electrolyte for the high speed electrodeposition of bright pure tin at elevated temperatures

A new tin electroplating process capable of producing fully bright, pure tin deposits from an electrolyte operated at temperatures of up to 50°C has been developed. Unlike conventional bright tin deposits, the tin deposit from the new process has an increased grain size and low carbon content. In addition, the deposit demonstrates excellent ductility, solderability, and low tendency for whisker growth. Production trials conducted by various industries have proven that the new pure tin deposit is suitable for connector applications, as well as for corrosion protection and decorative uses. In this article, the characteristics of the tin electrolyte and the bright tin deposit are described.Electrodeposition of bright tin, characterized by its silvery-white decorative appearance, excellent solderabilty, conductivity, good corrosion and tarnish resistance, and non-toxic nature, has been widely used in the electronic industry and protective-decorative applications. The industrial importance of tin electrodeposition has been markedly extended with the introduction of lead-free solder in the electronic marketplace. However, certain drawbacks of commonly used bright tin plating processes have limited the acceptance of electrodeposited bright tin. The operation and control of bright tin plating solutions is more difficult compared to that of matte tin processes, since the additive system of conventional bright tin electrolytes usually contains many volatile organic components that act as brightening agents. Because of the volatile nature of the organic brightening agents, a cooling system is usually required in conventional bright tin plating baths, in order to maintain the bath temperature between 20 to 25°C where most brightening agents are effective. For high-speed plating, the use of a cooling system becomes essential since the bath temperature naturally rises rapidly during plating. A key concern with the use of bright tin in certain applications is the relatively low ductility often associated with bright deposits and the reportedly higher tendency towards tin whisker growth compared to matte deposits. For demanding automotive applications, where the use of bright tin-lead has been permitted for a limited period of time, continuing efforts are being made by both the electronics industry and suppliers of plating chemistry to replace bright tin-lead with bright pure tin. Tin whisker performance has become one of the most critical characteristics in qualification of any bright pure tin plating process for use in the electronics industry.The newly developed plating bath, SOLDERON? BHT-350 bright tin, has been designed to be operated at temperatures between room temperature and 50°C, while producing ductile, bright deposits with low whisker growth tendency. Production trials conducted by different industries have demonstrated that the new process is able to produce bright tin deposits under high speed reel-to-reel plating conditions, and the simple additive system facilitates automatic or manual dosing during operation. The resulting bright tin deposits are suitable for connectors, contacts, wire and other items requiring a bright tin finish. In this article, the characteristics of the electrolyte and the properties of the bright tin deposit, including microstructure, carbon content, ductility, texture, solderability and whisker performance are described in detail.     

A New Development for the Electrolytic Deposition of Zinc-Nickel Alloy with 12–15% Nickel from an Alkaline Bath

Up to now zinc-nickel solutions with 10–16% of Ni in the deposit were only known from acid electrolytes. Those systems have the disadvantage of poor metal-distribution. On the contrary, systems from alkaline electrolytes give a good metal-distribution, however, these Zn-Ni solutions only produce 6–8% Ni in the deposit.

A new alkaline system is described that permits deposition of 13–15% Ni from a Zn-Ni-solution. The parameters and characteristics of this process are described, as well as the characteristics of the deposit with a view to its corrosion resistance before and after chromating.     

壳聚糖及其衍生物在金属缓蚀剂方面的研究应用综述

壳聚糖是一种含有大量的伯羟基、仲羟基以及氨基和糖酐键等极性官能团和孤对电子的碱性多糖。它作为一种绿色环保、廉价易得、可生物降解且具有大量活性官能团的天然高分子产物,在许多领域都有广泛的应用。综述了近年来国内外壳聚糖及其衍生物在金属腐蚀领域的研究进展,阐述了其作为缓蚀剂防腐方面的优势,并对其研究现状及机理进行了说明。简述了壳聚糖高分子结构特性及作为金属缓蚀剂的特点,分析了壳聚糖缓蚀剂的作用机理。介绍了壳聚糖衍生物的制备方法,根据官能团的不同进行了分类归纳,包括羧甲基类壳聚糖、席夫碱类壳聚糖、季铵盐类壳聚糖等,并对比了不同壳聚糖及其衍生物在不同腐蚀环境下的缓蚀效率。同时,梳理了壳聚糖及衍生物在防腐方面应用所存在的问题,如在中性条件下溶解性差、部分壳聚糖衍生物合成方法复杂等。最后,展望了壳聚糖及其衍生物在防腐领域的发展趋势。     

Corrosion behavior of phosphorus containing zinc alloy deposits obtained from alkaline electrolyte

Zinc‐alloy depositions are now largely used thanks to their good corrosion behaviour (as compared to zinc depositions). Phosphorus was introduced in the metallic matrix in order to increase the corrosion resistance of Zn‐Ni platings. Strongly alkaline electrolytes were used (pH=12‐12.5), in order to obtain Zn‐Ni‐ P deposits. The characteristics of these depositions (chemical composition, structure) were studied in correlation with their performances of corrosion resistance. The qualitative analysis carried out by X‐ray diffraction revealed that as part of Zn‐Ni alloy, P reduces the grain size, also bringing about a tendency towards an amorphous crystal lattice.     

Electrodeposition of Copper on Mild Steel: Peculiarities of the Process

The process of electrodeposition of copper coatings on a mild steel substrate was analyzed. The reasons for poor adhesion of the coatings from acid and alkaline cyanideless electrolytes were determined. It was shown that the problem of the direct copper coatings’ electrochemical plating on a steel substrate from cyanideless electrolytes results from the presence of the adjoint process of contact exchange in a copper ions–iron system. Good adhesion coatings can be developed only on termination of the contact exchange at the initial stage until the steel substrate under the sediment pores is not subjected to significant etching. In acid electrolytes, the adhesion is poor because of a large value of the contact exchange current. In alkaline cyanideless electrolytes iron is passivated, and adhesion of the coating is insufficient because of the presence of a separating passive film at the substrate–coating interface. In neutral electrolytes, it is possible to obtain a coating with a good adhesion to the substrate, but the results are not stable due to a low buffer capacity of the solution. During the deposition of a copper coating from acid electrolytes using a prenickel-plating, a thin nickel sublayer has pores through which the process of the contact exchange occurs. It is shown that, in order to develop coatings with a good adhesion, the minimum thickness of the nickel sublayer must be 3–5 μm.     

Electrochemical behaviour of lead alloys as anodes in zinc electrowinning

Abstract

The electrochemical and corrosion properties of the ternary and quaternary lead alloys Pb–0·18Ag–0·012Co, Pb–0·2Ag–0·06Sn–0·03Co, and Pb–0·2Ag–0·12Sn–0·06Co (wt-%) have been investigated. The formation of oxide layers on the surface of these alloys was traced by cyclic voltammetric methods and the composition of the anodic oxide layers was determined by X-ray and SEM analyses. The cobalt inclusions reduce the anodic polarisation and improve the corrosion resistance of the alloy. The Pb–0·2Ag–0·12Sn–0·06Co alloy displays electrochemical and corrosion properties similar to those of Pb–1Ag and can be used as a substitute for the latter as a material for anodes in the electrowinning of zinc from sulphate electrolytes.     

Inhibition of cooper and zinc dissolution with 5(6)-nitrobenzoimidazoles in phosphate electrolytes

Effects of the concentration and chemical structures of 2-substituted 5(6)-nitrobenzoimidazoles (5(6)-NO₂-2-R-BIs) on the dissolution of copper and zinc in phosphate electrolytes were studied. Introduction of the nitro group into benzoimidazole derivatives was found to make them more effective for copper but less effective for zinc; this is due to an increased degree of dissociation of the nitro derivatives and the possibility of ionic bonding in their complexes. The protective effects of 5(6)-NO₂-2-R-BIs on copper and zinc depend on their chemical structures and are accurately described by the equation log γ = α ± ρσ₁. The sign and magnitude of ρ indicate that electron-withdrawing substituents in 5(6)-NO₂-2-R-BIs enhance the protection of copper, while electron-donating ones enhance the protection of zinc; this is due to different abilities of these metals to form σ-and π-bonds in their complexes. Original Russian Text ? Yu.I. Kuznetsov, L.P. Podgornova, 2006, published in Zashchita Metallov, 2006, Vol. 42, No. 1, pp. 76–82.     

Effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋） on the electrochemical synthesis of polyaniline in nitric acid electrolyte

The effects of alkaline cations （M^＋ = Li^＋, Na^＋, K^＋, Cs^＋）on the electrochemical synthesis of polyaniline were carfled out under cyclovoltammetric conditions using nitrates of Li^＋, Na^＋, K^＋, and Cs^＋ as the supporting electrolytes. The results show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreases from the fast scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration of alkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also depends on the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the effect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is further lower than that of W. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electrosynthesis. Therefore, this is exactly what SEM images show： a relatively rough fibrous structure in the case of Pani-H^＋ suggesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M^＋.     

氯化物镀锌光亮剂的使用

详细阐述了氯化物镀锌工艺中光亮剂的使用、选择、添加量、使用注意事项及常见故障排除等。     

Corrosion-electrochemical behavior of iron family silicides in various electrolytes

Basic regularities of the anodic dissolution and cathodic behavior of iron family silicides in acidic and alkaline electrolytes are considered. The effect of external and internal factors on the mechanism and kinetics of the anodic process is studied using a combination of electrochemical, analytical, and structural methods. The silicides are shown to have a high chemical resistance in oxidizing and nonoxidizing acids, except for environments containing fluoride ions. The mechanisms of the anodic dissolution of silicides in acidic and alkaline environments and in fluoride-containing electrolytes substantially differ. In acidic electrolytes, metal selectively dissolves from the silicide sublattice, while silicon remains on the surface and forms a SiO₂ film, which has a high resistance in fluoride-free environments. Later, the process is limited by the diffusion of metal atoms from the bulk of the silicide toward the surface layer and the diffusion of oxidized metal through the film of hydrated silicon hydroxide. In alkaline electrolytes, the solubility of silicon and silicon dioxide sharply increases, and the kinetics of the anodic process is determined by the formation of protective films composed of oxides and hydroxides of the metal component of silicides. The films passivate the surface and make the silicides stable against alkalis. In a number of cases, the lower silicides reveal electrocatalytic properties in the cathodic process.     

无氰碱性锌酸盐镀锌光亮剂的研究

回顾我国无氰碱性锌酸盐镀锌光亮剂20年来的发展状况;介绍一种能在无氰碱性锌酸盐镀锌体系中产生镜面似的高光亮镀锌层的光亮剂——WD90A。通过电化学方法的测试,结果表明该光亮剂的作用机理符合电镀添加剂的经典理论。     

Electropolishing behavior of pure titanium in sulfuric acid–ethanol electrolytes with an addition of water

The electropolishing behavior of commercially pure Ti was studied in sulfuric acid–ethanol electrolytes with a small amount of H₂O. The experimental results showed that commercially pure Ti could be electropolished well in the 3 M H₂SO₄–ethanol electrolyte, while inadequately electropolished in 0.5 and 1 M H₂SO₄–ethanol electrolytes. However, the brightening effect on the Ti surface could be clearly observed by the addition of a few volume percent of H₂O to the 0.5 and 1 M H₂SO₄–ethanol electrolytes. The effect of a small amount of H₂O in the H₂SO₄–ethanol electrolytes on the electropolishing behavior of pure Ti was discussed.