影响大型无隔板镁电解槽电流效率的主要因素

以镁法海绵钛生产工艺中大型无隔板镁电解槽的实际运行状况及各项操作控制为依据,论述了影响无隔板镁电解槽电流效率的最主要影响因素是电解质温度、氯化镁浓度、出渣和电解质水平,总结归纳了降低槽温的各种手段和出渣应遵循的原则,并指出了采取机械出渣是实现高电流效率的必要条件。     

Bi-Cu film deposition in aqueous solutions

The relatively uniform bismuth-copper film was electrodeposited between −15 and −20 mV in the sulfate electrolyte containing 4 mmol/L bismuth ion and 2 mmol/L copper ion. Only copper was electrodeposited at −5 mV. The dendritic bismuth-copper film was electrodeposited under −20 mV. The cathodic current became constant between −20 and −400 mV. Therefore, bismuth-copper electrodeposition changes from charge transfer controlling to diffusion controlling at −20 mV. On the other hand, the uniform bismuth-copper film was electrodeposited between −5 and −35 mV in the methanesulfonate electrolyte containing 4 mmol/L bismuth ion and 2 mmol/L copper ion. The dendritic bismuth-copper film was electrodeposited under −35 mV. The potential region for good electrodepositon in methanesulfonate electrolyte is wider than that in sulfate electrolyte. Therefore, it is easy to control electrodeposition conditions by using methanesulfonate electrolyte.     

大气中SO_2对金属银的电化学腐蚀行为

利用三电极电化学电池研究了大气环境中的SO2对金属银的腐蚀行为。通过电化学阻抗谱和极化曲线分析了金属银在不同厚度液膜、不同湿度、不同SO2气体浓度及不同暴露时间下的初期腐蚀行为。结果显示:电极表面液膜越薄,金属银的腐蚀电流密度越大;采用镜头纸控制银电极表面液膜厚度,随着大气环境湿度的增加,银的腐蚀速度减小;在自然大气环境中,随着大气中SO2浓度的增加,暴露时间的延长,银电极的阻抗值增大,这可能是由于银电极表面Ag2O、AgOH和亚硫酸银等反应产物膜的形成的原因。     

Evaluating and monitoring nucleation and growth in copper foil

The electrodeposition of copper foil for use in electronic materials applications is a complex and demanding process. The specific aspects of producing and controlling the structure-property-performance requirements of the foil are important because of the stringent demands placed on their use in printed circuit boards and similar products. In this paper, a brief review of the electrodeposition process for raw copper foil is presented. Since electrolyte additives play such a significant role in the copper-depositionprocess, the effects of two essential additives, chloride ion and an organic (e.g., glue or gelatine), on the foil are described. Also, the influence of other operating parameters on the initial nucleation, growth, and subsequent electrocrystallization are discussed. Selected characterization methods, such as polarization and scanning electron micrography techniques, are described as a means of monitoring the process, but universally accepted methods of evaluating and controlling the additives and foil quality during electrolysis are still being sought.     

利用脉冲电铸技术制备含纳米颗粒的梯度功能材料

为探讨利用脉冲电沉积技术制备含有纳米颗粒的梯度功能材料,分析了脉冲电沉积过程中的主要工艺参数,研究了占空比对复合电铸层表面形貌的影响,通过控制电沉积时间和镀液中纳米ZrO2悬浮量制备了纳米复合电铸层,并对其横截面进行了SEM观察和组成成分测定.结果表明:通过控制脉冲复合电铸过程中的工艺参数可以制备出由纳米颗粒复合量变化而导致其组织成分呈梯度分布的纳米功能梯度材料,由此得到利用脉冲电铸技术制备含有纳米颗粒的FGM的新工艺.     

高锰离子电解液批量生产0#锌的技改实践

通过科学合理的技术改造,并经实践证明在1#锌品级率达98%的基础上,控制好电解液中的[Mn2＋]含量,改造沉淀混合池,减少电解槽中的Mn元阳极泥,控制大流量,合理用好添加剂,降低锌片含铅,稳定批量生产0#锌锭,品级率从不到2%达到24%。     

LSGM固体电解质薄膜制备的研究进展

Sr和Mg掺杂的稀土钙钛矿型氧化物LaGaO3(LSGM)是具有广泛应用前景的固体电解质材料.本文综述了LSGM薄膜制备的主要方法,讨论了各种方法的优缺点,最后对LSGM薄膜制备方法的进一步研究方向进行了展望.     

铜电解添加剂的工业监控

研究了铜电解精炼过程中添加剂工业监控的原理和方法.研究结果表明:阴极过电位是电解液性质的实时反映,通过阴极过电位的工业监控可得出不同电解条件时,添加剂最佳量的控制,从而在复杂铜电解过程中使高纯阴极铜生产的稳定性提高了6%;平均电流效率提高了1%.     

防污铜合金研究

船舶受到海生物污染,其航速降低,油耗增加。一般常用的防污方法有;电解海水、防污漆和防污铜台金。本文介绍了防污钢合金的研究结果及其在海洋工程中的应用。     

砷化氢析出电势的探讨

据热力学参数,计算得到砷酸、亚砷酸、单的出砷化氢的标准平衡电势值分别为０．１４４Ｖ,０．００５Ｖ,－０．２３８Ｖ。在铜电解液净化工序中,砷酸优先于亚砷酸析出砷化氢,当阴极电势足够负时,帮人同放电析出砷化氢。计算结果与实测结果基本吻合,均表明砷化氢析出的标准平衡电势值正于－０．６０８Ｖ。在铜妆液工序中,采用控制阴极电势脱部胂电积法,能有效抑制砷化氢的析出。     

Influence of Electrolyte Concentration on Copying Accuracy of Precision-ECM

A precision ECM process, dimensional accuracy ± 2 μm, surface finish 0.01 μm R_a has been developed using narrow inter-electrode gaps (< 50 μm) for mass production of small (100 mm²) component parts. The electrolyte properties, especially the concentration, play a significant role in controlling the dimensional accuracy of precision-ECM. The relationships between the electrolyte concentration and various process parameters are derived empirically and are utilised in a graphical model to predict the localisation effects of electrochemical dissolution. By controlling the localisation effects significant improvements are made to the dimensional accuracy obtained. Practical examples are used to validate the model developed.     

Kontaktkorrosion bei ein- und mehrschichtigen Metallüberzügen

Contact corrosion with one-layer and multilayer metal coatings Contact corrosion on metallic coatings depends on a number of factors which contribute to the difficulty encountered in predicting the progress of corrosion. With metallic coatings the free surface of the base material is normally small by comparison to that of the coating, so that contact corrosion — appearing as locally increased attack, possibly induced by protective measures — comes to bear on the base material only. Excluding some few exceptions the contact corrosion is controlled by the oxygen content of the attacking electrolyte, which — in addition to the type of electrolyte and the metal combination involved — determines the progress of contact corrosion. On the example of sulphur containing and sulphur-free nickel and of electrolytically deposited metals with heavily disturbed lattice it is shown, that the establishment of the contact corrosion potential is controlled by the composition and the condition of the metals involved. With galvanic Ni+Cr coatings the direction of the current in the galvanic element controlling contact corrosion may change with the composition of the attacking electrolyte, even during atmospheric corrosion, so that Cr may either be the anode being dissolved, or the cathode. It may happen that this combination does not yield any element at all, affecting the corrosion process. Model experiments serve to demonstrate the influence of the electrolyte composition and the composition of the metals in contact with each other.     

Influence of oxide layer on carbon diffusion during anode plasma electrolytic carburizing

This study is devoted to the effect of the oxide layer formed upon anodic plasma-electrolytic carburization on the rate of carbon diffusion in low carbon steels upon application of an aqueous solution of ammonium chloride with glycerol as a working electrolyte. Approximate determinations of carbon distribution in the surface layer of low carbon steels after their anodic plasma-electrolytic carburizing confirmed the hypothesis that there is deceleration of carbon diffusion by the oxide layer. Different structures of the oxide layer were revealed that depend on the method of sample cooling after their saturation with carbon in an anodic vapor-gas envelope. A possibility of controlling the thickness of the oxide layer was shown, as well as clarification of the surface by the choice of an electrolyte and treatment mode, was shown. A reduction in the roughness of the carburized surface from 0.62 ± 0.02 to 0.22 ± 0.02 μm was revealed.     

控制阴极电势电积法脱铜砷

在净化铜电解废液工艺流程中，控制阴极电势值，使铜砷优先析出，并抑制氢气与砷化氢的析出，以达到净化电解液的目的。控制阴极电势脱铜砷电积法的脱铜电流效率达到８０％以上，电积后液中铜含量小于０．５ｇ／Ｌ，砷含量小于１ｇ／Ｌ，该方法具有节能与环保双重效益。     

数控电解磨削ST10CH硬质合金试验研究

硬质合金具有高硬度、高强度和高耐磨等特点,传统的机械加工方法难以对其加工,现采用数控电解磨削方法对型号为ST10CH硬质合金进行加工试验研究,在分析电解液浓度、加工电压、电解液压力、进给速度、主轴转速等因素的基础上,通过正交试验对其优化,得到加工该材料的优化参数,并用优化后的参数分别对电解液温度和进给速度进行单因素试验,最终得到加工该材料的成形规律。     

The influence of plasma-solution treatment on the properties of hemp fiber lignin

The effect of an atmospheric pressure gas discharge generated inside an electrolyte solution on hemp lignin has been investigated by the methods of IR spectroscopy. It is shown that the gas-discharge activation causes a threefold increase of the lignin solubility with the further chemical treatment. The feasible processes of the interaction of the active particles generated in the electrolyte solution under the discharge action with the lignin macromolecules are considered.     

大气腐蚀电化学研究方法现状

综述了大气腐蚀的电化学研究方法，尤其是薄液膜下 的电化学交流阻抗(EIS)和Kelvin探针技术的应用，比较了不同方法的优缺点.EIS比较适合 于研究薄液膜下金属的腐蚀历程；Kelvin探头适合于研究金属表面的局部腐蚀.最后展望了 大气腐蚀的研究趋势.     

Experimental investigation into electrochemical micromachining (EMM) process

Due to several advantages and wider range of applications, electrochemical micromachining (EMM) is considered to be one of the most effective advanced future micromachining techniques. A suitable EMM setup mainly consists of various components and sub-systems, e.g. mechanical machining unit, micro-tooling system, electrical power and controlling system and controlled electrolyte flow system etc. have been developed successfully to control electrochemical machining (ECM) parameters to meet the micromachining requirements. Investigation indicates most effective zone of predominant process parameters such as machining voltage and electrolyte concentration, which give the appreciable amount of material removal rate (MRR) with less overcut. The experimental results and analysis on EMM will open up more application possibilities for EMM.     

Direct nickel electrodeposition on magnesium alloy in pyrophosphate electrolyte

Direct nickel electrodeposition on a Mg alloy, AZ31B, was conducted in an electrolyte containing potassium pyrophosphate, nickel sulfate, potassium fluoride and ammonium hydroxide. The effect of potassium fluoride on the Mg alloy in a pyrophosphate nickel electrolyte was investigated using polarization and EIS methods. The chemical state of the Mg alloy was also analyzed by XPS. The effect of added ammonium hydroxide on electroplated nickel layer was observed by FE-SEM. A magnesium fluoride film, which was formed by added potassium fluoride, inhibits the dissolution of the Mg alloy in the electrolyte. The current efficiency was increased and surface cracks on the nickel layer were also eliminated by adding ammonium hydroxide to the electrolyte. The direct nickel electrodeposited Mg alloy showed significantly improved corrosion resistance compared to the uncoated Mg alloy. A successful and protective electrodeposited nickel layer was formed on the Mg alloy in pyrophosphate nickel electrolyte due to the addition of potassium fluoride and ammonium hydroxide.     

Influence of vibration on micro-tool fabrication by electrochemical machining

Recent trend in societies is to have micro products in limited space. Efficient micromachining technologies are essential to fabricate micro products which in turn will be helpful in saving material, energy and enhancing functionality. For micromachining, micro tool is very much essential. This paper is aimed at finding the most suitable and quickest method of micro tool fabrication by electrochemical machining. Tungsten micro tools were fabricated at different machining conditions to know the influences of voltage, frequency of tool vibration, amplitude of vibration of tungsten tool, concentrations of electrolyte and dipping length of tool inside the electrolyte. Fabrication of uniform diameter of micro tool is possible at each applied voltage starting at 2 V to higher volt utilizing vibration with appropriate amplitude. Good quality micro tools with different shapes can be fabricated by controlling a proper diffusion layer thickness within a very short time introducing the vibrations of micro tool. Finally, the fabricated micro tools were applied for machining precise micro holes and micro channel using electrochemical micromachining (EMM).