Cu/Ti在模拟海水中的电偶腐蚀行为(英文)

采用电化学阻抗谱、电化学噪声和扫描电镜等技术研究了纯铜、铜/钛耦合电极在模拟海水中的腐蚀行为。结果表明:纯铜的腐蚀过程分2个阶段,其腐蚀阻抗和点蚀参数SE均遵循先增后降的规律,而其腐蚀参数SG的变化规律则正好相反;铜/钛耦合电极的腐蚀过程则由3个阶段组成,其腐蚀阻抗和点蚀参数SE均遵循先降后升到最后再降的规律,而其腐蚀参数SG则同样反向变化。铜和钛之间的电势差加速了纯铜的点蚀萌生,同时铜/钛耦合电极的腐蚀电位总是正于纯铜的腐蚀电位。     

Anode characteristics of Al/Ti galvanic couple in a salt spray environment

The galvanic corrosion behavior of a 2A12 aluminum alloy and a Ti‐15‐3 titanium alloy in a salt spray environment was investigated. The results indicated that the galvanic effect accelerated the dissolution rate of the anodes significantly; however, the corrosion of the anode was not uniform. The region adjacent to the coupled joint experienced the most significant corrosion, with galvanic corrosive action emerging as dominant. The corrosion of the region distant from the joint was slight and was dominated by the self‐corrosion process. A new model for the current difference distribution of the galvanic couple was established to illuminate the nonuniform corrosion phenomenon of the anode.     

Electrochemical oxidation of sodium sulfide on rotating ring-disc electrode

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Electrochemical investigation on hydride electrode with tungsten carbide additive

1　ＩＮＴＲＯＤＵＣＴＩＯＮＧｅｎｅｒａｌｌｙ,ｉｎｔｈｅｃｈａｒｇｅ (ｃａｔｈｏｄｉｃ) ｐｒｏｃｅｓｓｏｆｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｅｌｅｃｔｒｏｄｅｓ,ｔｈｅｅｌｅｃｔｒｏｌｙｓｉｓｏｆｗａｔｅｒｔａｋｅｓｐｌａｃｅａｎｄｔｈｅａｔｏｍｉｃｈｙｄｒｏｇｅｎｆｉｒｓｔａｄ ｓｏｒｂｓｏｎｔｈｅｓｕｒｆａｃｅｏｆｅｌｅｃｔｒｏｄｅａｃｃｏｒｄｉｎｇｔｏｒｅａｃｔｉｏｎ(1 )ａｔｔｈｅｐｏｔｅｎｔｉａｌｏｆ -0 .82 8ＶｖｓＨｇ/ＨｇＯ .Ａｓｔｈｅｃａｔｈｏｄｉｃｐｏｔｅｎｔｉａｌ (ａｂｓｏｌ…     

Galvanic Corrosion Behavior of Copper-Drawn Steel for Grounding Grids in the Acidic Red Soil Simulated Solution

The influence of pH and metallographic structure on the corrosion behavior of copper-drawn steel is studied with the simulated system. The effect of pH on the corrosion behavior of copper-drawn steel has been investigated using open-circuit potential, potentiodynamic polarization, galvanic current measurement, scanning electron microscopy and scanning vibrating electrode technique techniques. The steel is corroded as anode, while the corrosion of copper plate is protected as cathode. All the results revealed that pH and metallographic structure had a significant influence on the corrosion behavior of copper-drawn steel. With the decrease in pH value from 6 to 2.4, the corrosion rate of copper-drawn steel galvanic couple (Cu-Fe GC) obviously increased in the simulated solution of acidic red soil. The electric field formed by the Cu-Fe GC changes the direction of ion migration between the copper and drawn steel electrodes, which impacts the composition and microstructure of corrosion products formed on the electrode surface.     

Electrochemical discharging performance of 3D porous magnesium electrode in organic electrolyte

A novel type of porous magnesium electrode with a stable 3D copper foam as current collectors for the organic magnesium-air battery was prepared by both amperostatic and pulsed electrodeposition of magnesium on copper foam substrates in an electrolyte of 1 mol/L EtMgBr/THF solution, respectively. Optimal parameters of the pulsed electrodeposition were obtained using a bending cathode at the right angle. The surface morphology of the porous electrode was investigated by SEM, and the discharging performance of the porous magnesium electrode was detected by the chronoamperometric measurement. The electrochemical stability of 3D copper foam current collectors was examined by cyclic voltammetry, SEM and ICP-OES analyses. The results show that the rate capability of the porous magnesium electrode with a stable 3D copper foam as a current collector is better than that of the planar magnesium electrode, and the rate capability of the porous magnesium electrode prepared by the pulsed electrodeposition is superior to that of the porous magnesium electrode prepared by the amperostatic electrodeposition. The 3D structure of copper foam current collectors of the porous magnesium electrode could keep stable during the discharging process.     

The diffusion couple technique in phase diagram determination

The diffusion couple technique is a valuable experimental approach in studying phase relations in multicomponent systems. The use of different modifications of the method is illustrated by examples of phase diagram determination in various ternary systems. It is also shown that a number of error sources may appear when multiphase diffusion experiments are employed for constructing isothermal cross-sections. The difficulties connected with the concentration measurement at the interfaces and problems associated with the formation of a quasi-equilibrated diffusion zone are discussed. It is demonstrated that the efficiency of the diffusion couple technique is very high. However, in order to increase the reliability of the information obtained about a ternary diagram, a combination of the diffusion methods with an investigation of selected alloys is desirable.     

不同电极电火花加工硬质合金的效率研究

通过实验的方式对采用不同电极电火花加工技术加工硬质合金的效率进行了研究。通过调整加工过程中的脉冲宽度和开路电压，变换加工电极，探讨了不同电极材料、开路电压及脉宽加工硬质合金的加工效率的影响.     

船用尾轴腐蚀开裂分析

某船用尾轴局部区段发生凹槽状损伤,采用扫描电镜、金相显微镜等设备对损伤尾轴的化学成分、微观组织及断口形貌进行了分析,结果表明,该尾轴在服役过程中由于没有隔绝液态介质,从而导致电偶腐蚀而开裂。     

Metal transfer characteristics of GMAW with strip electrode

Abstract

The metal transfer process of gas metal arc welding with strip electrode is observed by a high speed digital camera system. Because the rectangular strip electrode has a large width/thickness ratio, the pendant droplet is elliptical in shape, and multicurrent channels are generated. The Lorentz force induced between the multicurrent channels drives the droplet and welding arc to move along the strip electrode end, but the droplet always lags behind the welding arc. The movement results in uncertain droplet’s detaching location and transition trajectory. The projected transfer mode is promoted, and the streaming and rotating transfer modes are restrained. With the increase in welding power, the droplet motion is faster but more stable. The stability can be reflected from the fluctuation of the welding current and arc voltage waveforms.     

Determination of phase diagrams using the diffusion couple technique

1. Introduction It is commonly recognized that phase diagrams act as important guidelines in the development and production of new materials. The experimental de- termination of the phase diagrams is generally very time-consuming, especially for complex systems. As a summary on our previous work dedicated to measurement of phase diagrams, the present paper will demonstrate that flexible combination of the diffusion couple technique with equilibrated alloys is powerful and efficient in the dete…     

Electrochemical characteristics of dodecylbenzene sulfonic acid-doped polyaniline in aqueous solutions

The electrochemical characteristics of the polyaniline (PAn) films doped with dodecylbenzene sulfonic acid (DBSA) were investigated in aqueous solutions by means of cyclic voltammetry. The PAn-DBSAs film showed a good electrochemical activity in a weak acid solution as well as in a strong acid solution due to the incorporation of small cation instead of DBSA trapped in the film for charge neutralization of polymer matrix.     

Electrochemical study of the surface metal matrix composite developed on AA 2024-T351 by the friction stir process

ABSTRACT

This work is focused on the evaluation of the corrosion behaviour of an AA2024-T351/SiC surface composite produced by friction stir processing (FSP). The surfaces composite show a quite homogenous distribution of the SiC particles in the stir zone, together with a significant grain size reduction as Electron Backscatter Diffraction analysis confirms. The corrosion behaviour was evaluated in 3.5 wt-% NaCl solution using electrochemical techniques. The complete study shows that all processed samples have similar corrosion resistance at the stirred region and differ from the base material behaviour. The results indicate that the galvanic coupling metal matrix–SiC particles are less active than the galvanic coupling metal matrix–Cu-rich second phases. Although the initial corrosion resistance of the base aluminium alloy is the worst of all systems studied, for long immersion times the development of corrosion through grain boundaries was found to progressdeeper in the 2024Al/SiC surface produced by FSP.     

不同控制模式下漆包线电极头的烧损规律

以试验为基础,深入分析了漆包线电极头在不同控制模式下电极烧损的基本规律和特点。通过数据采集系统实时获取点焊过程电参数信息,结合电极头焊接过程中的物理现象,对过程信息进行特征提取对比分析。试验结果表明,连续焊接过程中,控制模式对电极头的寿命和烧损过程影响较大,电极头电阻变化与电极烧损过程具有明显的对应关系。电阻曲线的拐点时间反映出电极头进入不同烧损阶段。电极头电阻值的改变会导致产热量的变化,使得不同控制模式电极头烧损速度差异较大。     

GALVANIC INTERACTION OF CONTACTING SULFIDE PARTICLE AND ITS EFFECT ON FLOTATION

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交流电阻点焊中电极位移波动特征的分析

利用改进的交流电阻点焊监控系统采集电极位移和焊接电流,经分析认为电极位移曲线上的波动是由50 Hz的交流电阻热脉冲引起的.利用电阻点焊中的洋葱环现象分析了电极位移波动特征的机理,认识到电极位移在熔核形成前以热膨胀为主,在熔核形成后以相变膨胀为主,并且都具有波动特征.利用焊接电流曲线提供的晶闸管触发角和导通角依次计算功率因数角、动态电阻和动态电阻热.通过位移波动周波峰值与动态电阻热的对比分析,发现位移波动周波峰值在点焊过程中对热膨胀与相变膨胀有较强的敏感性,能用来反应熔核形成过程的不同阶段.     

Electrochemical characteristics of iron in acidic solutions containing some organic sulphur compounds

Corrosion inhibition of bis-n-butyl-sulphinylmethane, bis-n-butyl-sulphonylmethane and ethylene oxide condensates of 2,2′-dihydroxy-n-hexylsulphide on iron in sulphuric and hydrochloric acids was measured by using electrochemical methods. These compounds were excellent inhibitors for acidic corrosion of iron and inhibited the cathodic and the anodic corrosion reactions.