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。     

Electrochemical oxidation of sodium sulfide on rotating ring-disc electrode

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Electrochemical investigation on hydride electrode with tungsten carbide additive

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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.     

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.     

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.     

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.     

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。     

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 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.     

GALVANIC INTERACTION OF CONTACTING SULFIDE PARTICLE AND ITS EFFECT ON FLOTATION

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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.     

伺服焊枪点焊的电极力控制特性及其对电极磨损的影响

为促进伺服焊枪在车身制造中的应用,对比分析电机驱动伺服焊枪(简称"伺服焊枪")与气动焊枪的电极力控制特性。结果表明,伺服焊枪接触工件时电极所受冲击力小,达到预压力时间短,焊接阶段的电极力波动较小,具有更精确的电极力控制能力。在此基础上进行伺服焊枪和气动焊枪点焊的电极磨损实验,进一步分析电极力变化对电极磨损的影响。结果表明,在完全相同的焊接条件下,由于伺服焊枪良好的电极力控制特性,其电极磨损速率较低。在整个电极磨损周期,伺服焊枪点焊镀锌钢板的轴向磨损随着电极力的增加而增加,但在磨损初期阶段,由于飞溅和点蚀的影响,较小电极力下的轴向磨损反而更大一些。     

T2/TC4在静态人造海水中的电偶腐蚀行为

进行T2/TC4电偶对在静态人造海水中的电偶腐蚀实验,通过电化学工作站、原子发射光谱分析仪、扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)研究T2/TC4在静态人造海水中电偶腐蚀时的铜离子释放速率与腐蚀行为。结果表明:当T2/TC4发生电偶腐蚀时反应强烈,T2为电偶对阳极发生加速腐蚀,TC4为电偶对阴极;与T2自腐蚀相比,T2/TC4电偶腐蚀的铜离子释放速率提高了数十倍,可以维持在160μg/(cm^2·d)左右,能达到抑制大多数海洋生物附着的海洋防污要求;T2自腐蚀的腐蚀产物以Cu_2O为主,与TC4电偶腐蚀后的T2试样表面无腐蚀产物覆盖。     

Electrochemical hydrogen absorbing properties of graphite/AB5 alloy composite electrode

Graphite is an inexpensive carbon material, but its hydrogen absorbing performance has attracted little attention. In this paper, in order to lower the cost of nickel metal-hydride (Ni-MH) battery, graphite is used as a hydrogen absorbing material in its negative electrode. The results of charge-discharge tests show that the graphite electrode has poor electrochemical hydrogen absorbing performance. The capacity of the graphite/AB₅ alloy (90 wt%) composite electrode is close to AB₅ alloy (298 mAh/g), but it has higher charge-discharge polarization and difficulty in activation. When graphite is modified with metal nickel powder by a simple ball milling process, the capacity of the composite electrode reaches to 315 mAh/g and its activation is accelerated. The results of electrochemical impedance spectroscopy (EIS) tests show that hydrogen diffusion in the modified composite electrode is more rapid than in AB₅ alloy, thereby resulting in lower charge-discharge polarization and better discharge performance at large currents.     

T2/TC4在静态人造海水中的电偶腐蚀行为研究

进行T2/TC4电偶对在静态人造海水中的电偶腐蚀实验,通过电化学工作站、原子发射光谱分析仪、扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)研究T2/TC4在静态人造海水中电偶腐蚀时的铜离子释放速率与腐蚀行为。结果表明：当T2/TC4发生电偶腐蚀时反应强烈,T2为电偶对阳极发生加速腐蚀,TC4为电偶对阴极;与T2自腐蚀相比,T2/TC4电偶腐蚀的铜离子释放速率提高了数十倍,可以维持在160μg/(cm2.d)左右,能达到抑制大多数海洋生物附着的海洋防污要求;T2自腐蚀的腐蚀产物以Cu2O为主,与TC4电偶腐蚀后的T2试样表面无腐蚀产物覆盖。     

TiB2-ZrB2涂层电极与TiB-ZrB2/Ni涂层电极失效对比分析

采用扫描电镜、能谱分析、X射线衍射仪以及显微硬度等表征手段,分析TiB2-ZrB2涂层与TiB2-ZrB2/Ni涂层电极点焊镀锌钢板时的失效过程.研究发现,无论是ZrB2-TiB2涂层还是ZrB2-TiB2/Ni涂层,在一定程度上均具有阻碍钢板镀层与点焊电极基体产生合金化反应的能力.ZrB2-TiB2、ZrB2-TiB2/Ni涂层电极失效过程存在些许不同,前者由于涂层与基体间结合力差,且涂层内塑性相相对较少,导致在点焊热和力的作用下,涂层逐渐脱落,点焊电极最终在合金化及塑性变形作用下发生失效.后者由于具有一定塑性,且涂层与基体结合力较好,点焊过程中涂层不会出现完全脱落现象.涂层作用一直持续至电极失效,电极失效形式主要表现为塑性变形.     

Electrochemical characteristics of hydrothermally deposited nickel hydroxide on multi-walled carbon nanotube for supercapacitor electrode

Supercapacitor performance of nickel hydroxide powder electrode with different carbon conductor and nickel hydroxide/multi-walled carbon nanotube composite electrode had been studied by cyclic voltammetic method in 6 M KOH solution. Active carbon, Superp, Ketjen Black and multi-walled carbon nanotube were used as carbon conductor in nickel hydroxide powder electrode. It showed that multi-walled carbon nanotube conductor can bring good performance for nickel hydroxide powder supercapacitor electrode. Moreover, nickel hydroxide/multi-walled carbon nanotube composite was fabricated by hydrothermal method, using as supercapacitor electrode. Our findings show that 10 wt% nickel hydroxide loading on multi-walled carbon nanotube has good power performance. The capacitances for 10 wt% nickel hydroxide loading amount at high scan rate 100 and 500 mV/s were 221 and 118 F/g, respectively. Nickel hydroxide evenly loaded onto multi-walled carbon nanotube composite electrode has good conductivity and can contribute more capacitance.