磁电解法处理工业废水过程中的电极行为

从提高电解处理的效率、降低能耗和改善回收沉积物性状的目标出发，通过对含铜工业废水的磁电解处理试验和极化曲线的测定，研究了外加磁场对电解电极过程的影响。结果表明，磁电解技术可使工业废水电解处理的许用电流密度提高１倍多，在本试验电流密度下过电位降低５０％以上，从而使槽电压和能耗降低，并可获得性状优良的回收沉积物。

海洋钢筋混凝土结构牺牲阳极保护系统电极行为的研究

于1989－1990年在室内条件下，用牺牲阳极保护浸泡于海水中的多种钢筋混凝土试件，测试不同试件中钢筋极化与阳极布局、涂层质量、涂层厚度及试件浸水情况的关系。结果表明。牺牲阳极能有效地保护全浸海水中的混凝土试件，对间断浸淋海水的试件也有一定的保护作用。通过改善阳极安装工艺，保护作用可望提高；电偶电流在各阴阳极上的分布将随涂层质量、涂层厚度和试件浸水情况不同而异；回路中电阻和电极极化情况是影响电流分布的主要因素。

电解法合成二茂铁各组分电极行为的研究

用线性扫描电位法测定了以0.1M溴化钠为支持电解质、N,N-二甲基甲酰胺(DMF)为溶剂的体系中,电解合成二茂铁的阳极和阴极极化曲线,讨论了各组分的电极行为.

电凝聚法处理印染废水过程中铁电极行为的研究

本文对以铁为电极进行电凝聚处理印染废水时pH值对铁电极行为的影响进行了研究。测出在恒电流条件下电解电压,阴极电位和阳极电位随PH值的变化曲线以及不同pH值条件下恒电位极化曲线。据此研究了电解时电极反应和应控制的pH条件。

乙腈-水相1,4-二氯苯在铂电极上的电氧化行为

The mechanism and characteristics of electrochemical oxidation of 1,4-dichlorobenzen in simulated wastewater were investigated on a platinum electrode.The cyclic voltammetric profiles showed that the oxidation peak potential and current density increased with the increase of the concentration of 1,4-dichlorobenzene,nevertheless,the oxidation potential of 1,4-dichlorobenzene in acetonitrile-aqueous solution was smaller than that in acetonitrile solution.Chronoamperometric experimental results suggested that the 1,4-dichlorobenzene degradation included both direct electro-oxidation of 1,4-dichlorobenzene by loss of electrons and indirect oxidation with anodically formed free radicals.Additionally,parachlorophenol,1,4-benzoquinone,maleic acid,oxalic acid,acetic acid,and formic acid were identified as main electro-oxidation products by ion chromatography or high performance liquid chromatography.Moreover,a yellow polymer film,which influenced the electrochemical oxidation process,was clearly identified as a rough surface after electrochemical reaction in comparison to a smooth and glossy surface of platinum electrodes without polymer film as observed from SEM image.

4A沸石/离子液体修饰碳糊电极的电化学行为及其对多巴胺的测定

以4A沸石和1-正丁基-3-甲基咪唑六氟磷酸盐离子液体为修饰剂,制备了沸石/离子液体修饰碳糊电极,研究了该电极的电化学行为及其对多巴胺的选择性测定。实验表明:该修饰电极在铁氰化钾溶液中有一对明显的氧化还原峰,而且可逆性较好。在沸石/离子液体修饰电极上,抗坏血酸和多巴胺的峰电位差大约为225 mV;在抗坏血酸存在下,多巴胺的峰电流与浓度在5.0×10-8 mol·L-1到9.0×10-6 mol·L-1的范围内呈现良好的线性关系,检出限为4.9×10-9 mol·L-1(S/N=3)。该电极具有高灵敏性和稳定性,可用于多巴胺的检测。

含稀土的镍基合金的析氢电催化行为

用电沉积方法制备的Ni Ce P和Ni La P合金作阴极测得析氢阴极极化曲线 ,结果表明 ,合金电极上析氢速率比Ni电极上约大 10倍 ,析氢电势正移 >2 0 0mV ,显示出含稀土的镍基合金具有较高的析氢电催化活性。

氯化镁电解过程中碱金属的行为

研究了氯化钠、氯化钠－氯化钾、氯化镁－氯化钠－氯化钾熔体系中碱金属的析出行为．研究表明：由于去极化作用．碱金属析出电位远正于其热力学析出电位．

电极结构对滑动弧放电等离子体尺寸的影响规律

为得到电极结构(电极长度和电极张角)对滑动弧放电等离子体尺寸大小的影响规律,设计并制作了一套易于更换电极、调整电极间距的滑动弧等离子体发生装置。利用示波器对滑动弧放电等离子体的电信号进行测量,结合高速摄影仪和DV相机对滑动弧放电图像进行了记录与分析。试验结果表明:随着气体流量的增加,滑动弧放电呈现3种状态;稳定的滑动弧放电等离子体的电压波形是一种周期性的电压峰值逐渐增大的波形,它反映了电弧的产生、移动和熄灭。利用流量计控制气体体积流量为10 L/min,在张角为30°的情况下,等离子体长度随电极长度的增加而逐渐减小,并且在电极长度达到50 mm时,等离子体已无法超出电极末端。等离子体宽度是在电极长度为20 mm时达到最大。保持电极长度为20 mm,改变电极张角,发现张角越大,电弧沿电极的滑动距离越小,电极引导电弧滑动的作用无法得到充分发挥,导致滑动弧放电等离子体的尺寸减小。

Electrochemical corrosion behavior of arc sprayed Al-Zn-Si-RE coatings on mild steel in 3.5% NaCl solution

Al-Zn-Si-RE coating with high Al content was deposited on mild steel by arc spraying. The electrochemical behavior of Al-Zn-Si-RE coating in 3.5%NaCl solution was systematically studied by potentiodynamic polarization, corrosion potential (φcor ) and electrochemical impedance spectroscopy techniques (EIS). The impedance data were fitted to appropriate equivalent circuits to explain the different electrochemical processes occurring at the electrode-electrolyte interface. The results indicate that Al-Zn-Si-RE coating reveals the similar polarization behavior as Zn-15Al coating. The coating has no passive region in the anodic polarization, but far lower corrosion current and much higher corrosion potential. Al-Zn-Si-RE coating provides effective sacrificial protection for steel substrate and the sacrificial anodic protection plays dominant role during the immersion process. In addition, theφcor evolution and EIS plots indicate that the corrosion process can be divided into five stages: pitting-dissolution-redeposition, activation corrosion, cathodic protection, physical barriers and the coating failure.

Electrochemical behavior of Pb-Ag-Nd alloy during pulse current polarization in H_2SO_4 solution

The anodic layer and oxygen evolution behavior of Pb-Ag-Nd alloy during pulse current polarization and constant current polarization in 160 g/L H2SO4 solution was comparatively investigated by chronopotentiometry, SEM, XRD, EIS and Tafel techniques. The results show that the anodic layer on Pb-Ag-Nd alloy formed through pulse current polarization is more intact and presents fewer micro-holes than that formed through constant current polarization. This could be attributed to the low current density period, which works as a ‘recovery period＇. During this period, the oxygen evolution reaction is less intense, which benefits the recovery of porous anodic layer. Pb-Ag-Nd anode also shows a lower anodic potential during pulse current polarization, which is in accordance with its smaller charge transfer resistance and smaller Tafel slope coefficient at high over-potential region. The lower anodic potential could be ascribed to the higher concentration of Pb O2 in the anodic layer, which promotes the formation of more reactive sites for the oxygen evolution reaction.

Effects of gallium on electrochemical discharge behavior of Al-Mg-Sn-In alloy anode for air cell or water-activated cell

In order to evaluate the electrochemical properties of aluminum alloy anode under high current densities in alkaline electrolyte, the galvanostatic discharge, potentiodynamic polarization and hydrogen evolution tests of three experimental Al?Mg?Sn?In?(Ga) alloys were performed. The results show that the alloying element gallium improves the working potentials of experimental Al?Mg?Sn?In alloys under different discharge current densities. The average working potentials of the alloys containing gallium can reach?1.3 V under current density ranging from 650 to 900 mA/cm2, while those of alloy without Ga are only?1.0 V. Such phenomenon is attributed to the solid solution which can form amalgam with aluminum matrix. Such an amalgam can form the hydrolyzed species during the discharge process and lead to the corrosion infiltrating into aluminum matrix.

Effect of MnO_4^- and silver content on electrochemical behaviour of Pb-Ag alloy anodes during potential decay periods

The effect of MnO4- and silver content on electrochemical behaviour of five commercial Pb-Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO4- ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO4- ions, the Pb-0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO4 ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO4-, the anode Pb-0.72%Ag had the best corrosion resistance, followed by anodes Pb-0.67%Ag, Pb-0.60%Ag, then the close anodes Pb-0.58%Ag and Pb-0.29%Ag-0.1%Ca by the electrochemical impedance spectroscopy （EIS） analysis.

电化学石英晶体微天平研究普鲁士蓝薄膜的两电极系统伏安行为

采用双通道电化学石英晶体微天平(EQCM)研究了水溶液中普鲁士蓝(PB)薄膜修饰的两金电极上的两电极循环伏安(CV)电化学行为,归属了普鲁士白、PB、普鲁士黄三者间的转变过程,以及金基底和PB膜内所夹带的Fe(CN)63-/Fe(CN)64-杂质的氧化还原峰,为UV-Vis光谱电化学实验所支持.夹在两喷金的铟锡氧化物(ITO)电极间的PB粉末的两电极固态CV图和两PB修饰金电极在水溶液中的两电极CV图相似,说明发生了类似的电极反应.双通道EQCM有望成为研究其他物质或材料的两电极系统电化学行为的高效技术.

酸度对Cr(Ⅲ)离子存在形态的研究

一、前言在《无机化学》教材中,我们讲到,Cr（Ⅲ）离子在水溶液中是以六水合铬（Ⅲ）离子[Cr（H2O）)6]3+存在.其实Cr（Ⅲ）离子在水溶液中的存在形式非常复杂,随溶液酸度的不同,其存在形态变化很大.本文用示波极活法研究了Cr（Ⅲ）离子在不同pH条件下的电极行为及其存在形态,并根据水解平衡计算的结果进一步对酸度对Cr（Ⅲ）离子存在形态的影响进行了讨论.

Electrochemical corrosion of Sn-0.75Cu solder joints in NaCl solution

The corrosion behaviors of Sn-0.75Cu solder and Sn-0.75Cu/Cu joint in 3.5% NaCl（mass fraction） solution were studied by potentiodynamic polarization test and leaching measurement.The polarization curves indicated that the corrosion rate of Sn-0.75Cu solder was lower than that of Sn-0.75Cu/Cu joint.The morphology observation and phase composition analysis on the corroded product at each interesting potential suggested that Sn3O（OH）2Cl2 formed on the surface of Sn-0.75Cu solder at active dissolution stage.As the potential increased from active/passive transition stage,all the surface of Sn-0.75Cu solder was covered by the Sn3O（OH）2Cl2 and some pits appeared after the polarization test.Compared to the Sn-0.75Cu solder alloy,much more Sn3O（OH）2Cl2 formed at active dissolution stage and the pits with bigger size were observed after polarization test for the Sn-0.75Cu/Cu solder joints.The leaching test confirmed that the faster electrochemical corrosion rate resulted in the larger amount of Sn released from the Sn-0.75Cu/Cu solder joints.

Electrochemical behavior of graphite anode during anode effect in cryolite molten salts

Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.

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.

Oxygen Evolution Behavior of PTFE-F-PbO2 Electrode in H2SO4 Solution

F-PbO2 electrode and polytetrafluoroethylene （PTFE） doped F-PbO2 electrode （PTFE-F-PbO2） were prepared on a plexiglas sheet substrate by a series of procedure including chemical and electrochemical depositions. The electrochemical activities of these two electrodes for oxygen evolution （OE） reaction were examined by electrochemical tests. In comparison with F-PbO2, PTFE-F-PbO2 electrode exhibited larger active surface area and higher oxygen vacancy deficiency, which resulted in its higher electrocatalytic activity for OE. In addition, both exchange current density and activation energy of the electrodes for OE were calculated in terms of active surface area. The values of exchange current density and activation energy in 0.5 mol·L^-1 H2SO4 aqueous solution were 1.125×10^ -3 mA·cm^-2 and 18.62 kJ·mol^-1 for PTFE-F-PbO2, and 8.384×10^-4 mA·cm^- 2 and 28.98 kJ·mol^-1 for F-PbO2, respectively. Because these values are calculated on the basis of the active surface areas of the electrodes, the enhanced activity of PTFE-F-PbO2 can be attributed to an increase in oxygen vacancy deficiency of PbO2 due to doping by PTFE. The influence of PTFE adulteration on the activity of PbO2 film electrode for OE was investigated in detail in this study.

Corrosion behavior of 2024 Al-Cu-Mg alloy of various tempers

Corrosion behavior of 2024 Al-Cu-Mg alloy of different tempers was assessed by potentiodynamic polarization studies in 3.5% NaCl solution, 3.5% NaCI＋I.0% H2O2 solution and 3.5% NaCl solution at pH 12. Polarization curves showed shifting of corrosion potential （φPcor） towards more negative potential with increasing ageing time and shifting of φcorr in the positive direction with the addition of H2O2 in NaCl solution. Polarization curves in 3.5% NaCl solution at pH 12 exhibited distinct passivity phenomenon. Optical micrographs of the corroded surfaces showed general corrosion, extensive pitting and intergranular corrosion as well. Cyclic potentiodynamic polarization curves exhibited wide hysteresis loop and the mode of corrosion attack confirmed that the alloy states are susceptible to pit growth damage. Attempts were made to explain the observed corrosion behavior of the alloy of various tempers in different electrolytes with the help of microstructural features.