纯铝在一种新型碱性电解液中的腐蚀和阳极行为

通过集气、动电位极化曲线、恒流放电、扫描电镜和X射线能谱等方法研究了纯铝在含有锡酸钠的4 mol·L-1氢氧化钾的甲醇-水(甲醇和水的体积比为4:1, 下同)混合溶液中的腐蚀和阳极溶解行为. 实验结果表明, 锡酸钠的添加通过具有较高析氢过电位的金属锡在电极表面的沉积, 极大地抑制了铝在4 mol·L-1氢氧化钾的甲醇鄄水溶液中的腐蚀;而由于在锡沉积层中裂纹的出现, 导致较大浓度锡酸钠的缓蚀作用有所降低. 恒流放电结果表明, 铝在含有锡酸钠的4 mol·L-1氢氧化钾的甲醇鄄水溶液中的恒流放电性能明显改进, 而且铝阳极的放电性能随着锡酸钠含量的增大而逐渐提高. 在20 mA·cm-2的放电电流密度下, 铝阳极在含有10.0 mmol·L-1锡酸钠的电解液中显示了电位相对较低且较平坦的放电平台.     

碱土金属离子与EDTA对纯铝在碱性溶液中的协同缓蚀作用

通过集气实验、极化曲线和电化学阻抗谱等方法研究了碱土金属离子与乙二胺四乙酸(EDTA)对纯铝在4 mol•L-1 KOH溶液中的协同缓蚀作用. 实验结果表明铝在含0.02 mol•L-1 EDTA和饱和Ca(OH)2、Sr(OH)2的溶液中具有最小的腐蚀速率. EDAX分析表明碱土金属离子和EDTA没有参与到铝表面氧化膜的组成中, 说明缓蚀剂是通过吸附在铝表面起作用的, 这表明它们是界面型缓蚀剂而非相间型缓蚀剂.     

纯铝在KOH-乙醇溶液中的电化学行为

研究纯铝在KOH 乙醇溶液中的电化学行为,腐蚀失重、极化曲线、EIS和恒电流放电实验表明,该体系纯铝的腐蚀速率极小,因而有可能应用于密闭电池,并可在相当宽的电位范围内保持一定的活性.放电的终止可能是由于放电产物在电极表面堆积引起的.     

纯铝在强碱溶液中阳极溶解的电化学阻抗谱解析

依据曹楚南提出的法拉第导纳表达式，拟合了纯铝在强碱溶液中的阳极溶解过程的电化学阻抗谱，并据此提出了这一反应进行的机理.结果表明,阻抗谱中的低频容抗弧是由表面裸露的Al转变为中间产物Al(OH)ads的反应引起的，而中频感抗弧则由Al(OH)ads转变为Al(OH)3,ads的反应引起.法拉第导纳的时间常数τ1和τ2的物理意义是物种Al(ss)和Al(OH)ads在单位表面活性位上的转化时间. τ1 >0和τ2 >0是符合稳定性条件的，也能够满足Kramers-Kronig转化的必要条件. g1和g2是与物种Al(ss)和Al(OH)ads在电极表面的覆盖密度随电位E变化有关的参数，由g1< 0可知随电位升高，纯铝表面的活性位面积减小.     

镁在人体模拟液中的腐蚀行为

探索了镁在人工人体模拟Hank溶液中的腐蚀行为, 发现镁在模拟液中的极化行为与在一般NaCl水溶液中相似. 电化学阻抗谱测试结果表明, 镁在模拟液中的一些具体反应对腐蚀的贡献可能比在NaCl溶液中的小. 在模拟液中, 镁腐蚀速度随时间不断变快. 这可能与模拟液中可抑制腐蚀的离子的消耗有关. 镁腐蚀产生了大量的氢气, 并使模拟液碱化. 这些结果表明, 镁虽然极有希望用作可消溶吸收的人体植入材料, 但仍有一些困难需要克服, 解决这些困难的关键在于适当地控制其腐蚀速度.     

Corrosion Behavior of Aluminum in Non‐Uniform Electric Fields

The present paper discusses the effect of the geometrical structure of the electric fieldon the corrosion of aluminum cathodes by electrolysis of aqueous solutions of sodium chloride. A correlation between the mass of the aluminum dissolved from the cathode and the factors electric current density, distance between the electrodes, electrolysis time and sodium chloride concentration by electrolysis with direct current in electric fields of various geometries was found.     

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry by Means of a Lead Mediator

Anodic stripping voltammetry (ASV) is an analysis technique that permits the selective and quantitative analysis of metal ion species in solution. It is most commonly applied in neutral to acidic electrolyte largely due to inherent metal ion solubility. Bismuth (Bi) is a common film used for ASV due to its good sensitivity, overall stability and insensitivity to O₂. ASV, utilizing a Bi film, along with cadmium (Cd) and lead (Pb) as the plating mediators, has recently been adapted to determine zinc (Zn) concentrations in highly alkaline environments (30 % NaOH or 35 % M KOH). Successful analysis of Zn in alkaline relies on the ability of the hydroxide to form soluble metal anion species, such as Bi(OH)₄⁻ and Zn(OH)₄²⁻. Here, we look to extend this technique to detect and quantify copper (Cu) ions in these highly basic electrolytes. However, in general, the use of ASV to detect and quantify Cu ion concentrations is notoriously difficult as the Cu stripping peak potential overlays with that of Bi from the common Bi film electrode. Here, an ASV method for determining Cu concentration in alkaline solutions is developed utilizing Pb as a deposition mediator. As such, it was found that when analyzing Cu solutions in the presence of Pb, the stripping voltammetry curves present separate and defined Cu stripping peaks. Different analyzes were made to find the best stripping voltammetry performance conditions. As such, an accumulation time of 5 minutes, an accumulation potential of≤−1.45 V vs. Hg/HgO, and a concentration of 35 wt% KOH were determined to be the conditions that presented the best ASV results. Utilizing these conditions, calibration curves in the presence of 5.0 ppm Pb showed the best linear stripping signal correlation with an r‐squared value of 0.991 and a limit of detection (LOD) of 0.67 ppm. These results give way to evaluating Cu concentrations using ASV in aqueous alkaline solutions.     

碳钢在NaHCO_3溶液中的阳极极化行为(英文)

研究碳钢在NaHCO3溶液中的阳极极化行为. 极化曲线测试表明,在 (0. 05 ~1. 0mol/L)NaHCO3浓度范围内,碳钢的阳极极化曲线都显示 2个电流峰和 2个钝化区,当HCO3-浓度低于 0. 1mol/L时,两电流峰相距很近,致使第 1个钝化区不易观察到. 而当HCO3-浓度>0. 1mol/L后,其第 1电流峰峰电流愈加上扬,而第 2电流峰峰电流反而下降. XPS分析表明,在较高电位下碳钢形成的表面膜,其外层主要成分为Fe2O3,而内层组成主要含Fe(Ⅱ)和Fe(Ⅲ)氧化物.     

Factors Affecting the Electrodeposition of Aluminum Metal in an Aluminum Chloride–Urea Electrolyte Solution

Electrodeposition of aluminum metal using an AlCl₃–urea ionic liquid electrolyte at room temperature is studied. The molar ratio of AlCl₃/urea, addition of toluene, stirring speed, deposition duration, and temperature are the major factors that affect the deposition of aluminum. The electroplating is carried out at temperatures in the range 20–60°C at a stirring speed 0–80 rpm using bias of 1 V applied for 2 h. The aluminum electrodeposition is enhanced at a high molar ratio of AlCl₃/urea using 20% diluted toluene electrolyte. The microstructure of the deposited aluminum layer is examined using X‐ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The current density is found to decrease with the duration and at lower temperatures. In this study, a current efficiency as high as ~89.98% could be obtained at 60°C.     

吸附伏安法测定纯铝中痕量钛

在盐酸溶液中，钛（Ⅳ）与钽试剂（BPHA）络合物在－0．3V（vs．SCE）或开路情况下吸附于玻璃碳电极表面，在－0．3－－0．8V范围内以250mV.s^-1进行扫描溶出，峰电位为－0．57V，钛（Ⅳ）浓度在1－35ng.ml^-1(-0.3V)下富集2min和0.06-2ng.ml^-1（开路富集4min）范围内与峰电流呈良好的线性关系，体系选择好，灵敏度高，操作简单，用于纯铝中痕量钛的测定，重现性好，结果准确。     

Pitting Corrosion Mechanisms and Characteristics of Aluminum in Solar Heating Systems

The complex characteristics and mechanisms of aluminum pitting corrosion in a solar heating system were studied by the chemical immersion method and electrochemical techniques as well as fractal theory. The results showed that pitting corrosion of Al occurred in a tap water environment due to the local enrichment of Cl^? ions. The higher the Cl^? ions concentration, the more negative the critical pitting potential (E_b) of Al. A linear relationship between E_b and the logarithm of Cl^? ions concentration was observed. The pitting corrosion mechanism of Al in neutral water was explained in terms of complexation corrosion theory. The corrosion surface images of aluminum immersed in tap water were captured and analyzed by image processing technique and box‐dimension method. The fractal characteristics of pit distribution, described by fractal dimension, have been identified. The fractal dimension of the pit distribution increased with the increase of immersion time and had the same trend as that of the weight loss. Fractal dimension can, thus, be used as an important parameter for quantitative evaluation of pitting corrosion of aluminum.     

Corrosion inhibition of aluminum in 1 M H3PO4 solutions by ethanolamines

The inhibitive effect of the investigated compounds (ethanolamine (I), diethanolamine (II) and triethanolamine (III)) on the corrosion behavior of aluminum in 1 M H₃PO₄ solution using weight loss, galvanostatic polarization and quantum chemical calculation methods was studied. The inhibition efficiency was found to depend on type and concentration of the additives and also on temperature. The effect of addition of halide ions to various concentrations of these compounds has also been studied. The apparent activation energy (E_a) and other thermodynamic parameters for the corrosion process have also been calculated and discussed. The galvanostatic polarization data indicated that these inhibitors were of mixed-type. The slopes of the cathodic and anodic Tafel lines (β_c and β_a) are approximately constant and independent of the inhibitor concentration. The adsorption of these compounds on aluminum surface has been found to obey the Freundlich adsorption isotherm. Some quantum chemical parameters and Mulliken charge densities for investigated compounds were calculated by the AM1 semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process. The theoretical results are then compared with experimental data.     

硫酸根离子对铁在弱碱性溶液中阳极溶解和钝化行为的影响

采用浸泡实验, 电化学测试和表面分析技术研究了硫酸根离子浓度对铁在稀碳酸氢钠溶液中开路状态和阳极极化行为的影响. 在无硫酸根离子及含有少量硫酸根离子的碳酸氢钠溶液中, 铁的开路电位约为(-0.225±0.005) V, 并呈现钝化状态, 其电化学阻抗很大, 腐蚀速率较低. 在含有较高浓度硫酸根离子的碳酸氢钠溶液中, 铁的开路电位为(-0.790±0.010) V并呈现活性溶解状态, 其电化学阻抗较小, 腐蚀速率较高, 同时阳极极化曲线上能观察到活化-钝化转变现象. 由于铁在含有较高浓度硫酸根离子的碳酸氢钠溶液中处于活化状态, 阳极极化曲线上存在数个电流峰. 足够高的硫酸根离子浓度会导致铁表面预先形成或转变而成的氧化膜失效. 相比于自然曝氧状态, 在除氧条件下较低的硫酸根离子浓度即可引起铁在碳酸氢钠溶液中由钝态向活性溶解态的转变.     

铝与碱溶液反应的实验研究

铝与氢氧化钠溶液反应一直以来都是教学的难点,从定量角度证明了该反应的氧化剂,并解释了氢氧根离子在反应中的作用。在此基础上,结合实验表现出的铝与不同碱溶液反应的差异,进一步探讨了几种阳离子对铝与碱溶液反应的影响。     

Effects of High Salt Concentration and Residue on Copper and Aluminum Corrosion

Traditional researches on metal corrosion under salt solutions deposit conditions are usually carried out by visual, electron microscopic observations and simple electrochemical measurement via a traditional one-piece electrode. These techniques have difficulties in measuring localized corrosion that frequently occur in inhomogeneous media. This paper reports the results from the experiments using specially shaped coupons and a relatively new method of measuring heterogeneous electrochemical processes, namely, the wire beam electrode(WBE). Preliminary results from copper and aluminum corrosion in highly concentrated sodium chloride solutions with and without solid deposits show that the method is useful in simulating and studying corrosion especially localized corrosion in pipelines.     

Indirect Voltammetric Determination of Aluminum in Environmental and Biological Samples in the Presence of the Aluminum Chelating Drugs

A simple indirect method using aluminum chelating drugs as electroactive complexation ligands for the voltammetric determination of aluminum in environmental and biological samples on glassy carbon working electrode is studied. In the range of pH 8–9, desferrioxamine (DFO), 1,2‐dimethy‐3‐hydroxypyrid‐4‐one (Hdmp), 3‐hydroxy‐2‐methyl‐4H‐pyran‐4‐one (Hma) and 2,3‐dihydroxypyridine (DHP) yielded good anodic peaks. It was demonstrated that the decrease of the anodic peak current of the drugs was linear with the increase of aluminum concentration. Among them, Hdmp was found the best complexible ligand and chosen for the voltammetric determination of aluminum with EDTA as chelant, which was used for masking most of the interferences. Under the optimum experimental conditions, the linear range for determination of Al by Hdmp was 5×10^?7–3×10^?5 mol L^?1 Al(III), the detection limit was 2×10^?7 mol L^?1, and the relative standard deviation for 3×10^?6 mol L^?1 Al(III) was 2.6% (n=7). The proposed method was applied to the determination of Al in real water samples and biological samples. The Al concentration in serum samples can be measured directly without time‐consuming digestion pretreatment.     

镁铝原电池数字化实验的意外——再探铝与碱性溶液的反应

用电压传感器测得使用铝、镁作电极,氢氧化钠溶液或氨水作电解质的原电池,在放电过程中存在电极极性翻转现象,说明铝片不仅能与强碱反应,也能与氨水反应。该结论和铝片和氨水反应的试管实验的结果一致。换用碳酸钠溶液作电解质的原电池不存在电极极性翻转现象;结合试管实验中铝片与碳酸钠溶液反应的产物分析,发现有难溶于水的碱式碳酸钠铝生成,推测其覆盖在铝片表面,避免了电极极性翻转。     

铝壶煮沸的饮用水中铝的形态分析

用过滤、离子交换和光解氧化分离自来水和经铝壶煮沸的饮用水中铝的形态,以石墨炉原子吸收光谱法测定铝的浓度,采用化学平衡模式计算铝的形态分布。实验结果表明：经铝壶煮沸１ｍｉｎ的饮用水中颗凿态铝量比自来水降低了３．３倍,可交换态、不可交换有机态、不可交换无机态铝量分别２增加了１．４、０．５和１．２８倍,可交换态和不可交换无机态是铝的主要存在形态。随着煮沸时间的增加,可交换态、不可交换有机态、不可交换无机     

化学/电化学腐蚀法快速制备超疏水金属铝

提出一种金属铝超疏水表面的快速制作方法. 先以化学腐蚀在铝表面形成微米级粗糙结构, 再通过电化学腐蚀构筑纳米结构, 在20 min内完成了超疏水表面所需粗糙结构的制备. 这种化学腐蚀/电化学腐蚀两步法比单独化学或电化学腐蚀方法在时间上缩短了1~2个数量级, 且不受铝材晶形限制, 同时电化学腐蚀所用电流密度也降低了1个数量级, 降低了对电源设备的要求, 可望大规模应用于工业生产和其它金属的超疏水表面制备.     

海水环境中典型阴离子对5083铝合金腐蚀行为的影响

采用析因分析试验及动电位极化曲线、电化学阻抗谱(EIS)等测试方法,研究了海水环境因素中的典型阴离子（Cl^-、HCO₃^-、SO₄^2-交互作用对5083铝合金耐蚀性的影响. 结果表明,三种阴离子中,Cl^-、HCO₃^-对铝合金点蚀起促进作用. Cl-与HCO₃^-交互作用时,在Cl^-浓度一定的情况下,随着HCO₃^-浓度的增加,5083铝合金耐蚀性呈现出上升→下降→再上升的趋势,在70～90mg•L^-1时耐蚀性能明显降低;在HCO₃^-浓度一定的情况下,Cl^-浓度较低时5083铝合金耐蚀性比Cl^-浓度较高时差. 在Cl^-、HCO₃^-浓度较低情况下,SO₄^2-具有抑制腐蚀的作用;当Cl^-、HCO₃^-浓度较高时,SO₄^2-抑制腐蚀的作用不明显.