铝箔表面化学镀锌对其在HCl-H 2 SO 4体系中电蚀性能的影响

将高压铝电解电容器用电子铝箔在含Zn2＋的5.0%NaOH溶液中实施化学镀锌处理,然后在HCl＋H2SO4电解液中进行直流电解扩面腐蚀得到腐蚀箔;采用极化曲线研究化学镀锌处理对扩面腐蚀时铝箔点蚀电流、点蚀电位的影响,利用电化学交流阻抗（EIS）研究化学镀锌处理对铝箔电解腐蚀时电化学特征的影响;使用扫描电镜（SEM）观察化学镀锌处理对腐蚀箔表面和横截面形貌的影响;测试100 V形成电压下腐蚀箔的比电容。结果表明：铝箔表面化学镀锌形成的Zn-Al微电偶有助于电蚀时降低点蚀电极反应的阻力,提高点蚀电流密度,增加铝箔表面蚀孔密度和蚀孔分布的均匀性;随着碱液中Zn2＋浓度的提高,腐蚀箔的比电容逐渐增加。     

电解工艺条件对铝箔腐蚀形貌与比电容的影响

利用扫面电镜(SEM)、数字电桥研究了铝电解电容器用高压电子铝箔在硫酸+盐酸体系中进行电化学腐蚀扩面时,工艺条件对铝箔腐蚀形貌与比电容的影响规律:电解腐蚀时间对铝箔腐蚀后形貌与比电容影响较大,发孔时间延长、扩孔时间缩短,隧道孔密度增加、孔直径减小;发孔电流密度对铝箔腐蚀形貌与比电容影响较小,只要高于点蚀电流密度,小电流长时间发孔与大电流短时间发孔都可以在铝箔表面形成足够密度的蚀孔结构;电解液温度对铝箔腐蚀形貌和比电容影响较大,随着发孔液温度的提高,蚀孔密度增加、蚀孔孔径减小,隧道孔长度减小.     

Relationship between Trace Mn and the Pitting Behavior of Aluminum Foil Used for High Voltage Electrolytic Capacitors

研究了微量锰元素添加对高压电解电容器阳极用铝箔的点蚀行为以及腐蚀箔性质的影响。使用二次离子质谱仪分析了轧制及退火铝箔中锰的元素分布。结果表明,锰在铝箔中的深度分布随着锰含量的增加而变化,但退火后铝箔中形成的立方织构的体积分数保持稳定。随锰含量增加,锰在退火铝箔表面的偏聚趋势增强。在相同的加电腐蚀条件下,腐蚀后锰含量高的铝箔表面具有更高密度的方形点蚀孔,并且并孔更少,点蚀孔分布更加均匀。在所研究的范围内(2.3~14.7μg/g),在520 V形成的腐蚀箔的比电容随锰含量的增加而提高。     

微量Mn与高压电解电容器用阳极铝箔的点蚀行为关系（英文）

研究了微量锰元素添加对高压电解电容器阳极用铝箔的点蚀行为以及腐蚀箔性质的影响。使用二次离子质谱仪分析了轧制及退火铝箔中锰的元素分布。结果表明,锰在铝箔中的深度分布随着锰含量的增加而变化,但退火后铝箔中形成的立方织构的体积分数保持稳定。随锰含量增加,锰在退火铝箔表面的偏聚趋势增强。在相同的加电腐蚀条件下,腐蚀后锰含量高的铝箔表面具有更高密度的方形点蚀孔,并且并孔更少,点蚀孔分布更加均匀。在所研究的范围内(2.3~14.7μg/g),在520 V形成的腐蚀箔的比电容随锰含量的增加而提高。     

酸碱预处理对高压电子铝箔腐蚀扩面的影响

目的研究高压电子铝箔在Na OH和HCl溶液中的电化学行为,分析酸、碱预处理对铝箔电化学腐蚀扩面效果的影响。方法比较铝箔在不同浓度Na OH,HCl溶液中的预处理效果。采用极化曲线获得铝箔在各预处理溶液中的电化学参数,研究其腐蚀行为。利用扫描电子显微镜观察预处理后铝箔的表面形貌,分析预处理对铝箔表面形貌的影响。观察铝箔腐蚀扩面后的蚀孔形貌及蚀孔分布,分析预处理对蚀孔的影响。结果预处理减弱了铝箔制造过程中形成的表面不均匀,提高了表面活性,使得铝箔在电化学腐蚀处理中蚀孔密度增加,分布均匀。对未预处理铝箔及经HCl和Na OH预处理的铝箔进行电化学扩面处理,发现相对于未预处理的铝箔(比电容为0.56μF/cm2),经HCl溶液预处理的铝箔比电容提高了4%~8%,Na OH溶液预处理的铝箔比电容提高更为明显,约为13%~16%。铝箔在HCl溶液中的自腐蚀电位约为-820 m V,在Na OH溶液中的自腐蚀电位约为-1720 m V,并且经计算得知,铝箔在Na OH溶液中比在HCl溶液中自腐蚀速率快。结论铝箔在Na OH溶液中腐蚀均匀,用Na OH溶液对铝箔进行预处理,可以消除铝箔轧制缺陷,提高铝箔的比电容。     

碳钢在含热稳定性盐的N-甲基二乙醇胺介质中的腐蚀行为

利用阳极极化曲线法、Tafel曲线法和电化学阻抗谱法等技术,研究含有各种模拟热稳定性盐(HSS)的N-甲基二乙醇胺(MDEA)溶液在含氧与除氧条件下以及不同温度下对碳钢的腐蚀行为.结果表明,HSS的存在使碳钢的腐蚀速度加快.常温下HSS中的Cl-对碳钢的腐蚀性最强、可导致碳钢发生孔蚀;溶解氧的存在有利于降低既定HSS的腐蚀性.温度升高,碳钢的全面腐蚀速度增加,宏观孔蚀受到抑制;在含HSS的MDEA溶液中,碳钢腐蚀反应的阴极过程为电化学反应和扩散传质混合控制,阳极过程为电化学反应控制.     

Al-Zn-Sn-Ga合金点蚀行为及扩展机理

通过分析Al-7Zn-0.1Sn-0.015Ga(质量分数,％)合金在3.5％ NaCl溶液中的点蚀形貌及电化学阻抗谱(EIS)研究该合金的点蚀行为及扩展机理.结果表明:该合金析出相界面处由于Cl-吸附和微电池的共同作用优先溶解引发点蚀.蚀孔内金属离子浓度增加,Cl-向孔内迁移导致孔内Cl-浓度升高,同时孔内金属离子水解使孔内H+浓度升高,蚀孔迅速纵深发展.随着析出相溶解及孔深增加,腐蚀产物在蚀孔处堆积造成金属离子传质阻力增大,产生浓差极化导致蚀孔底部电位正移,纵向腐蚀速率减慢;回沉积在蚀孔处的Ga和Al形成Ga-Al汞齐,分离氧化膜使铝基体不断溶解,也使腐蚀产物不断脱落,使点蚀坑横向扩展.     

G105钢钻杆在不同浓度NaCl溶液中的高温高压腐蚀及常温电化学行为

目前,对G105钢钻杆在不同Cl-浓度下的腐蚀研究较少,通过高温高压釜模拟石油井动态高温高压环境,研究了G105钢钻杆在不同浓度NaCl溶液中的高温高压腐蚀行为,采用极化曲线研究了其常温电化学腐蚀行为。采用体式显微镜和扫描电镜(SEM)观察腐蚀产物膜形貌;采用X射线能谱分析仪(EDS)分析了腐蚀产物膜成分。结果表明:G105钢钻杆在含Cl-介质中发生孔蚀,严重时会出现明显的蚀坑;随着Cl-浓度的增加,钻杆的腐蚀速率和程度增加。     

2507双相不锈钢在不同Cl~-含量冷却水中的腐蚀行为

采用失重法、扫描电镜和能谱分析及电化学测试研究了2507双相不锈钢在4种Cl-含量冷却水模拟溶液中浸泡60d后的腐蚀行为。结果表明:2507双相不锈钢的腐蚀程度均属于轻度腐蚀,平均腐蚀速率随着Cl-浓度增加先升后降,Cl-的质量分数约在237mg/L时平均腐蚀速率达到最大。但随着Cl-浓度增加孕育点蚀的灰斑数量先升后降再升,Cl-的质量分数在237mg/L时灰斑数量最少。均未出现点蚀坑,点蚀电位高达约1.2V。     

小孔腐蚀在铝电解电容器用铝箔质量评价中的应用

阐述小孔腐蚀在铝电解电容器用铝箔质量评价中的应用机理。首先简要介绍电容器铝箔立方织构的形成过程和特征,及小孔腐蚀的一般电化学特点;然后模拟计算多晶体铝箔材料各晶面弹性模量、各晶面原子密度和各晶向原子密度;最后用HCl、HNO3、HF组成的特定侵蚀剂对电容器铝箔实施小孔腐蚀,用扫描电子显微镜(SEM)和光学显微镜(OM)对小孔腐蚀后的铝箔表面形貌与横截面形貌进行观察分析。电容器铝箔侵蚀后表面呈现大量正方形蚀孔,电容器铝箔发生小孔腐蚀具有方向性,蚀孔隧道总是沿着垂直或平行于铝箔表面的方向发展;100、110和111晶向的原子密度依次为2/a、2.12/a、1.15/a,a为晶胞参数,{100}、{110}和{111}晶面的原子密度依次为5/a2、4.24/a2、13.85/a2,{100}、{110}和{111}晶面的弹性模量依次为98.418、109.449、113.2678 GPa,蚀孔隧道活性尖端由{111}晶面构成以降低表面能,蚀孔隧道钝化壁由{100}晶面组成以保持钝化膜稳定。电容器铝箔正方形点蚀表面形貌与铝箔织构有特定的对应关系,织构{100}001含量可以通过计算铝箔表面正方形蚀坑面积的方法来估算。     

Effect of pretreatment on electrochemical etching behavior of Al foil in HCl–H2SO4

The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H₃PO₄ or 0.125 mol/L NaOH solution at 40 °C for different time and then DC electro-etched in 1 mol/L HCl+2.5 mol/L H₂SO₄ electrolyte at 80 °C. The pitting potential and self corrosion potential of Al foil were measured with polarization curves (PC). The potentiostatic current—time curve was recorded and the surface and cross section images of etched Al foil were observed with SEM. The electrochemical impedance spectroscopy (EIS) of etched Al foil and potential transient curves (PTC) during initial etching stage were measured. The results show the chemical pretreatments can activate Al foil surface, facilitate the absorption, diffusion and migration of Cl^? onto the Al foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched Al foil.     

Anodic Behavior of a Titanium–Aluminum Hybrid Electrode: Formation of Hydroxide-Oxide Compounds

The electrochemical behavior of a titanium–aluminum hybrid electrode in aqueous solutions of electrolytes containing halide ions (F^– and Cl^–) was studied. The effects of current density, solution composition, and ratio of the working surface area of titanium and aluminum on the anodic dissolution rate of a Ti?Al hybrid electrode and its electrochemical characteristics were revealed. The joint anodic dissolution of aluminum and titanium in the aqueous media under study made it possible to obtain precursors of the highly disperse oxide system Al₂O₃–TiO₂. Data of X-ray and electron-microscopic analysis confirmed the results obtained.     

Effect of pass deformation on microstructure, corrosion and electrochemical properties of aluminum alloy anodes for alkaline aluminum fuel cell applications

The effect of pass deformation in rolling processes on the microstructure, corrosion resistance and electrochemical activity of Al-Mg-Bi-Sn-Ga-In alloy anodes operated in an alkaline solution (85 °C, 5 mol·L^?1 NaOH with addition of NaSnO₃) with current density of 800 mA·cm^?2 was investigated. To analyze the microstructure of aluminum alloy anodes, we used scanning electron microscope, transmission electron microscope and electron backscatter diffraction techniques. We also used the hydrogen evolution method and electrochemical testing techniques to investigate the corrosion and electrochemical behavior of aluminum alloy anodes. The results showed that uniform microstructures with homogeneous distribution of fine active segregated phases as well as an excellent electrochemical performance of the aluminum alloy anodes were achieved by the dynamic recrystallization under pass deformation of 40%. We found that the aluminum alloy anodes (under pass deformation of 40%) had the lowest hydrogen evolution rate (0.092 mL·min^?1·cm^?2) and the most negative electrode potential (?1.585 V).     

纯铝1060在中国南沙群岛严酷海洋大气中的腐蚀以及点蚀行为

通过质量损失测量、扫描电子显微术、能谱分析、X射线光电子能谱和电化学阻抗谱等技术研究纯铝1060在南沙群岛海洋大气环境中暴露34个月后的腐蚀行为以及点蚀行为.结果表明,在纯铝表面发生严重的点蚀,并且暴露13个月后的平均腐蚀速率达到1.28 g/(m2·a).X射线光电子能谱的测试结果表明主要的腐蚀产物为Al2O3、Al...     

Erosion–corrosion behavior of aluminum in a 50°C ethylene glycol aqueous solution simulating cooling water in HVDC transmission

The erosion–corrosion of aluminum in a 50 °C ethylene glycol aqueous solution (EGAS) was studied. Compared with that in deionized water, the corrosion of aluminum in an EGAS was inhibited to a certain extent. The corrosion potential, corrosion current, and charge transfer impedance of aluminum changed from −1.5776 V, 380.4 nA cm⁻², and 1.924 × 10⁻⁴ Ω cm⁻² in deionized water to −1.3127 V, 285.5 nA cm⁻², and 4.041 × 10⁻⁴ Ω cm⁻² in a 45.3 vt% EGAS, respectively. Ethylene glycol did not ionize in deionized water and the ionic conductivity of the EGAS was low, effectively restraining the corrosion of aluminum. However, a test with aluminum in an EGAS after long-term storage (9 days) showed that ethylene glycol gradually oxidized to glycolic acid, oxalic acid, and other substances, which slowly corroded the aluminum surface. Analysis results showed that the corrosion products on the surface of aluminum were Al(OH)₃ and Al₂O₃. The pitting hole formation mechanism of aluminum occurs via an aluminum–alcohol phase formed on the aluminum surface, which can inhibit the dissolution of the oxide film. Therefore, a suitably concentrated EGAS with a high heat capacity and low ionic conductivity similar to that of deionized water can be used as a coolant in airtight valve cooling systems for high-voltage direct-current transmission.     

Effects of polymer corrosion inhibitor on widening etch tunnels of aluminum foil for capacitor

We investigated the effects of polymeric corrosion inhibitor polystyrene sulfonic acid (PSSA) additive to 3% HNO₃ solution on widening tunnels of pre-etched aluminum foil by electrochemical DC etching for aluminum electrolytic capacitors, using scanning electron microscopy and polarization curves. With trace PSSA, the dissolution of exterior surface of etch tunnels of Al foil is suppressed and the dissolution of interior surface of etch tunnels of Al foil is facilitated, respectively. The tunnels transform from circular cone to circular column in shape and pits-merging on the surface is weakened, leading to significant increase in the surface area and specific capacitance of the Al foil. The amounts of reduced thickness and weight of Al foil during the widening process of etch tunnels can be decreased if PSSA is employed.     

The flow corrosion mechanism of copper base alloys in sea water in the presence of sulphide contamination

A relationship between mass transfer conditions for condenser tubes in service and electrochemical rotating disc electrode experiments based on mass transfer coefficients analogies is proposed. A reaction order of one has been found for the reduction of oxygen on copper base alloys, and the elementary anodic dissolution processes under flow conditions has been studied. The pollution of the sea water by sulphide results in the formation of a contaminated surface film which has better electrocatalytic properties for O₂ reduction than the cuprous oxide films formed in clean aerated sea water. In most cases, the anodic process remains unaltered and the deleterious effect of sulphide is only related to the increase of the cathodic process rate. None of the materials studied showed any significant resistance towards this pollutant, in a procedure designed to test material behaviour under variable S^2? contamination.     

Characteristics of TiNi Shape Memory Foils Fabricated by Double Cathodes Electrochemical Polishing

Ti₅₀Ni₅₀ shape memory foil with 25 μm in thickness and having two smooth surfaces can be fabricated by an electrochemical polishing technique. This technique, using double cathode plates, may shorten the polishing time and alleviate the over-etched pitting effect. The grains on the surface of the hot-rolled sheet are elongated along the rolling direction, and those in the center of the electrochemically polished foil are equal-axial with an average grain size of approximately 8.5 μm. Both transformation temperature and enthalpy of the electrochemically polished foils decrease with the decreasing specimen’s thickness. The fabricated Ti₅₀Ni₅₀ foils possess the advantages of a more uniform chemical composition throughout the specimen, larger grain size, larger foil area, and greater thickness than those of sputtered TiNi thin films and melt-spun TiNi ribbons.     

Effect of aluminum on the corrosion resistance of low‐alloy steel in 10 wt% sulfuric acid solution

The aqueous corrosion behavior of low‐alloy steel with aluminum contents was examined in a 10 wt% H₂SO₄ (pH 0.13) solution using electrochemical techniques and surface analyses. The corrosion resistance of the new alloy steel was evaluated in terms of electrochemical parameters, such as passive current density, film, and charge transfer resistances. The results showed that a high Al content in the steel imparted better passivation behavior resulting in a lower corrosion rate. It related to the enrichment of iron carbonate and hydrocarbon by the dissolution of the carbide phase.