外加电流阴极保护用辅助阳极的研究现状及发展趋势

辅助阳极是外加电流阴极保护系统的重要组成部分。本文就辅助阳极的形状及尺寸、辅助阳极材料的耐蚀性能及加工性能、辅助阳极的布置及电场的分布、辅助阳极设计的数据库研究等四个方面对外加电流阴极保护用辅助阳极的研究现状及发展趋势进行了综述。     

高电位镁牺牲阳极研究进展

概述高电位Mg-Mn牺牲阳极组织、电化学性能特点以及应用,分析杂质元素Ca、Sr、Mn元素和熔铸新工艺对高电位镁阳极组织和电化学性能的影响、Zn含量对Mg-zn超高电位镁阳极电化学性能的影响,挤压高电位镁阳极的生产工艺及应用,指出高电位镁阳极存在的问题并对其发展趋势进行展望。     

稀土元素和固溶处理对Al阳极电化学性能的影响

对Al-Zn-In-Sn-Mg和Al-Zn-In-Sn-Mg-RE 2种Al合金 阳极进行固溶处理，测定了经固溶处理和未经固溶处理的阳极在20℃和65℃的3%NaCl溶液中 的电化学性能 .结果表明,高温下Al阳极电流效率普遍下降，腐蚀变得不均匀;添加RE的固 溶处理阳极在65℃时性能优良；固溶处理可改善Al阳极在高温介质中的性能.讨论了RE及固 溶处理对高温介质中Al阳极性能的影响.     

镁基牺牲阳极研究进展

综述国内外镁基牺牲阳极的最新研究进展及应用,重点介绍了纯镁高电位镁阳极、Mg-Mn高电位镁阳极、分别添加Ca、Sr、Zn元素新型高电位镁阳极、低电位钱牺牲阳极电化学性能和组织特点,分析了合金元素、杂质元素、熔铸工艺对镁基牺牲阳极电化学性能和组织的影响,指出镁阳极存在的问题和发展方向.     

合金元素对铝基牺牲阳极性能的影响

通过合金化方法,在Al-Zn-In三元牺牲阳极中依次添加Mg、Ti、Ga、Mn、Sn等元素,炼制不同成分的铝合金牺牲阳极。采用电化学性能测试、极化曲线测量及扫描电子显微镜分析等手段分析了合金元素对铝合金牺牲阳极性能的影响。结果表明,随着添加元素种类的增加,牺牲阳极电化学性能提高。在Al-Zn-In三元阳极中加入Mg和Ti,阳极溶解形貌更加均匀;加入Ga与Sn后,阳极的开路电位与工作电位负移;加入Mn后阳极的电流效率提高。     

阳极氧化工艺对6061铝合金草酸氧化膜耐磨耐蚀性的影响

为改善6061铝合金的表面耐磨性能和耐蚀性能,利用阳极氧化技术在草酸电解液中制备了阳极氧化膜。采用显微硬度仪测试了膜层的显微硬度,利用摩擦磨损试验机(CSEM)研究阳极氧化膜的摩擦性能,利用电化学阻抗谱(EIS)分析氧化膜的抗腐蚀性能。研究了阳极氧化电流密度、电解液温度以及阳极氧化时间对氧化膜的硬度、耐磨性及耐蚀性的影响规律,给出综合性能较好的阳极氧化工艺参数:电解液为40 g·L-1的草酸,阳极氧化温度为10℃,阳极氧化电流密度为1.0 A·dm-2,阳极氧化时间为120 min。     

我国钛阳极开发应用现状及水平

我国有金属阳极电槽１２多万台,大约有３７万支隔膜阳极,离子膜阳极有１７０００ｍ＾２,６４００台单元槽,阳极用钛约４０００ｔ,国内氯碱阳极与国外同类阳极性能仍有差距,主要表现在寿命短,单耗高,运行电流密度及电流效率都低等。国内还开展了特种阳极研究,并在次氯酸钠发生器,外加电流阴极保护,海水电解防污,ＰＳ版生产中得到应用,此类阳极性能水平与国外差距不大,但铜箔生产用阳极的性能远不如国外的。     

氨基酸类有机添加剂对镁合金阳极氧化的影响及其作用机制研究

为了进一步改善镁合金表面阳极氧化膜的质量和性能,在Na OH+Na_2SiO_3基础电解液中添加氨基酸类有机添加剂对AZ31镁合金进行阳极氧化,研究了氨基酸类有机添加剂对镁合金阳极氧化过程及氧化膜厚度、表面形貌、结构及耐蚀性的影响。探讨了有机添加剂在镁合金阳极氧化中的作用机制。结果表明:不同的氨基酸对镁合金阳极氧化过程及氧化膜性能影响不尽相同,其中乙二胺四乙酸和L-鸟氨酸醋酸盐可显著提高阳极氧化的击穿电压,起到明显的抑弧作用,大幅度提高了氧化膜的厚度、致密性和耐蚀性能。有机添加剂主要通过缓蚀、抑弧和表面活性剂3方面的综合作用来影响镁合金阳极氧化的过程及氧化膜的性能。     

葡萄糖对铝合金电极电化学活性及自腐蚀的影响

针对铝-空气电池放电时铝合金阳极自腐蚀严重的问题,利用失重法、线性扫描伏安法等电化学方法研究了葡萄糖作为铝合金阳极缓蚀剂的缓蚀效果,以及葡萄糖对铝合金阳极电化学性能、空气电极电化学性能的影响,并利用XRD及金相组织形貌对放电后的铝合金阳极表面进行葡萄糖的缓蚀机理分析。结果表明,添加葡萄糖能够使铝合金阳极利用率由45%提高至90%,能适当提高铝合金阳极的电流密度约12 mA/cm2,且几乎不影响空气阴极的电化学性能。XRD及金相组织表明,添加葡萄糖能够促使铝合金阳极表面放电过程中产生的氢氧化铝脱落而使铝合金表面光滑平整。     

铝合金阳极氧化的研究进展

对铝合金的阳极氧化工艺技术进行了阐述,深入分析了阳极氧化膜层的成膜机理,并对铝阳极氧化膜层的微观结构及性能进行了总结,讨论了铝阳极氧化技术近来的发展及未来的应用。     

Mechanism of intergranular attack in Zn–Al–Cd sacrificial anodes at elevated temperatures

Abstract

The premature failure of a Zn–0·3 Al–0·03Cd anode at 70°C in sea bed mud has been simulated in laboratory sea water using galvanostatic polarisation. The exposed surface of the anode suffered intense intergranular attack and some dissolution. Within the bulk of the material intergranular attack was observed, but no dissolution. Unpolarised alloys in a variety of environments exhibited the same type of attack; however, it could not be produced on pure zinc. No evidence could be found of segregation or precipitation of aluminium at grain boundaries. Moreover, specimens that had been solution treated to ensure a single phase microstructure suffered from intergranular attack in short term simulation tests. It is concluded that a previously proposed mechanism consisting of grain boundary precipitation of aluminium followed by its preferential dissolution is incorrect. It is proposed from analysis of the fracture morphology and the effect of test conditions that the failure is caused by hydrogen penetration.     

牺牲阳极在海泥中电化学性能的影响因素

介绍了三种铝合金牺牲阳性在不同海域、不同温度的海泥中以及不同试验时间所得到的恒电流电化学性能测试的结果,并对试验结果进行分析讨论。     

Al-Zn-In-Si牺牲阳极在模拟海水及海泥环境中的电化学性能

目的 分析A13型Al-Zn-In-Si牺牲阳极在海水、海泥中的电化学性能.方法 采用恒电流极化进行4 d的加速实验,使用电化学阻抗谱(EIS)分析电化学腐蚀过程,通过扫描电子显微镜(SEM)、能谱分析(EDS)及三维超景深显微镜观察分析腐蚀形貌及表面化学成分,对比研究了Al-Zn-In-Si牺牲阳极在模拟海水和海泥环境下的腐蚀形貌、电化学性能.结果 在模拟海水和海泥环境中,尽管Al-Zn-In-Si牺牲阳极都满足DNVGL-RP-B401的要求,但在海泥环境中,其电化学效率仅为65.97％,远低于海水环境中的89.43％.牺牲阳极在海水环境中发生均匀腐蚀,而在海泥环境中却呈现严重的不均匀腐蚀现象,表面腐蚀坑为疏松多孔蜂窝状.结论 在海泥环境下,Al-Zn-In-Si牺牲阳极的腐蚀产物扩散困难,局部呈现腐蚀坑,自腐蚀速率高,导致电化学效率降低.溶解过程中,由于组织脱落,自身消耗增加,电化学容量降低,从而导致阳极在模拟海泥环境中的电化学性能低于海水环境,并揭示了阳极在模拟海水、海泥环境中的腐蚀机理.     

In situ study of the deep sea electrochemical performance of aluminum-based galvanic anodes

The galvanic performance of Al–Zn–In–Mg–Ti–Ga–Mn and Al–Zn–In–Si anodes was studied in situ in the South China Sea at a depth of 1,420 m when coupled to E355DD structural carbon steel. Deep-sea field tests showed that Al–Zn–In–Mg–Ti–Ga–Mn anode surface degradation mainly occurred via uniform corrosion accompanied by some minor evidence of pitting and intergranular corrosion, whereas the Al–Zn–In–Si anode was subject to extensive intergranular corrosion. Pitting and intergranular corrosion were primary reasons for degrading the galvanic anode performance, and overall the Al–Zn–In–Mg–Ti–Ga–Mn performed better than the Al–Zn–In–Si in the deep-sea environment. There was no evidence that calcareous sediments were deposited on the protected steel surface and the protection current density in the deep sea was 72% higher than that required at the ocean surface.     

Al-Bi-Pb-In-Ga合金牺牲阳极的组织与电化学性能研究

研制了一种Nl-Bi-Pb-In-Ga合金牺牲阳极；用恒电流法研究了合金在自来水、淡海水、人造海水介质中的电化学性能；用金相显微技术和扫描电子显微技术观察牺牲阳极的微观组织和腐蚀后的表面形貌；结果表明，合金化元素均匀弥散分布的Nl-Bi-Pb-In-Ga合金牺牲阳极在自来水、淡海水、人造海水介质中腐蚀溶解均匀，阳极极化弱，电极电位负，阳极利用率高。     

Corrosion failure of marine steel in sea‐mud containing sulfate reducing bacteria

The corrosion failure behavior of marine steel is affected by stress, which exists in offshore structures at sea‐mud region. The sulfate reducing bacteria (SRB) in the sea‐mud made the steel more sensitive to stress corrosion cracking (SCC) and weaken the corrosion fatigue endurance. In this paper, a kind of natural sea‐mud containing SRB was collected. Both SCC tests by slow strain rate technique and corrosion fatigue tests were performed on a kind of selected steel in sea‐mud with and without SRB at corrosion and cathodic potentials. After this, the electrochemical response of static and cyclic stress of the specimen with and without cracks in sea‐mud was analyzed in order to explain the failure mechanism. Hydrogen permeation tests were also performed in the sea‐mud at corrosion and cathodic potentials. It is concluded that the effect of SRB on environment sensitive fracture maybe explained as the consequences of the acceleration of SRB on corrosion rate and hydrogen entry into the metal.     

在役海底管线牺牲阳极失效分析

用恒电流试验、表面溶解形态、腐蚀产物X-ray衍射分析、 扫描电镜和能谱分析,对南海油田某海底输油管道的在役铝合金牺牲阳极的使用状况进行 了分析测试.结果证实,该阳极提前失效的原因是由于其组织结构存在缺陷,晶间偏析严重 导致晶间腐蚀所致.     

Revealing the effect of aluminum content on the electrochemical performance of magnesium anodes for aqueous batteries

Al is one of the principal alloying elements for Mg anodes. In this study, a series of Mg–Al alloys has been evaluated as anode materials for optimizing the Al addition amount in Mg anodes with the intention of improving the discharge performance in aqueous batteries. The effect of Al content on the discharge potential and corrosion resistance of the Mg anode has been investigated through microstructure characterization, electrochemical measurements in a half-cell, discharge morphology analysis, and Mg–water battery tests. The results show that the Mg–1Al alloy possesses a larger corrosion resistance during discharge, with significant increase of the anode utilization efficiency at 1 and 5 mA/cm² compared with pure Mg. However, a further increase of Al content does not continuously improve the discharge performance of the Mg anode with the decline of utilization efficiency due to the influence of the precipitated phase. This study contributes to a better understanding about the effect of Al on anodic dissolution and corrosion kinetics of the Mg anode.     

线性阳极在阳曲压气站区域性阴极保护中的应用

陕京三线阳曲压气站新建装置区的区域性阴极保护设计采用了线性阳极地床方式。针对线性阳极电流及电位分布特征,采用闭合回路安装,并设置阳极接线箱。现场测试表明,使用线性阳极克服了站内区域性阴极保护的干扰与屏蔽。     

Effect of rolling processing on microstructure and electrochemical properties of high active aluminum alloy anode

The effect of rolling processing on the microstructure,electrochemical property and anti-corrosion property of Al-Mg-Sn-Bi-Ga-In alloy anode in alkaline solution(80℃,Na2SnO3+5 mol/L NaOH)was analyzed by the chronopotentiometry (E-T curves),hydrogen collection tests and modern microstructure analysis.The results show that when the rolling temperature is 370℃,the electrochemical activity of Al anode decreases gradually with the increase of pass deformation in rolling,while the anti-corrosion property is improved in the beginning and then declined rapidly.When the pass deformation of rolling is 40%,the Al anode has good electrochemical activity as good as the anti-corrosion property and with the increase of rolling temperature,both electrochemical activity and anti-corrosion property of Al anode increase first and then decrease.When the rolling temperature is 420 ℃,the aluminum alloy anode has the most negative electrode potential of about-1.521 V(vs Hg/HgO)and the lowest hydrogen evolution rate of 0.171 6 mL/(min·cm2).The optimum comprehensive performance of Al alloy anode is obtained.