NaCl溶液中铜和A_3钢接触腐蚀的研究

研究了金属铜与A3钢在NaCl溶液中偶接时的接触腐蚀行为。考察了偶接时间、溶液中Cl-浓度、电偶对中阴阳极面积比、实验温度等因素对阳极腐蚀速度的影响。结果表明,腐蚀速度随温度升高、溶液中Cl-浓度的增大、阴阳极面积比的增大而增大;偶接时间为24 h时,腐蚀速度趋于稳定。     

NaCl溶液中铜和A3钢接触腐蚀的研究

研究r金属铜与A3钢在NaCl溶液中偶接时的接触腐蚀行为。考察了偶接时间、溶液中cl-浓度、电偶对中阴阳极面积比、实验温度等因素对阳极腐蚀速度的影响。结果表明,腐蚀速度随温度升高、溶液中Cl-浓度的增大、阴阳极面积比的增大而增大;偶接时间为24h时,腐蚀速度趋于稳定。     

碳钢在盐水中电偶腐蚀的影响及防护

１电偶腐蚀的影响因素（１）面积效应（阴极和阳极之间的面积比）是电偶腐蚀的一个重要因素，对腐蚀速度有着重大的影响，随着阴极对阳极面积比的增大，阳极金属的腐蚀增大。（２）氯化钠浓度低于１％时，腐蚀速度随其增高而增大；等于１％时，腐蚀速度达到最大值；高于１...     

09MnNiDR与不锈钢在3.5%的NaCl溶液中的电偶腐蚀行为研究

对比了电偶对材料的自腐蚀电位和各自的极化曲线,以及同一阴阳极面积比下,偶接后的混合电位和电流密度,研究了09MnNiDR和不锈钢(316L、304冷轧板、304热轧板、201)电偶对在3.5%的Na Cl溶液中的电偶腐蚀特性。结果表明,09MnNiDR处于活化状态,4种不锈钢则比较稳定;不锈钢的自腐蚀电位高于09MnNiDR,偶接后不锈钢作为阴极被保护,而09MnNiDR作为阳极腐蚀加剧。电偶腐蚀效应的大小为:09MnNiDR/316L09MnNiDR/20109MnNiDR/304热轧板09MnNiDR/304冷轧板。     

钛钢复合板在海水中电偶腐蚀研究

电偶腐蚀电位接近碳钢自腐蚀电位,不随面积比的增大而变化;电偶腐蚀电流密度和腐蚀深度,随阴阳面积比的增加成倍增大。钛钢复合板制设备一旦内层钛局部腐蚀穿孔,钛与碳钢形成大阴极小阳极的电偶对,很大的电偶腐蚀电流密度作用在碳钢上,使碳钢加速腐蚀,造成设备早期失效。     

碳钢/钛合金复合材料在3%NaCl溶液中的电偶腐蚀研究

采用失重方法和电化学方法,研究碳钢/钛合金复合材料在3%NaC l溶液中的电偶腐蚀行为。结果表明,在碳钢/钛合金电偶腐蚀过程中,碳钢为阳极,钛合金为阴极,随着阴/阳面积比的增大,电偶电流增大,碳钢腐蚀速率变大,而电偶电位基本不变。     

N80钢在几种压井液中的腐蚀规律的研究

利用静态失重法研究了溶液温度和溶液比重对N80钢在KCl、CaCl_2、NaNO_3溶液中腐蚀速度的影响,并通过添加缓蚀剂研究了缓蚀剂在三种压井液中的缓蚀作用。结果表明,随着温度的升高,N80腐蚀速度逐渐增大,随着溶液比重的增大,N80钢的腐蚀速度逐渐降低。三种压井液对N80钢的腐蚀性大小顺序为:KCl溶液CaCl_2溶液NaNO_3溶液。缓蚀剂的加入使得腐蚀速度大大降低。     

温度对碳纤维复合材料与金属间电偶腐蚀电流的影响

研究了温度对T700碳纤维复合材料(CFRP)与不锈钢和6061铝合金之间的电偶腐蚀的影响,以及电偶腐蚀电流及其腐蚀速率对材料表面形貌的影响。结果表明:CFRP与6061铝合金在氯化钠(NaCl)电解质溶液体系中会发生电偶腐蚀,而CFRP与不锈钢在NaCl电解质溶液体系中则会发生较小的电偶腐蚀;随着温度的增加,CFRP与6061铝合金发生的电偶腐蚀电流、平均电偶腐蚀速率相应增大,表面腐蚀现象更加严重;在NaCl电解质溶液体系中电偶腐蚀作用对CFRP影响不大,CFRP基本没有受到腐蚀。     

镀锌钢在模拟大气腐蚀环境的初期腐蚀行为研究

利用失重试验、极化和电化学阻抗技术研究了镀锌钢在不同温度和不同Cl~-含量的雨水中的初期电化学腐蚀行为。采用电镜扫描测试(SEM-EDS)技术分析腐蚀试样的形貌和成分。结果表明,温度和Cl~-浓度是影响镀锌钢在腐蚀溶液中腐蚀速率的主要因素,随着温度升高,镀锌钢在腐蚀溶液中腐蚀速率增大;随着Cl~-浓度增大,镀锌钢在腐蚀溶液中腐蚀速率呈现了先增后减的趋势,Cl~-含量7 g/L时,腐蚀速率最大。     

2Cr13不锈钢在含饱和CO_2盐溶液中的缝隙腐蚀行为研究

通过电化学动电位极化方法研究了2Cr13不锈钢在含饱和CO2盐溶液中的缝隙腐蚀行为。考察了温度、NaCl浓度以及HAc浓度对缝隙腐蚀的影响规律,结果表明:2Cr13钢缝隙腐蚀击破电位低于点蚀击破电位,同条件下更易引发缝隙腐蚀,且随温度、NaCl浓度、HAc浓度升高,缝隙腐蚀击破电位逐渐下降,缝隙腐蚀诱发阻力减小,缝隙腐蚀倾向增大,2Cr13钢耐缝隙腐蚀性能降低。在该介质中,腐蚀发生时,缝隙部位作为阳极加速腐蚀,缝隙外部作为阴极而得到保护。     

Galvanic studies related to the use in desalination plant of corrosion-resistant materials

Galvanic currents and potentials have been measured for bimetallic couples involving carbon steel, three grades of stainless steel, 90 Cu/10 Ni and titanium when exposed to seawater in the laboratory at temperatures of 18C and 60C and varying oxygen content. The galvanic currents flowing between couples consisting of two of the corrosion-resistant materials were very small. The galvanic corrosion rate of carbon steel, when connected to one of the other materials, was dependent upon the cathodic-polarisation characteristics of the noble-material surface with indications that, at a given area ratio, the galvanic corrosion of carbon steel was greater when coupled to the 90 Cu/10 Ni alloy than when connected to stainless steel or titanium. The usual effects of increasing the anode/cathode area ratio were observed and data were obtained to demonstrate quantitatively the significant beneficial effect of coating the cathode in a bimetallic couple. Intermediate air exposures were not found to promote any large, long-term, effects on galvanic corrosion. There was evidence that galvanic corrosion rates were very small when the dissolved oxygen content was controlled at low levels and some interesting aspects of galvanic corrosion at the higher temperature were noted.     

Localized corrosion of carbon steel in a CO2-saturated oilfield formation water

In this work, corrosion and localized corrosion behavior of X65 pipeline steel were studied in a simulated, CO₂-saturated oilfield formation water by various electrochemical measurement techniques, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves, galvanic current and localized EIS (LEIS). The morphology and composition of the formed corrosion scale were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. A conceptual model was developed to illustrate the occurrence of localized corrosion of the steel under scale. Both galvanic current and LEIS measurements showed that a galvanic effect existed between the bare steel and the scale-covered region. The scale-covered region served as cathode and the bare steel site as the anode. The big cathode vs. small anode geometry accelerated the local corrosion reaction. At an elevated temperature, a compact, crystalline scale was formed on the steel surface, enhancing the galvanic effect. Moreover, the stability of the scale was increased with time, and localized corrosion of the steel under scale experienced mechanistic changes with time.     

Electrochemical properties and corrosion protection of stainless steel for hot water tank

The state in which a stainless steel (STS) exhibits a very low corrosion rate is known as passivity, which is self-healing in a wide variety of environments. However, for those STS the corrosion includes pitting, crevice corrosion, galvanic corrosion, hydrogen embrittlement and stress corrosion cracking etc. And the corrosion resistance of STS is affected by area ratio, solution temperature and solution condition etc. Corrosion characteristics of STS 304, welding parts STS 316, STS 329 and STS 444 were investigated with parameters such as corrosion potential, galvanic current measurements, cathodic and anodic polarization behaviors as a function of area ratio and solution temperature in solution for hot water tank. It was found that galvanic current is affected by the area ratio, temperature and a kind of STS for hot water tank. Corrosion potential of welding part STS 316 was lower than that of STS 304, STS 329, STS 444 in solution for #1, #2 hot water tank. Therefore, it is suggested that the welding part STS 316 acts as anode for the other STSs. The amplitude of galvanic current between welding parts STS 316 and STS 304, STS 329, STS 444 in #1 solution is smaller than that in #2 solution. This is the reason that chloride ion quantity in #2 solution is more than that for #1 solution. And then welding part STS 316 corrodes easily by acting as anode compared to the other STS.     

A study of the mechanisms of corrosion inhibition of AA2024-T3 by vanadates using the split cell technique

The mechanisms of corrosion inhibition of AA2024-T3 by vanadates were studied in this work using the split cell technique and polarization curves. The electrochemical behavior of clear solutions containing metavanadates and orange solutions containing decavanadates was clearly distinctive. Injection of metavanadates to the cathode side of the different split cell setups greatly reduced the galvanic current, indicating a potent inhibition of the oxygen reduction kinetics. The galvanic current never exhibited a transient current peak, suggesting that metavanadates inhibit AA2024-T3 corrosion by a mechanism that does not involve electrochemical reduction. Injection of metavanadate to the anode side of the different split cells had no effect on the galvanic current. Injection of orange decavanadate to the cathode side of the AA2024-T3 split cell resulted in a large current peak, associated with the electrochemical reduction of decavanadate. However, decavanadates did not impart significant corrosion protection.     

印刷电路板Cu-焊锡界面局部腐蚀行为特性研究

原位测定金属/溶液界面微区物化参数分布对研究金属局部腐蚀的发生、发展机理有重要意义。本研究应用扫描微参比电极（SMRE）技术对NaC l溶液中印刷电路板Cu-焊锡界面局部腐蚀早期表面微区电位分布进行测量。结果表明：在0.5mol/LNaC l溶液中焊锡电极电位基本稳定在-0.47V附近,纯铜电极的电位基本稳定在-0.19V附近,两者差别较大;Cu/焊锡浸入0.5mol/L NaC l溶液中前期局部腐蚀发生在Cu与焊锡相接触的界面上且腐蚀程度随时间逐渐达到最大。后期焊锡作为阳极腐蚀逐渐加剧而铜作为阴极受到保护,腐蚀程度逐渐减弱,直至焊锡最终全面腐蚀。     

Effect of external wall defect growth on internal wall corrosion of oil pipelines under mechano-electrochemical interaction

The corrosion mechanism of X80 steel in simulated solutions of acid red soil and product oil sediment under mechano-electrochemical interaction (MEI) was researched to build a new finite element model through multi-physical field coupling simulation technology. Based on the new model, the effect of external wall defect growth on the internal wall corrosion of oil pipelines was analyzed in detail. The results showed that the distributions of stress and corrosion of the internal wall were extremely affected by the external wall defect depth, and the corrosion rate of the internal wall was enlarged remarkably by the external wall defect growth. Moreover, attributing to the local galvanic cell effect under MEI, the growth rates of corrosion defects in the depth and length directions of the external defect were accelerated because these directions were associated with larger stress and equivalent to the anode, but the corrosion rate in the width direction of the external defect was inhibited because this direction was associated with smaller stress and equivalent to the cathode.     

Underscale corrosion behavior of carbon steel in a NaCl solution using a new occluded cavity cell for simulation

A new occluded corrosion cavity (OCC) simulation cell was designed to study the underscale corrosion behavior of carbon steel (N80) in 0.2 mol L⁻¹ NaCl solution. The chemical components of the solution in the OCC were measured and the electrochemical behavior of the occluded anode and the bulk cathode were studied by electrochemical impedance spectroscopy (EIS). The newly designed OCC cell can easily simulate the auto-catalyzing acidification process and may be used to study the mechanism of underscale corrosion. The corrosion scale exacerbates the underscale corrosion and the area ratio of the bulk cathode to the occluded anode (R = S_c/S_a) determines the development of simulated localized corrosion in the OCC cell. When R was within a certain range, the corrosion rate in the OCC could be kept at a persistently high level. The pH of the solution in the OCC decreased and the chloride ions (Cl⁻) concentrated as the local corrosion developed. The anodic process on the occluded anode was controlled by irreversible charge transfer and the cathodic process on the bulk cathode was controlled mainly by oxygen diffusion.