Simultaneous Investigation of Marine Factors Effect on Corrosion Rate of SS 304 in Turbulent Condition

Seawater is generally considered to be the most corrosive of the natural environments which threatens all the steel structures in their life time. The effect of environmental marine factors is extremely important in its corrosive behaviour. In this article, the influence of different marine parameters including pH, temperature, salinity and velocity is evaluated on the corrosion rate of SS 304 samples under turbulent condition. Since in actual marine environment, the entire parameters act simultaneously and as there is the possibility of differences between individual and synergistic influences of effecting factors, the influence of each considered parameter on the rate of corrosion has been studied under the combined effect of other factors. Finally, the results are presented via the graphs of dual factor effects which illustrate two-by-two influences of environmental parameters on corrosion rate variation. This research presents the difference between the qualitative and quantitative effects of a parameter under different ranges of considered parameter and also under the simultaneous effect of other combined acting factors, which emphasizes the importance of synergistic effects. In each case, the results obtained in turbulent condition are compared with previous study which had investigated the effect of marine parameters in laminar medium.     

Corrosion rate variation of SS 316 under simultaneous factors considering turbulence effect

Abstract

Investigation of corrosion rate under the simultaneous effect of parameters is a new and important approach that makes our experimental media closer to real condition and offers more realistic results. In this study, the effect of some important marine factors including temperature, pH, velocity and salinity on the corrosion rate of SS 316 is considered synergistically using two by two graphical curves. Experiments are performed in turbulence condition, and each parameter is applied at three levels. The results of this research are compared with the achievements of a former synergistic study of parameters, which had calculated the contribution percentage and qualitative influence of marine factors in laminar condition. This research presents the critical points in the change of corrosion rate under the synergistic effect of parameters and compares the capability of factors in changing the rate of corrosion and studies their qualitative effect.     

316L不锈钢微动磨蚀过程力学化学交互作用的迁移行为

用球-平面接触微动设备研究了316L不锈钢微动损伤速率随微动时间的变化,解析了316L不锈钢不同微动阶段的损伤机制.316L不锈钢微动分三个阶段第一阶段为微突体接触机制,犁沟损伤严重;第二阶段缝隙腐蚀的发生发展成为影响微动的主导因素;第三阶段是腐蚀疲劳微断裂所致剥层机制为主的损伤过程.力学化学交互作用分量在稳定阶段占损伤的60％以上,对316L不锈钢微动损伤影响显著;力学分量随微动过程的进行线性下降,腐蚀分量线性增长,但力学因素是材料微动损伤的主要因素.     

A study of abrasion–corrosion of AISI 304L austenitic stainless steel in saline solution using acoustic emission technique

In industrial environment, many materials are subjected to the abrasion–corrosion phenomenon. In such cases, stainless steels are often used for their good corrosion resistance. However, the synergistic effect between abrasion and corrosion may be a serious contributor to the total wear even when pure corrosion rates do not appear to be significant. In order to select the more resistant alloy for each particular application, it is important to understand this phenomenon. This paper presents a study on the characterization by acoustic emission and electrochemical techniques of AISI 304L stainless steel abrasion–corrosion, in saline environment. The abrasion mechanism is first examined for three angles of impingement in non-corrosive conditions. Then, the synergistic effect between mechanical damage and corrosion is investigated. The results indicate that the lower the impingement angle, the lower is the mechanical contribution. In corrosive conditions, it is shown that, at low abrasion rate, the synergistic effect depends on the impingement angle. Some hypothesis are proposed in order to separate, in the overall synergistic damage, the effect of abrasion on corrosion and the effect of corrosion on abrasion.     

螺旋流和缓蚀剂协同作用抑制管道冲刷腐蚀

目的 探讨螺旋流和缓蚀剂协同作用下的减蚀机理,为开发基于螺旋流的新型冲刷腐蚀控制方法提供理论支撑。方法 利用循环式管流冲刷腐蚀试验装置,结合失重测试法、电化学测试法、形貌分析、高速摄像和XPS腐蚀产物分析开展非螺旋流和螺旋流条件下加入水溶性咪唑啉缓蚀剂的管道冲刷腐蚀对比试验研究。结果 失重法和电化学测量结果一致表明:在非螺旋流和螺旋流条件下缓蚀剂对20号钢冲刷腐蚀的纯冲刷速率、纯腐蚀速率、腐蚀促进冲刷速率和冲刷促进腐蚀速率均具有有效的抑制作用,但对纯冲刷的缓蚀率均小于对其他三者的缓蚀率。螺旋流和缓蚀剂协同作用对纯冲刷速率、纯腐蚀速率、腐蚀促进冲刷速率和冲刷促进腐蚀速率4个分量的协同缓蚀率均高于缓蚀剂单独作用对4个分量的缓蚀率。其中对冲刷促进腐蚀分量的缓蚀率最高,达到93.75%。高速摄像结果表明扭带产生的螺旋流使砂粒切向速度增大,产生砂粒悬浮效应,改善了砂粒的分布状态。从形貌观察来看,螺旋流和缓蚀剂协同作用下工作电极表面腐蚀产物层最为完整致密且蚀坑数量最少。XPS分析证明了螺旋流和非螺旋流条件下缓蚀剂在电极表面的吸附且螺旋流促进了氧气和缓蚀剂的传质。结论 螺旋流产生的砂粒悬浮效应和传质增强效应进一步促进缓蚀剂对纯冲刷速率、纯腐蚀速率、腐蚀促进冲刷速率和冲刷促进腐蚀速率4个分量的抑制,更充分地发挥了缓蚀剂的缓蚀效果。螺旋流与缓蚀剂的协同作用在降低管道冲刷腐蚀方面具有潜在的优势。     

紧固件用GH4080A合金的应力腐蚀机制

采用慢应变速率拉伸实验研究了pH值、SO4^2-、Cl^-对GH4080A合金应力腐蚀行为的影响。结果表明:pH值越低,GH4080A合金的抗应力腐蚀性能越差;合金对中性条件下的Cl^-应力腐蚀敏感性不明显,但pH<7时,合金对Cl^-存在应力腐蚀敏感性,而且对HCl具有明显的应力腐蚀敏感性,主要源于H^+和Cl^-对应力腐蚀的协同作用;常温下GH4080A对含SO4^2-离子的介质不敏感。进一步的外加电位应力腐蚀实验表明,GH4080A合金应力腐蚀断裂机理为氢致开裂型,断口特征表现为沿晶脆性断裂。     

Synergistic influence of iodide ions on the inhibition of corrosion of C-steel in sulphuric acid by some aliphatic amines

The synergistic influence caused by iodide ions on the inhibition of corrosion of C-steel in 1 M H₂SO₄ in the presence of some aliphatic amines has been studied using weight loss, potentiodynamic polarization, linear polarization and a.c. impedance techniques. Aliphatic amines used inhibit the corrosion of C-steel and the inhibition efficiency increases by increasing the concentration of the additives and also by addition of iodide ions. The adsorption of these compounds is found to obey Frumkin’s adsorption isotherm. The increase in surface coverage in the presence of iodide ions indicates that iodide ions enhance the adsorption of these aliphatic amines on the metal surface. Defines and evaluates synergism parameter (S_θ). Values of the parameter which are more than unity indicate the fact that the enhanced inhibition efficiency in the presence of iodide ions is only due to synergism and there is a definite contribution from the inhibitors molecules, which are adsorbed by coulombic interaction on the metal surface, where iodide ions are already adsorbed and thus reduces the corrosion rate.     

Couple effect of hydrostatic pressure and dissolved oxygen on corrosion behaviour of low-alloy high strength steel in 3.5 wt-% NaCl solution

ABSTRACT

Hydrostatic pressure (HP) and dissolved oxygen (DO) both change with the increase of ocean depth. In order to unmask the corrosion phenomena of metals in deep sea environment, studying their combined effect on corrosion is necessary. In this report, couple effect of HP and DO (HP?+?DO) on corrosion behaviour of low-alloy high strength steel in 3.5 wt-% NaCl solution was investigated by Electrochemical measurements, SEM observations, XPS characterisations and 3-D size measurements. The results show that the corrosion rate of low-alloy high strength steel increases with increasing HP?+?DO under each immersion period, appearing an exponential decay growth. As HP?+?DO increases to a critical value, 30 ATO, its acceleration to corrosion process becomes limited. Moreover, HP?+?DO remarkably increases the growth of corrosion film on steel surface and leads to more loose structure in corrosion film. Finally, HP?+?DO stimulates the propagation of corrosion pits in 3D direction.     

AISI 316不锈钢和Ti6Al4V合金在海水环境中的腐蚀与腐蚀磨损行为(英文)

采用立式万能销盘腐蚀磨损试验机研究AISI 316不锈钢和Ti6Al4V合金在海水中与Al2O3陶瓷对磨时的腐蚀与腐蚀磨损行为,重点讨论腐蚀磨损之间的交互作用。结果表明,摩擦作用使得Ti6Al4V合金和316不锈钢的开路电位大幅下降,腐蚀磨损过程中的电流密度远高于静态腐蚀时的电流密度,摩擦明显促进了合金的腐蚀。两种合金在海水中的磨损量远大于在纯水中的磨损量,腐蚀促进了磨损,并且Ti6Al4V合金的耐磨性优于316不锈钢的耐磨性,腐蚀磨损之间的交互作用是材料损失的一个重要因素。本实验所用的摩擦装置为单向滑动的面面接触方式,这使得摩擦对腐蚀的促进作用在总磨损量中所占的比例很小。     

Synergistic inhibition effect of N-(furan-2-ylmethyl)-7H-purin-6-amine and iodide ion for mild steel corrosion in 1 mol/L HCl

The synergistic inhibition effect of N-(furan-2-ylmethyl)-7H-purin-6-amine (FYPA) and iodide ion on mild steel corrosion in 1 mol/L HCl was investigated using weight-loss tests, electrochemical techniques, and surface analysis. The experiments revealed that the FYPA + KI mixture was a temperature-dependent inhibitor, which strongly inhibited the corrosion of mild steel compared with FYPA. Based on electrochemical results, FYPA and FYPA + KI behaved as mixed-type inhibitors, and their inhibition efficiencies were 73.66% and 96.01%, respectively. The calculated synergistic parameter value was larger than unity, illustrating that enhancement of inhibition in the presence of KI could be a result of synergistic action. Surface analysis techniques (scanning electron microscope/scanning electrochemical microscope) confirmed the presence of additives on the studied mild steel surface. A plausible mechanism of corrosion inhibition was proposed.     

316L不锈钢微动磨蚀过程力学化学交互作用研究

采用球－平面接触微动设备,对３１６Ｌ不锈钢在不同ＮａＣｌ溶液中微动过程力学化学交互作用进行了研究,并解析了材料微动损伤速率与溶液腐蚀特性之间的关系。结果表明,材料微动过程力学化学作用相互促进,力学损伤在微动损伤过程中占居主导作用。强碱性、强酸性及溶液富含Ｃｌ＾－的情况下,都可导致材料严重微动损伤,而在中性条件下,力学因素对化学损伤促进作用最为明显。     

Zn(NO3 ) 2 ·6H2O,Na2MoO4 ·2H2O 与 Na5P3O10对 1Cr18Ni9Ti 的协同缓蚀作用

目的研究硝酸锌、钼酸钠及三聚磷酸钠之间的协同缓蚀作用机理,使其在性能上实现互补。方法以酸性高锰酸钾溶液为基础,通过极化曲线和失重法实验,研究3种缓蚀剂对1Cr18Ni9Ti奥氏体不锈钢的协同缓蚀作用。结果硝酸锌和三聚磷酸钠以抑制不锈钢的阴极反应为主,钼酸钠则主要抑制不锈钢的阳极反应。硝酸锌与钼酸钠表现出明显的拮抗作用,导致缓蚀效果变差。只有当三聚磷酸钠加入后,三者之间才表现出了良好的协同作用,使总的缓蚀性能达到最优,复配后的缓蚀效率可以达到90%以上。结论硝酸锌、钼酸钠及三聚磷酸钠之间存在良好的协同缓蚀作用,可以明显降低1Cr18Ni9Ti不锈钢在酸性高锰酸钾溶液中腐蚀速率,从而延长设备的使用寿命。     

挤压镁合金腐蚀与防护研究进展

随着挤压镁合金的广泛应用,如何改善其较差的耐蚀性自然成为无可回避的重要研究课题。通过综合分析国内外挤压镁合金腐蚀研究领域的相关研究成果,从腐蚀行为与防护技术两个方面进行了讨论。挤压镁合金易于受到多种腐蚀形式的破坏,其腐蚀行为、性能和机理受到材料特性和腐蚀环境等多种因素的影响,表现出多样性和复杂性,特别是应力和腐蚀协同所用下的挤压镁合金失效行为,尚需开展深入研究。通过优化制备工艺参数、合金化和热处理等技术进行组织和成分优化,基于应力条件、不同的腐蚀环境,开发新型耐腐蚀挤压镁合金,对于提高挤压镁合金抗腐蚀性能,扩大其应用领域具有实用价值。电化学镀、化学转化膜、自修复涂层等涂层技术在合金表面形成钝化膜、陶瓷膜以及释放缓蚀剂,对挤压镁合金提供了有效防护。其中,自修复涂层能够有效解决涂层破损产生的局部腐蚀问题,极大地改善了膜层的防护性能,拥有良好的应用前景,是涂层研发的新方向。     

碳钢CO2腐蚀的缓蚀剂策略及缓蚀行为研究进展

从新型CO₂缓蚀剂合成制备、绿色动植物成分作为CO₂缓蚀剂开发、CO₂缓蚀剂协同效应研究、苛刻环境下的缓蚀剂性能探究、缓蚀剂构效分析及影响因素评价等5个部分对CO₂缓蚀剂的最新研究进展进行综述分析。针对现有部分缓蚀剂存在性能不足、污染大等问题，CO₂缓蚀剂的增效思路主要包括新型缓蚀剂分子合成、绿色缓蚀剂提取和缓蚀剂复配研究。新型缓蚀剂合成是通过有机化学反应，以杂环分子为原料进行结构设计、官能团接枝或修饰得到新型缓蚀剂分子。该部分同时介绍了纳米缓蚀剂的前沿发展及面临的瓶颈问题。绿色缓蚀剂提取是以天然动植物为原料，改善缓蚀剂的生态安全性，针对绿色缓蚀剂的快速发展提出“全流程”绿色控制理念，建议确立绿色定义标准。缓蚀剂协同效应研究旨在阐明不同缓蚀剂间复配增效的本质机理，当前需要建立快速评价体系，健全探寻最佳复配比的指导理论。另外，缓蚀剂在复杂或极端工况下的结构稳定性、缓蚀性能持久性和缓蚀机理变化对其实际应用至关重要，油气田开发苛刻环境下“防腐+”一体化试剂的需求增大。除上述制备与应用...     

慢应变速率下铝合金的腐蚀行为

根据铝合金腐蚀的基本特征，建立了新鲜铝合金瞬时腐蚀速率的计算方法。通过改变试样的应变速率，研究了力学效应对LC4CS铝合金腐蚀电化学行为的影响。结果表明：在恒应变速率作用下，铝合金自腐蚀电位有明显的负移趋势，且应变速率愈大，负移速率愈快。与阳极氧化后的铝合金短路耦合，在应变量大于0.04后，LC4CS铝合金的自溶解电流显示急剧增大的趋势。对同一应变速率而言，随着应变量的增加，新鲜铝合金的瞬时腐蚀速率也随之增大。     

Inhibition of the acid corrosion of iron with triphenyl tetrazolium chloride

The efficiency of 2, 3, 5-triphenyl tetrazolium chloride (TTC) as an inhibitor for acid corrosion of hot-rolled low carbon steel was studied. The effect of TTC on the corrosion rate was measured in 5 N H₂SO₄ at various temperatures and concentrations. It was found that TTC has a significant inhibiting effect on the corrosion of the metal; protection efficiencies approaching 97% were measured. The inhibitor shifts the free corrosion potential in the anodic direction and polarizes both the cathodic and the anodic half-reactions. The effect is more pronounced for the anodic half-reaction near the corrosion potential. It changes the apparent activation energy of corrosion to a value characteristic of diffusion processes.     

盐酸介质中苯扎溴铵在铁表面的吸附行为及其与肉桂醛的协同缓蚀作用

采用失重法和极化曲线法研究了Fe在苯扎溴铵(DBDAB)缓蚀的盐酸介质中的腐蚀动力学特征及苯扎溴铵与肉桂醛(CA)在盐酸介质中对Fe腐蚀的协同缓蚀作用,导出了腐蚀速度方程及有关的动力学参数并应用吸附理论和共吸附模型解释了苯扎溴铵在铁表面的吸附行为,探讨了盐酸介质中DBDAB与CA协同缓蚀作用的特点和机理     

油气开采环境下管道的协同腐蚀及防护研究进展*

服役于高温高压 CO₂ / H₂S 环境下的管道腐蚀是油气田中急需解决的重要问题。CO₂、H₂S 及 Cl^- 是油气田管道中常见的腐蚀介质，其与温度、压力、pH值、含水率、流速等外界因素间的协同腐蚀作用会导致管道严重腐蚀，研究这些腐蚀介质与外界因素的协同腐蚀机制以及减缓管道腐蚀的措施有着重要的科学意义和经济价值。针对油气开采过程中金属管道的腐蚀问题，综述了 CO₂、H₂S 及 Cl^- 在协同腐蚀过程中起到的作用，讨论了温度、压力、pH 值、含水率及流速等实际工况条件下外界因素对腐蚀过程的影响。论述了现有管道腐蚀防护技术与工艺的特点：合金元素的掺杂可以改善腐蚀形貌，提高腐蚀产物层的致密性，等离子体扩渗与镀膜技术能够制备一层致密的保护层来吸收部分腐蚀介质并减缓腐蚀速率，缓蚀剂的添加可以减缓管道的阴极或阳极反应或形成减缓腐蚀速率的吸附层。最后展望了未来油气田管道防护技术的发展方向：为了有效地对油气开采环境下的管道进行保护，需要进一步研究腐蚀介质和外界因素间的协同腐蚀作用，模拟实际工况下的腐蚀环境， 对等离子体扩渗与镀膜技术、缓蚀剂等现有的防护技术进行系统的试验测试。     

双生磺酸盐表面活性剂的金属清洗性能

研究了双生磺酸盐表面活性剂的金属清洗性能。结果表明,双生磺酸盐表面活性剂在适宜的温度和时间下能够彻底清除金属表面的油污,性能优于传统表面活性剂。在复配体系中,与非离子表面活性剂协同效应显著,清洗力高于各单一组分,与其他表面活性剂也有较好的配伍性,对金属表面的腐蚀率几乎为零,并能抑制非离子表面活性剂体系的腐蚀性。     

面向腐蚀工程的人工神经网络应用设想

提出一种依靠模式识别的人工神经网络方法，研究各种影响因素的作用程度，并利用资源优化模型，分析对腐蚀具体过程贡献相对较大的因素，从而在适时视情维修过程中提出合理的建议，评价各种防护措施的保护效果，以便为新型材料的研制，改进和研究应用提供可靠的依据。