天然海水中高效缓蚀剂对碳钢缓蚀作用的研究

以锌盐、葡萄糖酸盐为主要缓蚀成分复配的适用于天然海水中碳钢的高效缓蚀剂，用失重法测定其缓蚀效率，并用电化学方法分析其缓蚀作用机理．结果表明：未预膜时缓蚀剂的临界浓度是280mg／L．此时对碳钢的缓蚀率为93．8％，试样表面光亮如初，没有局部腐蚀；预膜后缓蚀剂的临界浓度降为210mg／L，此时对碳钢的缓蚀率为93．1％．通过极化曲线分析可知该缓蚀剂是一种抑制阳极过程为主的混合型缓蚀剂．据交流阻抗谱图分析得到该缓蚀剂成膜反应分3个阶段：反应初期，缓蚀剂在电极表面初步吸附；反应中期，至浸泡48h时第一层缓蚀膜形成；反应后期，缓蚀膜向多层发展．     

油酸基咪唑啉缓蚀剂的合成与缓蚀性能

以油酸和二乙烯三胺为主要原料,合成了一种咪唑啉缓蚀剂。采用傅立叶红外变换光谱仪（FTIR）测量产品的红外光谱,分析官能团,推断分子结构;采用失重法、Tafel曲线外延法、电化学阻抗技术等对合成的缓蚀剂在模拟气田水环境中的缓蚀性能及缓蚀机理进行了研究。结果表明,合成缓蚀剂的红外光谱中含有较强的咪唑啉特征吸收峰,其氮原子上存在孤对电子,可与金属原子配位结合形成牢固的化学吸附层。缓蚀剂对Q235试样在模拟气田水环境中具有较强的缓蚀作用,当浓度仅为100mg·L^-1时缓蚀率即可达到85%左右,并随缓蚀剂浓度增大而增大。缓蚀剂分子在金属表面吸附并成膜,阻止侵蚀性的离子在金属表面吸附和氧原子的扩散,从而起到保护金属的作用,缓蚀剂为阳极型缓蚀剂。     

一种新型的咪唑啉类缓蚀剂CPA-1对N80钢在CO2环境下的缓蚀性能评价

目的考察一种新型的咪唑啉类缓蚀剂CPA-1对N80钢在CO_2环境下的缓蚀性能。方法通过失重法、电化学阻抗谱和极化曲线,研究了在不同温度下缓蚀率和缓蚀剂浓度之间的关系,利用扫描电子显微镜和扫描电化学显微镜对表面形貌进行了观察分析,根据等温吸附模型研究了咪唑啉缓蚀剂在N80钢表面的吸附类型。结果失重结果表明,缓蚀剂的缓蚀效率随浓度的增大而升高,当温度为40℃、缓蚀剂质量浓度为250 mg/L时,缓蚀率达到95%;温度升高至80℃时,缓蚀率下降至87%。电化学试验表明,咪唑啉类缓蚀剂对阴极和阳极反应均有抑制作用。表面形貌分析表明,缓蚀剂能有效改善金属表面的腐蚀程度。结论咪唑啉类缓蚀剂CPA-1属于混合型缓蚀剂,对N80钢具有较好的缓蚀性能。缓蚀机理为通过吸附方式在金属表面形成一层吸附膜抑制金属腐蚀,吸附方式遵循Langmuir吸附等温模型,物理吸附和化学吸附均会在金属表面发生。     

K2L-SAMs对碳钢在饱和CO2油田水中的缓蚀行为与量子化学研究

利用邻氧乙酸苯甲醛缩对氨基苯磺酸钾盐席夫碱(K2L)缓蚀剂在20#碳钢表面制备自组装单分子膜(SAMs),并通过电化学方法研究缓蚀剂自组装膜的最佳组装时间;采用电化学测试技术和表面分析技术研究K2L-SAMs对碳钢在饱和CO2油田水介质中的缓蚀行为;采用密度泛函理论分析缓蚀剂分子的前线轨道、Mulliken电荷和分子静电势。结果表明:缓蚀剂在碳钢表面自组装3 h后,可以形成稳定、致密的缓蚀膜;在碳钢表面形成的K2L-SAMs能有效抑制碳钢的阴极还原过程,最高缓蚀效率达87.55%;K2L的吸附行为符合Langmuir吸附等温式,吸附机理为典型的化学吸附。量子化学计算结果表明:羧基是K2L分子的主要吸附活性区域,能与碳钢表面铁原子作用形成稳定的配位键。     

一种含CO_2油井用缓蚀剂的作用机理研究

通过进行J55钢在含CO_2油井模拟工况环境中的腐蚀速率测试,辅以极化曲线、交流阻抗等原位电化学测试技术,研究了一种咪唑啉类缓蚀剂的缓蚀效果及缓蚀作用机理。结果表明:该缓蚀剂具有优良的缓蚀作用,当缓蚀剂添加浓度为100 mg/L时,J55钢的平均腐蚀速率仅为0.0225 mm/a。该缓蚀剂是阳极型缓蚀剂,在一定范围内随着缓蚀剂浓度的增加,表层膜覆盖率增加,腐蚀抑制性增强。随着浸泡时间的延长,缓蚀剂分子在基体表面形成良好的吸附膜,在浸泡的48 h内,缓蚀率一直维持在97.80%左右,说明此缓蚀剂有较好的持续缓蚀效果。     

异喹啉季铵盐缓蚀剂FIQ-C在盐酸中长效缓蚀机理的探讨

通过红外光谱、俄歇电子能谱及色－质联仪对吸附膜的检测分析，探讨了FIQ－C在10％盐酸中的长效缓蚀机理，解释了长效缓蚀原因，证明了在盐酸溶液中异喹啉季铵盐缓蚀剂FIQ－C降解的含氮有机物小分子是吸附成膜的主要成分，且不随时间而变化。     

膜的离子选择性与钼酸钠-磷酸氢二钠体系的协同缓蚀机理

<正> 七十年代以来,佐藤等人利用膜电位法研究水合氧化铁膜的离子选择性认为,缓蚀剂的缓蚀作用是由于使金属表面膜由阴离子选择性变为阳离子选择性。本文用膜电位法研究Na_2MoO_4,Na_2HPO_4缓蚀剂的吸附特性,探讨其协同缓蚀机理,提出双层协同缓蚀吸附模型。     

碳酸氢钠溶液中苯并三氮唑对A3钢缓蚀作用的研究

以往对缓蚀剂在腐蚀产物膜上的缓蚀作用研究的较少,本文通过设计预腐蚀实验,研究了缓蚀剂在含膜表面的缓蚀作用。在实验中用静态挂片法研究了苯并三氮唑（BTA）对A3钢在碳酸氲钠溶液中缓蚀作用,并通过极化曲线探讨其缓蚀作用的机理,用扫描电镜（SEM）观察形成的表面膜形态,用XRD分析钢的表面腐蚀产物层的组成。实验表明苯并三氮唑在碳酸氢钠溶液中对A3钢有一定的缓蚀作用,可能是在A3钢表面形成一层Fe—BTA吸附膜,对阳极反应和阴极反应起一定阻滞作用,该膜吸附在金属表面阻滞侵蚀性离子吸附从而起到缓蚀效果。     

3,5-二溴水杨醛-2-噻吩甲酰肼席夫碱缓蚀剂在油田水中对碳钢的缓蚀性能及分子动力学模拟

合成了一种新的席夫碱缓蚀剂3,5-二溴水杨醛-2-噻吩甲酰肼(L2),通过Tefel极化曲线、电化学阻抗、扫描电镜和分子动力学模拟方法研究了该缓蚀剂在模拟油田水中对碳钢的缓蚀效果,并探讨了其缓蚀机理和吸附行为。结果表明,L2在不同温度、H2S浓度、pH值和Cl-浓度条件下的模拟油田水中对碳钢均具有良好的缓蚀性能。分子动力学模拟结果表明,在水溶液中缓蚀剂L2分子可以稳定地平行吸附在金属表面,有效地将金属表面和水分子隔开,从而起到缓蚀作用,吸附方式为多位点化学吸附;同时L2形成的分子吸附膜可有效地抑制腐蚀离子(Cl-和H3O+)在吸附膜中的扩散,避免了金属表面与腐蚀介质接触而发生腐蚀,从而表现出良好的缓蚀性能。     

水溶性聚苯胺对铸铁的缓蚀作用

利用水溶性聚苯胺作为铸铁的缓蚀剂,采用全浸腐蚀失重法和扫描电子显微镜(SEM)研究了缓蚀剂在0.2mol/L硫酸溶液中对铸铁的缓蚀能力。结果表明,缓蚀率随缓蚀剂浓度的增加而升高,随浸泡时间的延长和温度的升高而降低。15℃和55℃时缓蚀剂在铸铁表面的吸附行为遵循Langmuir等温吸附线,吸附平衡常数分别为9.67和2.59。SEM观察结果表明,0.2 mol/L硫酸溶液中添加缓蚀剂对铸铁表面的腐蚀起到了良好的保护作用。     

Inhibitor effects of triazole derivatives on corrosion of mild steel in acidic media

Abstract

The inhibitive action of triazoles on the corrosion of mild steel has been studied through weight loss and various electrochemical techniques. Results obtained show that these organic compounds are very good inhibitors. Triazoles are able to reduce the corrosion of steel more effectively in 1M HCl than in 0·5M H₂ SO₄ . Potentiodynamic polarisation studies clearly reveal the type of inhibitor. Changes in impedance parameters (the charge transfer resistance R_t and the double layer capacitance C_dl ) are related to adsorption of triazoles on the metal surface, leading to the formation of a protective film which grows with increasing exposure time. The adsorption of these inhibitors on the mild steel surface in both acids obeys the Langmuir adsorption isotherm. The comparative study of corrosion inhibition of triazole derivatives indicates that the efficiency of the 4-aminotriazole is greater than that of the 4H-triazole.     

咪唑啉类化合物在HCl溶液中对碳钢的缓蚀机理分析

目的 研究咪唑啉（IM）及咪唑啉基脲（IU）在盐酸溶液中对碳钢的缓蚀性能。方法 采用静态失重法、电化学测试技术、表面形貌及官能团分析、热力学等温方程等方法,研究缓蚀剂在不同温度的盐酸溶液中对Q235碳钢的缓蚀性能和吸附规律。结果 在静态失重试验中,室温下,随着IM、IU缓蚀剂的加入,碳钢的腐蚀速率从12.54 mg/(cm2?h)分别降低到5.132、0.145 mg/(cm2?h),IM、IU的缓蚀率分别为59.1%和98.9%。随着温度的升高,缓蚀效率略有下降。极化曲线试验表明,增加两种缓蚀剂的浓度,腐蚀电位负移,阳极电流密度下降明显。交流阻抗的测试显示,随着两种缓蚀剂浓度的增大,拟合参数Rct增大、Cdl减小,证明缓蚀剂在金属表面取代了水,并吸附成膜。研究等温吸附模型发现,两种缓蚀剂分子在碳钢表面的吸附符合Langmuir等温吸附方程,且根据SEM及XPS分析,证明缓蚀剂分子通过N原子与金属形成共价键,在金属表面吸附成膜。结论 咪唑啉和咪唑啉基脲对碳钢均具有缓蚀效果,且咪唑啉基脲的缓蚀效果更优异。两种缓蚀剂均属于混合型缓蚀剂,且以抑制阴极腐蚀反应速率为主。两种咪唑啉化合物在碳钢表面的吸附过程为自发放热过程,其吸附规律遵循Langmuir吸附等温模型,属于单分子层吸附。     

Inhibition of mild steel corrosion in presence of fatty acid imidazolines in hydrochloric acid

The corrosive behavior of mild steel in 1M HCl solutions containing selected imidazolines of fatty acids with C₇-C₁₇ was investigated using weight-loss method, potentiodynamic polarization technique and scanning elecron microscopy. The results obtained revealed that all the studied imidazolines are effective in reducing corrosion of mild steel in HCl media. The adsorption of the inhibitors on the mild steel surface obeys Langmuir’s adsorption isotherm. The thermodynamic parameters of adsorption deduced reveal a strong interaction and spontaneous adsorption of inhibitors on the mild steel surface. The influence of inhibitor concentration, solution temperature, immersion time and acid concentration on the corrosion of mild steel has also been investigated. Scanning electron microscopy(SEM) of mild steels samples is performed to show adsorption of inhibitors on metal surface. Potentiodynamic polarization data showed that the compounds studied are mixed type inhibitors in the acid solution. Original Russian Text ? M.A. Quaraishi, M.Z.A. Rafiquee, Nidhi Saxena, Sadaf Khan, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 1, pp. 99–106.     

钨系水处理剂及其缓蚀机理的研究

研究了钨系水处理剂复合配方对碳钢在含Cl~-及SO_4~(2-)水中的缓蚀作用,筛选出最佳复配方案。根据电化学测试和XPS分析结果探讨了钨系水处理剂的缓蚀机理。     

Experimental evaluation of quinolinium and isoquinolinium derivatives as corrosion inhibitors of mild steel in 0.5 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript> solution

The 1-methylquinolinium iodide (I) Qui⁺, I^– and 2-methylisoquinolinium iodide isoQui⁺, I^– were investigated as a corrosion inhibitors for mild steel in sulfuric acid using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicated that the corrosion inhibition efficiency and extent of surface coverage were increased with increase in inhibitors concentrations. Polarization curves revealed that both inhibitors acted as a mixed-type inhibitor. The thermodynamic parameters were evaluated for corrosion inhibition process. The adsorption of both inhibitors on mild steel surface obeyed Langmuir adsorption isotherm.     

Adsorption and inhibitive properties of some new Mannich bases of Isatin derivatives on corrosion of mild steel in acidic media

Adsorption of four derivatives of piperidinylmethylindoline-2-one on mild steel surface in 1 M HCl solution and its corrosion inhibition properties has been studied by a series of techniques, such as polarization, electrochemical impedance spectroscopy (EIS), weight loss and quantum chemical calculation methods. The values of activation energy (E_a) for mild steel corrosion and various thermodynamic parameters were calculated and discussed. Potentiodynamic polarization measurements showed that all inhibitors are mixed type. The degree of surface coverage was determined by using weight loss measurements and it was found that adsorption process of studied inhibitors on mild steel surface obeys Langmuir adsorption isotherm.     

吡啶嗡离子衍生物的缓蚀作用及其吸附模型

用线性极化曲线法研究了N 癸基吡啶溴化铵 (DP) /N 癸基 3 羟基吡啶溴化铵 (D3OP)和N 癸基 3 羧基吡啶溴化铵 (D3CP)在 5 %氨基磺酸中对铁的缓蚀作用及其吸附模型。结果表明 :它们对 5 %氨基磺酸中的铁具有良好的缓蚀作用 ,在吡啶环上引入合适的取代基能提高吡啶嗡离子的缓蚀效果。它们在铁表面的吸附主要为物理吸附 ,其吸附遵循Langmuir吸附等温式 ;随着温度和使用浓度的提高 ,其缓蚀性能加强 ;三种缓蚀剂缓蚀能力大小为D3CP >D3OP >DP。     

Effect of substituents on the inhibitive properties of newly synthesized 5-benzoyl-4-methyl-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one derivatives against mild steel corrosion in an acidic medium

Inhibition performance of three newly synthesized 1,5-benzodiazepine derivatives with 4-methoxybenzoyl (methoxyBBD), 3-methylbenzoyl (methylBBD), and 2-chlorobenzoyl (chloroBBD) groups was investigated against mild steel corrosion in 1 M hydrochloric acid. The potentiodynamic polarization, electrochemical impedance spectroscopy, and adsorption isotherms were used for characterization of the corrosion processes. Surface morphology was studied by scanning electron microscope (SEM). Quantum chemical calculations were carried out to establish the active sites of the inhibitors. The results show that the inhibitors inhibit mild steel corrosion and their inhibition efficiencies (IE) increase with the increase in concentration. The methoxyBBD shows a higher inhibiting effect with IE of 89.13% at 10⁻³ M, followed by methylBBD. All three inhibitors act as mixed-type inhibitors with predominant control of cathodic reaction for chloroBBD and their adsorption obeys Langmuir isotherm. The SEM analysis confirms the inhibitors' adsorption on the mild steel surface. The active sites of the inhibitors were effectively established using the density functional theory method on the basis of natural atomic charge, highest occupied molecular orbital, and the lowest unoccupied molecular orbital frontier molecular orbitals. The experimental and quantum results prove the inhibition performance trend of the inhibitors as follows: methoxyBBD > methylBBD > chloroBBD.     

Investigation of some Schiff base compounds containing disulfide bond as HCl corrosion inhibitors for mild steel

The inhibition performance of three Schiff bases containing disulfide bond as corrosion inhibitors for mild steel in 2.0 M HCl has been investigated by weight loss measurements, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization study showed that all the inhibitors are mixed type. The adsorption of inhibitors on mild steel surface was found to follow Langmuir adsorption isotherm and the adsorption isotherm parameters (K_ads, ΔG_ads) were determined. Quantum chemical calculations were further applied to reveal the adsorption structure and explain the experimental results. Some samples of mild steel were examined by SEM.     

Inhibiting effects of some mercapto-triazole derivatives on the corrosion of mild steel in 1.0 M HCl medium

The effect of some mercapto-triazole derivatives synthesized in the laboratory containing different hetero atoms and substituents in the organic structures on the corrosion and hydrogen permeation of mild steel in 1.0 M HCl was investigated by weight loss and various electrochemical techniques. Results obtained reveal that all the mercapto-triazole derivatives perform excellently as corrosion inhibitors for mild steel in 1.0 M HCl. Potentiodynamic polarization studies have shown that all these compounds suppress both the anodic and cathodic process and they behave as mixed-type inhibitors. Double layer capacitance and charge transfer resistance values were derived from Nyquist plots obtained from AC impedance studies. Changes in impedance parameters are indicative of the adsorption of these compounds on the metal surface. The inhibition efficiency mainly depends on the nature of the investigated compounds. The values of the inhibition efficiency calculated from these techniques are in reasonably good agreement. The extent of reduction of hydrogen permeation current through mild steel surface was studied by the hydrogen electropermeation technique. The adsorption of these compounds on mild steel surface is found to obey Langmuir adsorption isotherm. The free energy of adsorption for inhibiting process was determined on the basis of Langmuir adsorption isotherm.