2种四唑衍生物缓蚀剂在碱性介质中对铜的缓蚀性能和吸附行为

有机缓蚀剂能在金属表面发生吸附而降低金属的腐蚀速率,但目前对其在金属表面的吸附机理仍不十分清楚.合成了胍基四唑(GT)和1-(对甲基)苯基-5-巯基-1,2,3,4-四氮唑(MMT)2种缓蚀剂,用失重法和电化学法研究了2种缓蚀剂在5%NaHCO_3碱性介质中对铜的缓蚀性能和吸附行为.结果表明:MMT和GT属于阳极型缓蚀剂,对铜均有很好的缓蚀性能,且MMT的缓蚀效率大于GT;MMT和GT均在浓度为50 mg/L时缓蚀效率最大(90%以上);30～60℃时2种缓蚀剂的缓蚀性能随温度的升高而降低;2种缓蚀荆在铜表面的吸附都服从Langmuir吸附等温式,属于物理吸附.     

聚合型咪唑啉缓蚀剂的合成与性能

为提高咪唑啉缓蚀剂的水溶性及缓蚀效率,以己二酸与二乙烯三胺为原料合成了带酰胺和咪唑啉基团的聚合型缓蚀剂PIM,以羟乙基乙二胺为原料合成了常见的非聚合型缓蚀剂UPIM;采用红外光谱和质谱测试了2种缓蚀剂的结构及分子量;采用交流阻抗法分析了2种缓蚀剂在N80钢表面的吸附性质,并拟合了表面覆盖率和时间的关系曲线;采用Tafel极化曲线法测试了不同浓度缓蚀剂对N80钢的缓蚀性能.结果表明:N80钢在含50mg/LHM的0.5 mol/L H2SO4溶液中浸泡6 min后,覆盖率达到85.02％,高于UPIM;当0.5 mol/L H2SO4溶液中聚合型缓蚀剂PIM浓度为400 mg/L时,缓蚀率最高可达96.7％,明显高于缓蚀剂UPIM的;经过较长时间腐蚀后,聚合型缓蚀剂PIM在金属表面的吸附稳定性优于UPIM的.     

油溶性噻二唑衍生物的合成及其缓蚀性能研究

合成了5-苯基-2-氨基-1,3,4-噻二唑(PATD)和2,5-二苯基-1,3,4-噻二唑(DPTD)两种噻二唑衍生物。通过电化学技术研究了这两种物质在50mg/L S-乙醇溶液中对银电极的影响。结果表明这两种油溶性化合物对银产生明显的缓蚀作用,PATD和DPTD的缓蚀效率分别为93.0%和90.8%。采用金相显微镜和表面接触角观察了银片在未添加和添加缓蚀剂的溶液中腐蚀前后的表面形貌。结果表明:通过金相显微镜可以看到,两种缓蚀剂在银片表面形成了保护膜,有效地抑制了银片的腐蚀;PATD和DPTD在银片表面的接触角分别为84.2°和100°,接触角明显增大,也说明缓蚀剂吸附到了金属的表面,形成了疏水膜。两种缓蚀剂吸附到银表面遵循Langmuir吸附等温方程,计算得PATD和DPTD的ΔG0ad分别为-34.3kJ/mol和-36.7kJ/mol,吸附属于以化学吸附为主的混合型吸附。     

邻菲罗啉及其衍生物对盐酸中铜的缓蚀性能

邻菲罗啉(PHEN)及其衍生物可有效抑制金属及其合金在酸性介质中的腐蚀,但目前还未见其对铜材缓蚀的报道。采用失重法及扫描电镜(SEM)研究了PHEN及其衍生物2-苯基-1H-咪唑[4,5-f][1,10]邻菲罗啉(PIPH)这2种有机缓蚀剂在1 mol/L HCl溶液中对铜的缓蚀作用,并对其缓蚀机理进行探讨。结果表明:当缓蚀剂浓度为1.0 mmol/L、温度为30℃,吸附成膜时间4 h,2种缓蚀剂在1 mol/L HCl溶液中的缓蚀效率均达最大值,PHEN和PIPH对铜的缓蚀效率可分别达到96.4%和99.7%;2种缓蚀剂在铜表面的吸附均符合Langmuir吸附模型,且均为化学吸附。     

噻二唑型缓蚀剂对铜片的缓蚀性能研究

采用增重法和金相显微技术研究了含硫油样对铜片的腐蚀行为,以及噻二唑类缓蚀剂(用A表示)在含硫量为50μg/g的模拟油样中对铜的缓蚀性能。结果表明,缓蚀剂A对铜片具有良好的缓蚀效果,且随着浓度的增加,缓蚀效率提高。当缓蚀剂浓度为25.0μg/g时,缓蚀效率达到86.45%。经吸附等温线拟合可知,缓蚀剂A在铜片表面的吸附遵循Langmuir吸附等温方程,属于化学吸附。     

3-(苯胺基甲基)-苯并噻唑-2-硫酮的缓蚀性能及吸附作用

为了研究缓蚀剂分子与金属表面的吸附作用,以2-巯基苯并噻唑、甲醛和苯胺为原料在微波辐照下合成了3-(苯胺基甲基)-苯并噻唑-2-硫酮(PAMMOA),利用失重法和动电位极化曲线对合成缓蚀剂的缓蚀性能进行了测试,并利用分子动力学模拟和量子化学计算方法对其在Fe表面的吸附作用进行了探讨。结果表明:该缓蚀剂能够有效抑制饱和CO2环境下、模拟腐蚀介质中N80钢的腐蚀,属于混合型缓蚀剂;其分子中最高占据轨道(HOMO)的电荷主要分布在巯基苯并噻唑环上,同时分子中的苯胺基上也有一定的电荷分布,而其最低空轨道(LUMO)的电荷主要分布在巯基苯并噻唑环上,当其分子与Fe金属表面发生吸附时,分子中的巯基苯并噻唑环和苯胺基在同一平面上,并平行吸附于Fe表面。     

ZS曼尼希碱缓蚀剂的制备与性能

为了解决在油气田酸化过程中酸液对地面管路及井筒管壁造成严重腐蚀的问题,合成了一种新型的噻唑类曼尼希碱缓蚀剂来保护金属。通过静态失重法、电化学方法和分子动力学模拟方法研究了该缓蚀剂在15%盐酸腐蚀介质中对N80钢的缓蚀性能。静态失重法表明:在加入1.0%(质量分数)优选配方合成的缓蚀剂ZS的腐蚀介质中N80钢的腐蚀速率为0.412 9 g/(m~2·h),远优于SY 5405-1996中的一级标准。电化学测试表明:该缓蚀剂是以抑制阳极反应为主的混合型缓蚀剂,其在N80钢表面上的吸附行为服从Langmuir吸附等温式,说明缓蚀剂ZS在N80钢上形成了单分子层吸附。分子动力学模拟结果表明:在介质中缓蚀剂分子可以稳定地吸附在金属表面,并有效地将金属表面和腐蚀介质隔开,从而起到缓蚀作用。     

盐酸介质中咪唑离子液体对铜的缓蚀作用

以1-甲基咪唑、1,4-丁烷磺内酯和浓硫酸为原料,用乙醚洗涤合成了1-甲基-3-(4-硫酸基丁基)咪唑硫酸盐(4-BMIM)缓蚀剂。采用动电位极化和交流阻抗技术研究了4-BMIM在5%HCl溶液中对铜的缓蚀性能及作用机理。实验结果表明:缓蚀效率随着缓蚀剂浓度的增加先增大后降低,当浓度为0.03mol/L时,缓蚀效率最高;同一浓度下,随着温度的升高缓蚀效率降低。动电位极化表明咪唑离子的加入对铜的阴、阳极腐蚀过程均有抑制作用,是混合型缓蚀剂。热力学计算结果表明咪唑离子液体吸附在铜表面,其吸附机制为自发进行的物理吸附,并且在铜/溶液界面的吸附遵循Langmuir吸附等温式。     

2-氨基苯并咪唑缩对甲基苯甲醛席夫碱的合成及缓蚀性能

采用静态失重、极化曲线、交流阻抗(EIS)方法测试席夫碱自组装膜在3.5％(质量分数)NaCl溶液中对铜的缓蚀作用,考察了浓度和时间两个因素.结果表明,当浓度为15 mmol/L,组装时间为14 h时,合成的缓蚀剂缓蚀性能较好,缓蚀率可达99.89％.表面形貌分析结果表明,席夫碱化合物在铜表面形成簇状物质.拉曼光谱分析结果表明,席夫碱通过咪唑环和C=N键垂直吸附于金属表面.光学接触角测量结果表明,缓蚀剂表面不易被浸润,疏水性较好.     

Ti-6Al-4V钛合金在氢氟酸-硝酸体系下的缓蚀行为及机理

本工作利用失重法、扫描电子显微镜(SEM)、金相显微镜和电化学方法研究金莲橙OOO、铜铁灵、硫脲对钛合金在氢氟酸-硝酸混合溶液中的缓蚀作用,并通过接触角、表面张力法、红外光吸收谱(FTIR)研究缓蚀过程与机理。失重法、SEM测试和电化学方法都表明,当酸洗液中的氢氟酸与硝酸浓度比为1∶37.5时,三种缓蚀剂缓蚀效果排序为:金莲橙OOO铜铁灵硫脲。金莲橙OOO浓度越高,钛合金表面呈现的疏水性越强,缓蚀效果越好。表面张力随缓蚀剂浓度的增加呈线性减小趋势,达到临界胶束浓度后,钛合金表面的缓蚀剂分子吸附速率达到平衡,表面张力变化逐渐稳定,此时吸附效果最好。金莲橙OOO属于综合吸附膜型缓蚀剂,通过多中心吸附的方式生成大面积疏水膜,其缓蚀效果最好且随着浓度的增加而增强,在最佳浓度1.2 mmol/L下可保证钛合金的腐蚀失重在5.5 mg/cm~2左右,缓蚀率为79%。     

Crystal growth study using combination of molecular dynamics and Monte Carlo methods

Molecular dynamics method although provides details of energies of the system as a function of time, is not suited to simulate the processes involving activation processes. Therefore, we attempted to combine the molecular dynamics and Monte Carlo methods. Using molecular dynamics, the energies of the system were calculated which were subsequently combined with Monte Carlo method using random numbers, epitaxial growth of (111) plane of copper, silver, and gold. While surface adsorption and surface diffusion for copper, silver, and gold were simulated by use of molecular dynamics method, the relation between the growth rate of thin films and the packing density of atoms were obtained using Monte Carlo simulation. Thus, by combining the results of the molecular dynamics method and the Monte Carlo method the growth process of thin films at elevated temperatures were obtained, which is too tedious to be calculated by molecular dynamics alone.     

Computer simulation of surface diffusion of copper, silver and gold

The binding energies to copper, silver and gold (111) surfaces of self-atom clusters have been calculated. The activation energies of motion of these ad-atom clusters, vacancies and divacancies on copper, silver and gold (111) surface, and of the conversion of ad-atom clusters on (111) and (100) have been calculated by use ofn-body embedded atom potentials and molecular dynamics.     

A green and effective corrosion inhibitor of functionalized carbon dots

In this work, a green and effective corrosion inhibitor of functionalized carbon dots (FCDs) was synthesized by the conjugation of imidazole and citric acid carbon dots (CA-CDs). The corrosion inhibition behavior of FCDs for Q235 steel in 1 M HCl solution was systematically investigated by electrochemical analysis, corrosion morphology and adsorption isotherm. The electrochemical results implied that the as-prepared FCDs inhibitor could effectively suppress the corrosion of Q235 steel in 1 M HCl solution. At the same time, the inhibition efficiency of steel in 1 M HCl solution was more than 90% when the inhibitor concentration exceeded 100 mg/L. This excellent property was attributed to the coverage of adsorption film on the steel surface, which conformed to the Langmuir adsorption model. In addition, the analysis of adsorption isotherm displayed that the adsorption mechanism was the physicochemical interaction at the steel/solution interface.     

Computational and electrochemical studies of some amino acid compounds as corrosion inhibitors for mild steel in hydrochloric acid solution

The corrosion inhibition behaviour of four selected amino acid compounds, namely l-cysteine, l-histidine, l-tryptophan and l-serine on mild steel surface in deaerated 1 M HCl solution were studied electrochemically by Tafel polarization and electrochemical impedance spectroscopy methods and computationally by the quantum chemical calculation and molecular dynamics simulation. Electrochemical results show that these amino acid compounds inhibit the corrosion of mild steel in 1 M HCl solution significantly. The order of inhibition efficiency of these inhibitors follows the sequence: l-tryptophan > l-histidine > l-cysteine > l-serine. The quantum chemical calculations were performed to characterize the electronic parameters which are associated with inhibition efficiency. The molecular dynamics simulations were applied to find the equilibrium adsorption configurations and calculate the interaction energy between inhibitors and iron surface. Results obtained from Tafel and impedance methods are in good agreement. The electrochemical experimental results are supported by the theoretical data.     

Surface Protection and Morphological Study of Copper by Green Corrosion Inhibitor: 8QSC in HNO<Subscript>3</Subscript> Medium

The inhibition performance and surface protection of green corrosion inhibitor 8-quinoline sulphonyl chloride (8QSC) on copper (Cu) was evaluated by chemical (weight loss) method in 0.5, 1.0 and 2.0 M HNO₃ solutions and by electrochemical methods such as potentiodynamic polarization (PDP), AC-impedance spectroscopy (AC-IS) and linear polarization resistance in 1.0 M HNO₃ solution at room temperature. Both chemical and electrochemical techniques showed that 8QSC is an efficient green corrosion inhibitor for copper and the efficiency reached 90.4% by weight loss method and 88.4% by AC-IS method at optimum concentration of (300 ppm) 8QSC. The adsorption behavior of 8QSC on copper metal in acid medium obeyed the Langmuir isotherm. The thermodynamic parameters of the adsorption processes were calculated and discussed. AC-IS technique exhibits one capacitive loop, indicating that the corrosion reaction was controlled by charge transfer process. The PDP curves revealed that 8QSC acts as a mixed-type inhibitor. Protective layer of 8QSC on copper surface was examined by SEM, AFM and FT-IR techniques. The experimental results corroborated with results obtained from theoretical DFT studies.     

铜表面硅烷-稀土掺杂膜的制备及缓蚀性能

运用分子自组装技术在铜片表面组装γ-巯丙基三甲氧基硅烷(MPTS)与稀土的掺杂膜。用原子力显微镜(AFM)观察了铜表面成膜过程,用金相显微镜观察铜片在0.5mol/L盐酸溶液中腐蚀72h后的表面形貌,运用电化学测量法对其防腐蚀性能进行评价。结果表明,硅烷-稀土掺杂膜对铜的缓蚀效率较单一的硅烷膜有明显提高,稀土浓度及组装时间对掺杂膜抗腐蚀性能有一定影响。经过极化曲线和交流阻抗的测定,确定硅烷-稀土掺杂膜的最佳组装条件为:LaCl3质量浓度为10g/L,组装30min,缓蚀率达93%。     

双稀土处理液对H62黄铜成膜耐蚀性能的影响

为了提高H62黄铜合金的表面性能,通过正交试验获得了最佳锅、钵双稀土处理液配方。利用硝酸点滴、中性盐雾试验评价了H62黄铜合金钝化膜的耐蚀性能,通过电子探针(EPMA)观测了其表面形态结构及元素分布,利用电化学方法表征了 H62黄铜表面钝化膜在3.5%NaCl溶液中的缓蚀行为,采用XRD对H62黄铜表面钝化膜的成分进行了检测。结果表明:H62黄铜合金由镉、钵双稀土处理液钝化成膜的主要成分为Cu2O,CeO2,La(OH)3,Ce(OH)4;致密的钝化膜耐硝酸点滴时间达到21.98s,在3.5%NaCl溶液自腐蚀电位增加,腐蚀电流降低,腐蚀速度明显降低,耐蚀性能增加,耐中性盐雾性能明显优于鋪单一稀土处理液。     

Corrosion inhibition and adsorption behavior of 2-((dehydroabietylamine)methyl)-6-methoxyphenol on mild steel surface in seawater

The inhibition effect of a Dehydroabietylamine Schiff base derivative, namely 2-((dehydroabietylamine)methyl)-6-methoxyphenol (DMP) against mild steel corrosion in seawater was evaluated using weight loss and electrochemical techniques (potentiodynamic polarization and electrochemical impedance). The experimental results showed that DMP is a good corrosion inhibitor and the inhibition efficiency increased with the increase of DMP concentration, while the adsorption followed the Langmuir isotherm. X-ray photoelectron spectroscopy, scanning electron microscopy, theoretical calculation of electronic density, molecular electrostatic potential and molecular dynamics were carried out to establish mechanism of corrosion inhibition for mild steel with DMP in seawater medium. The inhibition action of the compound was assumed to occur via adsorption on the steel surface through the active centers in the molecule. The corrosion inhibition is due to the formation of a chemisorbed film on the steel surface.     

氨基磺酸中肉桂醛缩甲胺席夫碱对Q235钢的缓蚀吸附行为

为进一步研究肉桂醛缩甲胺席夫碱在氨基磺酸介质中对碳钢的腐蚀机理,利用极化曲线、原子力显微镜、X射线光电子能谱仪和量子化学计算,研究了5%氨基磺酸介质中肉桂醛缩甲胺席夫碱在Q235钢表面的缓蚀吸附行为。结果表明:在70℃、5%氨基磺酸介质中,肉桂醛缩甲胺在Q235钢表面的吸附行为符合Langmuir吸附等温式,是一种混合型缓蚀剂,且该缓蚀剂在Q235钢表面的吸附存在不均匀性;Q235钢在氨基磺酸溶液中的腐蚀产物主要为Fe SO4、Fe S,缓蚀剂的吸附抑制了Fe S的生成。