盐酸溶液中3-(4-苯亚甲基-)氨基-1,2,4-三氮唑对5052铝合金的缓蚀性能

为研制一种高效且性能优异的铝合金用酸洗缓蚀剂,以苯甲醛和3-氨基-1,2,4-三氮唑为原料合成了席夫碱3-(4-苯亚甲基-)氨基-1,2,4-三氮唑。通过核磁共振表征了其结构;采用静态失重法、动电位极化法、电化学阻抗法和扫描电镜等研究了其在1 mol/L HCl溶液中对5052铝合金的缓蚀性能。结果表明:所合成的3-(4-苯亚甲基-)氨基-1,2,4-三氮唑在1 mol/L HCl溶液中对5052铝合金具有良好的缓蚀作用,在一定浓度范围内,其缓蚀效率随缓蚀剂浓度的增加而增大,缓蚀剂浓度为5 mmol/L时,缓蚀效率高达95.1%;该缓蚀剂为阴极抑制型缓蚀剂,在5052铝合金表面上的吸附符合Lagmuir吸附,且以化学吸附为主。     

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。     

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.     

不同链长的吡啶基离子液体在盐酸中对N80钢的缓蚀行为

为获得较咪唑啉类更低浓度、更高效率的离子液体缓蚀剂,通过失重测试、电化学测试、扫描电子显微镜(SEM)和原子力显微镜(AFM)等研究了不同浓度的吡啶基离子液体B4MePyBr、O4MePyBr和硫酸二甲酯吡啶季铵盐缓蚀剂在盐酸中对N80钢的缓蚀行为.失重试验表明,3种缓蚀剂的缓蚀效率均随着添加浓度的增加而增加,25℃下当O4MePyBr添加浓度为10 mmol/L时,缓蚀效率能达到90％以上,且3种缓蚀剂的最大缓蚀效率排序为O4MePyBr＞B4MePyBr＞硫酸二甲酯吡啶季铵盐;电化学测试表明,3种缓蚀剂均为混合型缓蚀剂;表面形貌测试表明,缓蚀剂能够有效地吸附在碳钢表面,吸附膜层非常紧密;3种缓蚀剂在碳钢表面的吸附均遵循Langmuir吸附等温方程.     

N-烷基苯并咪唑酸化缓蚀剂的合成及性能

苯并咪唑是一类环境友好的缓蚀剂,将其衍生物用作油气田酸化缓蚀剂的报道较少。通过烷基化反应在2-甲基苯并咪唑和2-乙基苯并咪唑的1-氮原子上分别引入十二烷基和十六烷基,合成了4种N-烷基苯并咪唑,并以其为主剂制成缓蚀剂,用静态失重法和动电位扫描极化曲线对4种复配缓蚀剂在盐酸溶液中的缓蚀性能进行了评价。结果表明:适当延长1位烷基碳链,有助于提高苯并咪唑衍生物的缓蚀能力;合成的4种N-烷基苯并咪唑中,以N-十六烷基-2-乙基苯并咪唑为主剂制成缓蚀剂d的缓蚀性能最好;在60℃,15%HCl中,N80钢的腐蚀速率随缓蚀剂d用量的增大而减小,其用量为1.0%时,N80钢腐蚀速率为1.73 g/(m2.h),优于酸化缓蚀剂一级品的要求;该缓蚀剂是以抑制阴极过程为主的混合型缓蚀剂,在浓度大于20%的盐酸或温度高于70℃的环境中使用时缓蚀效果不佳。     

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。     

马齿苋提取液对盐酸溶液中Q235碳钢的缓蚀作用

为了开发新型环境友好的天然缓蚀剂,采用索氏提取法提取马齿苋中的有效成分,采用失重法、动电位极化曲线和交流阻抗研究了不同浓度马齿苋提取液在1.0 mol/L盐酸溶液中对Q235碳钢的缓蚀作用及机理。结果表明:马齿苋提取液在盐酸介质中对碳钢具有良好的缓蚀效果,缓蚀效率随缓蚀剂浓度增大而升高,30℃下当提取液的浓度达到0.16 g/m L时,其缓蚀效率可达91%以上;随温度升高,马齿苋提取液对碳钢的缓蚀效率降低;马齿苋提取液是一种抑制阴阳极反应的混合型缓蚀剂,有效成分吸附在碳钢表面形成一层保护膜,吸附过程遵循Langmuir等温方程式,其在碳钢表面的吸附属于自发过程,是以化学吸附为主的物理和化学吸附共同作用的过程。     

一种含硫杂环双席夫碱化合物在硫酸介质中对Q235碳钢的缓蚀作用

目前对于双席夫碱化合物用作碳钢缓蚀剂的研究报道较少。合成了一种含硫杂环双席夫碱化合物:双噻吩-2-甲醛缩邻苯二胺(DTCPA),采用静态失重法、动电位极化曲线和交流阻抗谱测试考察了其在0.5 mol/L H_2SO_4溶液中对Q235碳钢的缓蚀作用。结果表明,DTCPA对碳钢具有良好的缓蚀效果,随着DTCPA浓度的增加腐蚀速率下降,缓蚀效率不断提高;然而,随着温度升高,腐蚀速率加快,缓蚀效率下降。DTCPA在硫酸介质中对碳钢的缓蚀作用属于一种抑制阴阳两极反应的混合型缓蚀剂,在碳钢表面形成了一层致密的保护膜,有效阻挡了硫酸对碳钢的腐蚀,其在碳钢表面的吸附遵循Langmuir吸附等温式。     

3种双咪唑啉季铵盐对Q235钢在盐酸溶液中的缓蚀性能及吸附行为

咪唑啉类缓蚀剂缓蚀性能优异,应用前景广阔。目前对双咪唑啉缓蚀剂在金属表面吸附行为的研究未见报道。合成了3种双咪唑啉季铵盐CABI,BABI,SABI,用红外光谱表征了其结构,并用失重法和电化学方法研究了其在1mol/LHCl溶液中对Q235钢的缓蚀性能和吸附行为。结果表明:3种双咪唑啉季铵盐在1mol/LHCl介质中对Q235钢都具有良好的缓蚀性能,且用量少;较高温度(50～80℃)下的缓蚀效率达90%以上,其缓蚀能力大小顺序为CABI>BABI>SABI,均属于阴极型缓蚀剂;在Q235钢表面的吸附过程为放热过程,吸附行为服从Langmuir吸附等温式,主要为化学吸附。     

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.     

The inhibition of 4-(2′-amino-5′-methylphenylazo) antipyrine on corrosion of mild steel in HCl solution

The effect of 4-(2′-amino-5′-methylphenylazo) antipyrine (AMPA) on the corrosion of mild steel in a 2 M HCl solution was studied using weight loss and potentiodynamic polarization techniques. All of the data reveal that AMPA acts as an inhibitor in the acid environment; furthermore, polarization data show that the compound behaves as a mixed-type inhibitor. It was found that the inhibition efficiency increases with an increase in AMPA concentration but decreases with an increase in temperature. Flory–Huggins adsorption isotherm and El Awady thermodynamic–kinetic model fit the experimental data of the studied compound. Thermodynamic parameters for corrosion and adsorption processes were obtained from experimental data of the temperature studies.     

Inhibitive effect of synthesized 2-(3-pyridyl)-3,4-dihydro-4-quinazolinone as a corrosion inhibitor for mild steel in hydrochloric acid

In this study, the inhibitive effect of synthesized 2-(3-pyridyl)-3,4-dihydro-4-quinazolinone (PDQ) as a new corrosion inhibitor for mild steel in 0.1 M hydrochloric acid media is investigated employing potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. The results show PDQ reduces anodic dissolution, retards the hydrogen evolution reaction and its adsorption obeys the Langmuir's adsorption isotherm. By increase in temperature, corrosion current density increases, however, its increase is lower in the presence of PDQ. By increase in temperature from 25 °C to 45 °C the inhibition efficiency decreases from 93% to 83% in solution containing 200 ppm inhibitor. Thermodynamic adsorption parameters show that PDQ is absorbed by a spontaneous exothermic process and its adsorption mechanism is combination of physical and chemical style.     

两种酰胺醇类抗生素过期药在20%醋酸中对A3钢的缓蚀效果和机理

过期药对金属缓蚀作用的研究为其回收再利用提供了一个较好的方向,具有一定的环境保护意义。通过失重法、电化学法、形貌分析等方法研究了2种酰胺醇类抗生素过期药在20%醋酸中对A3钢的缓蚀和机理。结果表明:2种药物都是随着浓度的增加缓蚀率提高,并且氯霉素比甲砜霉素缓蚀效果好。动电位极化曲线表明氯霉素和甲砜霉素均属于混合型缓蚀剂,当浓度达到2.0×10~(-4)mol/L时,其对A3钢的缓蚀效率分别为57.0%和55.3%。这2种缓蚀剂的吸附行为均是单分子层物理吸附。     

Green approach to corrosion inhibition of mild steel in two acidic solutions by the extract of Punica granatum peel and main constituents

The effect of the extract of Punica granatum (PG) and their main constituents involve ellagic acid (EA) and tannic acid (TA), as mild steel corrosion inhibitor in 2 M HCl and 1 M H₂SO₄ solutions was investigated by weight loss measurements. The results obtained from the weight loss measurements show that the inhibition efficiency of TA even in high concentration is very low. Thus, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) investigations were used for different concentrations of PG and EA and best concentration of TA. Potentiodynamic polarization curves indicated that PG and EA behave as mixed-type inhibitors. EIS measurements show an increase of the transfer resistance with increasing inhibitor concentration. The temperature effect on the corrosion behavior of steel without and with the PG extract was studied. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm.     

Effect of tannic acid on corrosion behavior of carbon steel in NaCl solution

Corrosion behavior of unrusted Q235 carbon steel was investigated in 3.5% NaCl solutions with 1–5 wt%tannic acid addition, using electrochemical methods including electrochemical impedance spectra(EIS),potentiodynamic polarization and scanning vibrating electrode technique(SVET) combined with surface analysis. Results show that the corrosion rate decreases with increasing tannic acid concentration. As compared with tannic acid-free solution, 1% tannic acid does not provide inhibition effect during the whole immersion, while inhibition effect is observed for 3% tannic acid after 8 h and for 5% tannic acid after 4 h. The inhibition efficiency by weight loss measurements(áw) for 1%, 3%, and 5% tannic is around-17.2%, 40.3%, and 51.5%, respectively. Corrosion of unrusted carbon steel in the presence of tannic acid is attributed to the joint effect of tannic acid adsorption and pH decrease. Formation of ferric-tannates is verified by X-ray photoelectron spectroscopy(XPS) and Raman spectra. The reaction mechanism between tannic acid and unrusted carbon steel is proposed.     

吐温-60对钢在H2SO4中的缓蚀性能

用失重法研究了非离子表面活性剂吐温-60对冷轧钢在0.5-7.0 mol/L H2SO4溶液中的缓蚀作用。结果表明：吐温-60对冷轧钢在1.0 mol/L H2SO4溶液中具有良好的缓蚀作用,且在钢表面的吸附符合校正的Langmuir吸附模型。缓蚀率随缓蚀剂浓度的增加而增大,但随温度和硫酸浓度的增加而减小。求出了相应的吸附热力学（吸附自由能ΔG^0, 吸附焓ΔH^0, 吸附熵ΔS^0）和动力学参数（腐蚀速率常数k, 腐蚀动力学常数B）,并根据这些参数讨论了缓蚀作用机理。     

2-Aminothiazole derivatives as Adsorption Inhibitors for corrosion of commercial copper and brass in acid solutions

Corrosion inhibition of commercial copper and cold-worked and annealed α-brass (Cu/Zn : 69/31) in acid chloride solutions by some 2-aminothiazole derivatives was studied by weight loss, polarization and capacitance measurements. The study includes the effect of substituent type at position 4, the inhibitor concentration and pH on the efficiency of inhibition. The results showed that the inhibition occured via chemisorption of the inhibitor molecules on the corroding metal following Temkin's isotherm and the adsorption process involved the electron donation from the inhibitor to the metal surface. Quantitatively the inhibition efficiency was found to run parallel to the electron density on the thiazole molecule according to Hammett's relation and the sensitivity of the process is independent of the corroding metal. The inhibition efficiency was found to decrease significantly as the solution pH deceases due to the protonation of the inhibiting molecules.     

The Inhibition Behaviour of some 1,2-azole derivatives for the corrosion of mild steel in sulphuric acid solutions

The corrosion inhibition of mild steel in sulphuric acid solutions by two series of 1,2-azole derivatives was studies by using weight loss, polarization and capacitance measurements. Series 1 derivatives were 3-methy1-5-amino-1,2-azoles (azole = pyrazole, isoxazole and isothiazole) and series 2 derivatives were 3(5)-amino-5(3)[4′-X-phenyl]pyrazoles (X = H-, Cl?, NO^2?, Me? and MeO?). The effect of inhibitor concentration, temperature, acidity and chloride ion concentration on the inhibition efficiency was also investigated. The inhibition was found to increase with increase of the inhibitor concentration and decrease of temperature, acidity and chloride ion concentration. Generally, the inhibition efficiency was found to increase with increase of the azole basisity and the electron density on the azole ring. The inhibition occurs through adsorption of the inhibitor molecules onto the metal surface following Temkin isotherm. The nature of the inhibitive species and the modes of adsorption were discussed.     

Synergistic inhibition between OP and NaCl on the corrosion of cold-rolled steel in phosphoric acid

The effects of single OP and the mixture of various concentrations of OP and 0.1 M NaCl on the corrosion of cold-rolled steel in 1.0–3.5 M phosphoric acid have been investigated by using weight loss method and polarization method. This study revealed that cold-rolled steel in phosphoric acid has been more efficiently inhibited by OP in the presence of NaCl than single OP, and inhibition efficiency increases with increasing concentration of OP at the same temperature, but decreases with increasing temperature studied. A synergistic effect exists when OP and chloride ion are used together to prevent cold-rolled steel corrosion in 1.0–3.5 M phosphoric acid at every experimental temperature. The polarization curves showed that OP is a cathodic inhibitor, while the complex of OP and NaCl is a mixed-type inhibitor that mainly inhibits the cathodic corrosion of the steel. The experimental results suggested that the presence of chloride ion in the solution stabilized the adsorption of OP molecules on the metal surface and improved the inhibition efficiency of OP. The adsorption of single OP follows the Langmuir adsorption isotherm, and the adsorption of the complex accords with the Langmuir adsorption isotherm too. Some thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy have been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have been calculated and discussed. In 1.5–3.5 M phosphoric acid, the concentration pre-exponential factor and acid concentration constant have been calculated, and the synergistic effect has been observed too.     

The synergistic inhibition between hexadecyl trimethyl ammonium bromide (HTAB) and NaBr for the corrosion of cold rolled steel in 0.5 M sulfuric acid

The synergistic effect of the mixture of hexadecyl trimethyl ammonium bromide (HTAB) and various concentrations of NaBr on the corrosion of cold rolled steel in 0.5 M sulfuric acid has been investigated using weight loss method and polarization method. The results reveal that the corrosion of cold rolled steel has been efficiently inhibited by HTAB in the presence of NaBr in sulfuric acid, and inhibition efficiency increases with increasing concentration of NaBr at the same temperature. A synergistic effect has been observed for HTAB with NaBr at every experimental temperature. The polarization curves show that the complex of HTAB and NaBr is a mixed-type inhibitor. The experimental results suggest that the presence of bromide ion in the solution stabilizes the adsorption of HTAB molecules on the metal surface and improves the inhibition efficiency of HTAB. Langmuir adsorption isotherm equation was obeyed at all the temperatures studied. The synergism parameters have been calculated and discussed. The results obtained from weight loss method and polarization method are in good agreement.