IAA 在硫酸溶液中对碳钢的缓蚀性能研究

目的研究吲哚-3-乙酸(IAA)在H2SO4(0.1 mol/L)溶液中对碳钢(Q235)的缓蚀性能,降低碳钢生产过程对环境的影响。方法采用动电位极化曲线测试、交流阻抗实验、失重实验和扫描电镜实验分析缓蚀剂的缓蚀性能及作用机理。结果 IAA的缓蚀效率随着缓蚀剂浓度的增加而逐渐增大,当IAA浓度增加到4×10-3mol/L时,缓蚀效率最高达到88.85%。温度升高,缓蚀效率降低,说明IAA不宜于高温下使用。IAA是一种混合型缓蚀剂,对阴极反应和阳极反应均有抑制作用,且在缓蚀剂分子吸附过程中,吸附在碳钢表面的水分子和缓蚀剂分子发生竞争吸附作用,能有效阻止H+的穿越,从而抑制腐蚀H+的放电。IAA在碳钢表面的吸附遵循Langmuir吸附等温模型,该吸附自发进行且是物理吸附和化学吸附共同作用。缓蚀剂通过抑制腐蚀反应的活性点,提高活化能垒,防止碳钢溶解腐蚀。IAA在碳钢表面形成保护膜,减轻了腐蚀。结论 IAA是一种以抑制阳极反应为主的混合型缓蚀剂,在0.1 mol/L H2SO4溶液中能够对Q235碳钢起到优异的保护作用。     

生物基缓蚀剂糠醇缩水甘油醚的缓蚀性能及机理

在生物基呋喃类缓蚀剂的研究基础上,利用Tafel极化曲线和电化学阻抗技术(EIS)研究了Q235碳钢在不同浓度的糠醇缩水甘油醚(FGE)盐酸溶液中的腐蚀行为,并通过静态失重实验分析了Q235碳钢在不同体系中的腐蚀速率。结果表明,4.92×10~(-4)mol·L~(-1)的FGE对Q235碳钢具有最好的缓蚀效果,其缓蚀效率达到94.0%,腐蚀速率为0.076 mg·cm~(-2)·h~(-1)。此外,经证明FGE在Q235碳钢表面的吸附过程符合Langmuir吸附模型,同时发生物理吸附和化学吸附。     

胡萝卜茎叶提取物对碳钢在0.5 mol/L H2SO4溶液中的缓蚀作用

目的研究胡萝卜茎叶提取物(DCSLE)在硫酸介质中对碳钢的腐蚀抑制作用及机理。方法通过超声辅助的手段,用水浸提获得DCSLE,利用红外光谱(FTIR)对其含有的主要官能团进行表征。在25~40℃下,采用失重法、电化学极化和阻抗法(EIS)评价DCSLE在0.5 mol/L H2SO4溶液中对碳钢的缓蚀性能,并讨论了其缓蚀机理。结果DCSLE对碳钢在0.5mol/LH2SO4溶液中的腐蚀具有良好的抑制效果,其缓蚀效率随浓度的增加而增加,随温度的增加而先增加后降低(40℃<25℃<30℃<35℃),35℃下,质量浓度为0.6g/L时,缓蚀效率为92.85%。电化学测试表明,DCSLE是混合型缓蚀剂,但主要是抑制阴极的反应。其缓蚀机理是:DCSLE以物理和化学混合吸附的方式吸附在碳钢表面,形成一层保护膜,从而阻止酸溶液的侵蚀,且吸附遵循Langmuir吸附等温模型。扫描电镜(SEM)观察到加入DCSLE后,碳钢的腐蚀得到了明显控制。结论DCSLE可以有效抑制碳钢在0.5mol/LH2SO4溶液介质中的腐蚀,是一种具有广泛应用前景的天然绿色缓蚀剂。     

向日葵盘提取物在0.5mol/L H2SO4溶液中对碳钢的缓蚀作用

以超声辅助法提取得到的向日葵盘提取物(HALE)为缓蚀剂,采用腐蚀浸泡试验、电化学试验研究HALE在0.5mol/L H2SO4溶液中对碳钢的缓蚀作用。结果表明:HALE对碳钢缓蚀效果良好,缓蚀率随HALE加量增加而增大,但随温度升高而降低;HALE在碳钢表面的吸附符合Langmuir吸附模型,是以物理吸附为主的混合吸附;电化学测试结果表明HALE是偏阳极混合抑制型缓蚀剂。     

硫酸介质中丙氨酸复合缓蚀剂的研究

目的研究丙氨酸和碘化钾共同存在于硫酸溶液中,对碳钢的协同缓蚀作用。方法采用极化曲线、交流阻抗谱、扫描电镜、X射线光电子能谱(XPS)以及El-Awady动力学模型,对丙氨酸、丙氨酸与碘化钾复配缓蚀剂对碳钢在硫酸介质中的缓蚀性能和吸附机理进行探究。结果在10%的硫酸体系中,对碳钢的缓蚀性能随着缓蚀剂浓度增大而增强。单独使用丙氨酸作为缓蚀剂,丙氨酸分子在碳钢表面呈单分子层吸附,缓蚀效率最高仅达到29%,缓蚀效果不明显。经过丙氨酸与碘化钾复配后,缓蚀效果显著提高,当丙氨酸质量浓度为300 mg/L,碘化钾质量浓度为250 mg/L时,缓蚀效率达到92%以上。XPS谱图表明,缓蚀剂主要是通过分子中的N原子与碳钢表面Fe原子形成共价键,吸附在碳钢的表面,与KI复配后,I-吸附在碳钢表面,并部分氧化,形成I_3~-。El-Awady动力学模型研究说明该复配缓蚀剂为混合型缓蚀剂,且在碳钢表面自发形成多分子层吸附膜。结论在10%的硫酸溶液中,丙氨酸分子通过物理吸附或化学吸附作用,吸附在碳钢表面,减缓腐蚀反应发生。碘化钾添加后,发挥连接缓蚀剂分子和碳钢表面的桥梁作用,从而协助丙氨酸吸附到碳钢表面,提高丙氨酸在碳钢表面的覆盖率,在提高缓蚀效率的同时,减少了丙氨酸的使用量,有效地抑制了钢材的腐蚀。     

含铬碳钢梯度材料扩散行为的研究

采用水溶液电沉积法在碳钢表面电镀铬并在高温下进行扩散退火处理,计算了铬在碳钢中的扩散系数,研究了铬在碳钢中的扩散行为。结果表明,铬在碳钢中的扩散系数范围为0.86×10~(-17)～8.34×10~(-17)m~2/s,扩散系数随退火温度升高而升高,碳钢中铬含量高的位置的扩散系统数降低。铬在碳钢中扩散激活能与铬含量无关,本实验条件下扩散激活能范围在73～89 kJ/mol之间。     

柚子皮提取物对热轧碳钢在HCl 溶液中的缓蚀作用研究

采用加热回流萃取法从柚子皮中提取天然缓蚀剂,并采用失重法和极化曲线法测试了提取物在30 ~50 ℃温度范围内,对热轧碳钢在2 mol/ L HCl 介质中的缓蚀性能。失重法测试结果表明,柚子皮提取物对热轧碳钢有良好的缓蚀作用,缓蚀效率随着温度的升高和缓蚀剂浓度的增加而增大,50 ℃时,最大缓蚀效率达到78. 4%。提取物在热轧碳钢表面的吸附作用符合Langmuir 吸附模型,以物理吸附为主。极化曲线测试结果表明,柚子皮提取物主要抑制热轧碳钢腐蚀反应的阴极过程,属于混合型缓蚀剂。     

H_2SO_4中香兰素在钢表面上的吸附及缓蚀作用

用失重法研究了在1.0 mol/L H2SO4中10～40℃香兰素(4-羟基-3-甲氧基-苯甲醛)在冷轧钢表面上的吸附及缓蚀作用.结果表明,香兰素对钢的缓蚀率随香兰素的浓度增加而增大,而随温度的增加而减小;香兰素在钢表面的吸附符合Temkin吸附模型.通过吸附理论和动力学Arrhenius公式分别求出了相应的吸附热力学参数(吸附自由能△G0,吸附热△HO,吸附熵△S0)和动力学参数(表观活化能Ea,指前因子A),并根据这些参数讨论了缓蚀作用机理.     

曼尼希碱酸化缓蚀剂的合成及缓蚀性能

目前,曼尼希碱的合成多在有机溶剂中进行,其中大多有机溶剂对人体有害。以苯乙酮、甲醛、二乙胺为原料,苄基三乙基氯化铵为相转移催化剂,以水为溶剂合成曼尼希碱酸化缓蚀剂。用失重法和电化学方法考察其浓度及腐蚀液温度对20碳钢缓蚀效果的影响。结果表明:该缓蚀剂为混合型缓蚀剂,在碳钢表面的吸附为物理吸附;随温度的升高缓蚀率逐渐减小,随浓度的增加缓蚀率先增大后减小;缓蚀剂的添加量为0.7%,温度35~55℃时缓蚀率都在90%以上,能有效抑制盐酸对碳钢的腐蚀。     

硫酸溶液中2-巯基苯并噻唑与氯离子的协同缓蚀作用

目的 提高缓蚀剂在酸溶液中的缓蚀性能.方法 构建含有2-巯基苯并噻唑(MBT)以及不同浓度Cl–的Fe表面溶液模型,并进行分子动力学计算.观察缓蚀剂分子在Fe表面的吸附构型,考察不同Cl–值下缓蚀剂膜的致密化行为.提取缓蚀剂分子的均方位移(MSD)曲线,评价缓蚀剂膜的稳定性.计算水分子的密度分布和扩散系数,考察不同Cl–值下MBT缓蚀剂膜的驱水能力和水分子的迁移能力.结果 当Cl–值从0增加到25时,MBT膜的厚度(0.42～1.51 nm)和致密度(占有面积0.33～1.31 nm2)增加,缓蚀剂分子的自扩散系数减小(从1.25×10–9 m2/s到接近0),水分子的吸附峰强度(相对密度为72.3～33.9 nm–3)和扩散系数(1.495×10–9～0.627×10–9 m2/s)降低.当Cl–值从25增加到36时,则出现了相反的趋势.结论 缓蚀剂分子与Cl–之间存在协同作用,适当浓度的KCl可以提高MBT缓蚀剂在H2SO4溶液中的缓蚀性能.Cl–值为25时,MBT缓蚀效率最高.     

Synergistic inhibition between tween 60 and NaCl on the corrosion of cold rolled steel in 0.5 M sulfuric acid

The corrosion inhibition of cold rolled steel in 0.5 M sulfuric acid in the presence of tween 60 and sodium chloride (NaCl) has been investigated by using weight loss and electrochemical techniques. The inhibition efficiency increases with increasing tween 60 concentration at the same temperature, but decreases with increasing temperature studied. A synergistic effect exists when tween 60 and chloride ions are used together to prevent cold rolled steel corrosion in 0.5 M sulfuric acid at every experimental temperature. The polarization curves show that tween 60 is a cathodic inhibitor, while the complex of tween 60 and NaCl is a mixed-type inhibitor. The experimental results suggest that the presence of chloride ions in the solution stabilizes the adsorption of tween 60 molecules on the metal surface and improves the inhibition efficiency of tween 60. The adsorption of single tween 60 follows the Temkin adsorption isotherm, but the complex accords with the Langmuir adsorption isotherm. Some thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy has been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have been calculated and discussed.     

Corrosion Inhibition of Mild Steel in Sulphuric Acid Using Luffa Aegyptiaca Leaves Extract

The corrosion inhibition of mild steel（MS） in sulphuric acid using Luffa aegyptiaca（LA） leaves extract was investigated by weight loss studies, colorimetric measurements, potentiodynamic polarisation and electrochemical impedance spectroscopy. The adsorption of LA leaves extract was confirmed by Fourier transform infrared spectroscopy and optical profilometry. The inhibition efficiency increased with increasing concentration of the extract but decreased with rise in temperature and with the increase in acid strength. Furthermore, the inhibition efficiency synergistically increased on the addition of halide ions. Polarisation studies revealed that the LA extract acts as mixed- type inhibitor. Physical adsorption mechanism is proposed from the trend in inhibition efficiency with the change in temperature and from thermodynamic parameters. The adsorption of LA on MS surface obeys Langmuir adsorption isotherm and follows the kinetic thermodynamic model of ElAwady at all temperatures studied.     

Synergistic inhibition between o-phenanthroline and chloride ion for steel corrosion in sulphuric acid

The corrosion inhibition of cold rolled steel in 0.5 M sulphuric acid in the presence of o-phenanthroline and sodium chloride (NaCl) has been investigated by using weight loss and electrochemical techniques. The experimental data suggest that the inhibition efficiency increases with increasing NaCl concentration in the presence of 0.0002 M o-phenanthroline, but decreases with increasing temperature. A synergistic effect is observed when o-phenanthroline and chloride ions are used together to prevent cold rolled steel corrosion in 0.5 M sulphuric acid. The polarization curves showed that the complex of o-phenanthroline and NaCl acts as a mixed type inhibitor. The experimental results suggested that the presence of chloride ions in the solution stabilized the adsorption of o-phenanthroline molecules on the metal surface and improved the inhibition efficiency of o-phenanthroline. The adsorption of the complex accords with the Langmuir adsorption isotherm. 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.     

Adsorption and Corrosion Inhibition Behavior of Polyethylene Glycol and Surfactants Additives on Mild Steel in H2SO4

The adsorption and corrosion inhibition behaviors of polyethylene glycol (PEG) alone and in the presence of surfactants sodium dodecyl benzene sulfonate and cetyltrimethyl ammonium bromide on mild steel in 0.1 M H₂SO₄ in temperature range of 30-60 °C was investigated using weight loss method, solvent analysis of iron ions, scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDAX), atomic force microscopy (AFM) and determination of kinetic/thermodynamic parameters. The inhibition efficiency (IE) of PEG increased with increasing concentration showing a maximum IE of 86.91% at 30 °C at 25 ppm but decreased with increasing temperature. Inhibiting action of PEG is synergistically enhanced on addition of small amount of surfactants. Surface morphology of the corroded mild steel specimen as evaluated by SEM, EDAX and AFM confirmed the existence of an adsorbed protective film on the mild steel surface. The calculated thermodynamic/kinetic parameters reveal that adsorption process is spontaneous and obey Langmuir adsorption isotherm.     

Formation of crystalline and amorphous solid solutions of W–Ni–Fe powder during mechanical alloying

The tungsten heavy alloy with the composition of 76.6W–17.3Ni–6.1Fe in atom percent was mechanically alloyed (MA) from the elemental powders of W, Ni and Fe. Nanocrystalline supersaturated solid solutions and amorphous phase were obtained during MA. Phase evolution, grain size and lattice distortion of these powders were determined and discussed. A thermodynamic model was developed based on semi-experimental theory of Miedema to calculate the driving force for phase evolution. The thermodynamic analysis showed that there is no chemical driving force to form the solid solution and the amorphous phase. The effect of the work of milling on the amorphization during MA was discussed and the model of multilayer amorphization during MA was applied to illustrate the feasibility of amorphization of powder with neither ΔH_mix0 nor D_BD_A. The driving force for amorphization is provided not by the negative heat of mixing or the stored energy in the grain boundaries but by the sharp concentration gradients in this system. Amorphization is mechanically driven and not by the negative heat of mixing. Crystallization is suppressed by sharp concentration gradients.     

红四氮唑对冷轧钢在磷酸溶液中的缓蚀性能

用失重法、动电位极化曲线和原子力显微镜（AFM）研究了红四氮唑对冷轧钢在1.0 mol/L~10.0 mol/L H₃PO₄溶液中的缓蚀作用。结果表明：红四氮唑对冷轧钢具有中等程度的缓蚀作用,为混合抑制型缓蚀剂,且在钢表面的吸附符合Freundlich吸附模型;通过吸附热力学和腐蚀动力学公式分别求出了相应的吸附热力学参数和动力学参数,并根据这些参数详细讨论了缓蚀作用机理;AFM测试结果表明添加红四氮唑后钢表面较为平整,粗糙度降低。     

Investigation of modified layered double hydroxide nanocontainer as a corrosion inhibitor for carbon steel in acidic medium

A modified layered double hydroxide (MLDH), was tested as a corrosion inhibitor for mild steel in 1 mol L^–1 HCl using electrochemical techniques. The inhibition efficiency was found to increase with increasing inhibitor concentration up to maximum 96.6% for 100 ppm at 30°C. The effects of temperature (35–65°C) on the inhibition of corrosion have also been investigated. The langmuir adsorption isotherm was found to provide the best explanation of the adsorption behavior of the investigated inhibitor on the mild steel surface. The calculated adsorption thermodynamic parameters reveal a physical adsorption of the inhibitors on the metal surface, endothermic process accompanied by an increase in entropy. Some samples of mild steel and MLDH particles were examined by SEM.     

NaOH溶液中表面活性剂对工业纯铝的缓蚀作用

采用失重法研究了阴离子表面活性剂油酸钠(SO)和阳离子表面活性剂溴化十四烷基吡啶(TDPB)在0.1mol/LNaOH溶液(20~50℃)中对工业纯铝的缓蚀作用。结果表明:SO在20~50℃时对铝基本无缓蚀作用。TDPB对铝在20℃和30℃时缓蚀效果较差;但在40℃和50℃时TDPB对铝具有良好的缓蚀作用,50℃时1.0×10-3mol/LTDPB对铝的最大缓蚀率为81.2%。TDPB在铝表面的吸附符合校正的Langmuir吸附模型,根据热力学公式求出了吸附热力参数(吸附自由能ΔG0,吸附焓ΔH0,吸附熵ΔS0),并用吸附观点讨论了缓蚀作用机理。     

The effect of temperature and concentration on the corrosion inhibition mechanism of an amphiphilic amido-amine in CO2 saturated solution

The corrosion inhibition mechanism of the N-[2-[(2-aminoethyl)amino]ethyl]-9-octadecenamide on mild steel surface in CO₂-saturated 5% NaCl solution has been studied. The inhibition efficiency decreases with increasing temperature. Adsorption of the inhibitor studied is found to follow the Frumkin adsorption isotherm. EIS results show that the mechanism of its corrosion inhibition at concentrations higher than critical micelle concentration is by forming a protective porous bi-layer. The activation energy, thermodynamic parameters and electrochemical results reveal a change in the adsorption mode of the inhibitor studied: the inhibitor could primarily be physically adsorbed at low concentrations, while chemisorption is favoured as concentration increases.     

Thermodynamic Evaluation of the Rehbinder Effect during Adsorption According to an S-Shaped Isotherm

A liquid solution–solid surface system with a single-component adsorption of surfactant is considered. The case in which the surfactant is represented by dodecyltrimethylammonium bromide (DTAB), while the solid surface is silica, is considered. Based on the previously developed thermodynamic theory of adsorption on the solid surface assuming its deformation, the dependence of the thermodynamic evaluation of the Rehbinder effect on the bulk concentration of surfactant in solution is investigated analytically. In calculations, a clear S-shaped experimental adsorption isotherm of DTAB on the nondeformed surface is employed. Using this isotherm, a piecewise approximating function is plotted, which yields the necessary concentration dependence and conditions of its dome shape in terms of the parameters of the theory. Experimental characteristics (rate of drilling) on granite, quartz, and microcline are compared with the theory represented by the dependence of the thermodynamic evaluation of the Rehbinder effect on the concentration of DTAB.