木薯淀粉-丙烯酰胺接枝共聚物在NaCl溶液中对钢的缓蚀性能

以过硫酸铵-亚硫酸氢钠[(NH_4)_2S_2O_8-NaHSO_3]作为引发剂,用烯类单体丙烯酰胺(AA)对木薯淀粉(CS)进行化学接枝共聚改性合成制备了木薯淀粉-丙烯酰胺枝共聚物(CS-AAGC)。用动电位极化曲线和电化学阻抗谱(EIS)研究了CS-AAGC在20℃时0.5mol/LNaCl溶液中对冷轧钢的缓蚀性能。结果表明,CS-AAGC对冷轧钢具有良好的缓蚀性能,当缓蚀剂浓度为100mg/L时缓蚀率超过85%;CS-AAGC为阳极型缓蚀剂;Nyquist图谱为单一容抗弧,添加CS-AAGC后电荷转移电阻显著增大。CS-AAGC可通过物理和化学吸附在钢表面产生吸附作用,且吸附行为服从Langmuir吸附方程式。     

木薯淀粉-丙烯酰胺接枝共聚物对冷轧钢在NH_4Cl溶液中的缓蚀作用

对木薯淀粉高分子聚合物进行接枝共聚改性得到木薯淀粉-丙烯酰胺接枝共聚物(CS-AAGC),采用失重法、电化学法和扫描电子显微镜(SEM)形貌分析研究了CS-AAGC作为缓蚀剂对冷轧钢在0.5 mol/L NH_4Cl溶液中的腐蚀抑制效果,并对缓蚀性能影响规律和缓蚀作用机理进行探究。结果表明,CS-AAGC作为缓蚀剂对冷轧钢在0.5 mol/L NH_4Cl溶液中的腐蚀抑制效果明显,随着CS-AAGC的浓度增大,η_w增大,当浓度为500 mg/L时,缓蚀率达到了90.2%,由极化曲线也得出了同样的结论;CS-AAGC在冷轧钢表面的吸附服从Langmuir吸附等温式,通过静电作用和共价键等物理和化学方式在冷轧钢表面形成吸附膜层;极化曲线表明CS-AAGC为混合抑制型缓蚀剂,能够有效控制阴极析氢腐蚀和阳极溶解过程;阻抗谱为单一压缩容抗弧,添加CS-AAGC后,电荷转移电阻增大,腐蚀反应速率降低,SEM微观形貌进一步证实了CS-AAGC能够显著减缓冷轧钢在0.5 mol/L NH_4Cl介质中的腐蚀。     

核桃青皮缓蚀剂的提取制备及其缓蚀性能

以乙醇水溶液为提取溶剂,采用回流提取法从核桃青皮中提取制备了核桃青皮缓蚀剂(WGHI),并用失重法、动电位极化曲线、EIS、UV、FTIR和SEM测试了WGHI对冷轧钢在0.5 mol/L HCl溶液中的缓蚀性能。结果表明:乙醇体积分数为40%时,提取制备出的WGHI产率和缓蚀率均较佳,分别为14.2%和90.3%。WGHI对冷轧钢在0.5 mol/L HCl溶液中的腐蚀具有明显抑制作用,且随着WGHI质量浓度的增加缓蚀性能逐渐增强,但随温度的升高有所下降,20℃时100 mg/L WGHI的缓蚀率为90.3%。WGHI通过物理和化学吸附方式在钢表面发生吸附,吸附过程中会释放出热量,同时混乱度减小,该吸附规律遵循Langmuir吸附方程。添加WGHI后同时抑制了钢的阴极和阳极腐蚀反应,为混合抑制型缓蚀剂;Nyquist呈单一弥散容抗弧,其阻抗值随WGHI质量浓度的增加而显著增大。SEM结果显示:WGHI能有效减缓钢表面在HCl溶液中的腐蚀并且降低了其表面粗糙度。     

银杏叶提取物对冷轧钢在H_3PO_4溶液中的缓蚀性能

用失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了银杏(Ginkgo)叶提取物(GLE)对冷轧钢在1.0 mol/L H3PO4溶液中的缓蚀性能。结果表明:GLE对冷轧钢在H3PO4溶液中具有良好的缓蚀作用,缓蚀率随缓蚀剂浓度的增加而增大,且随温度的升高而增大,GLE在钢表面的吸附符合Langmuir吸附等温式。动电位极化曲线表明,GLE为混合抑制型缓蚀剂。EIS高频区呈容抗弧,低频区有小段感抗弧,添加GLE后阻抗值显著增加,表现出良好的缓蚀性能。     

元宝枫叶提取物在盐酸溶液中对钢的缓蚀性能研究

天然植物元宝枫(acer truncatum)叶的提取物可作为一种环境友好型缓蚀剂.采用失重法、动电位极化曲线和交流阻抗(EIS)研究了元宝枫叶提取物在1.0mol/L HCl溶液中对冷轧钢的缓蚀作用.结果表明:元宝枫叶提取物对冷轧钢具有良好的缓蚀作用,且在钢表面的吸附符合Langmuir吸附等温式.极化曲线表明,元宝枫提取物为阴极抑制型缓蚀剂;EIS谱呈半圆容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.     

木薯淀粉接枝共聚物对冷轧钢在CH_3COOH溶液中的缓蚀作用

用失重法和动电位极化曲线研究了木薯淀粉接枝共聚物(CSGC)在0.3 mol/L CH_3COOH溶液中对冷轧钢的缓蚀作用。结果表明:CSGC对冷轧钢具有良好的缓蚀作用,当缓蚀剂用量为200 mg/L时,最大缓蚀率可超过80%。CSGC在钢表面的吸附符合Langmuir吸附等温式;求出了吸附热力学参数(吸附平衡常数K,标准吸附Gibbs自由能ΔG°)和动力学参数(表观活化能Ea、指前因子A、活化焓ΔH≠、活化熵ΔS≠),并据此探讨了CSGC在钢表面的吸附行为。极化曲线表明CSGC为混合抑制型缓蚀剂。     

三氯乙酸介质中木质素磺酸钙对冷轧钢的缓蚀性能

通过失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了三氯乙酸(Cl_3CCOOH)溶液中阴离子表面活性剂木质素磺酸钙(CLS)在冷轧钢表面上的吸附行为及其缓蚀性能,采用扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试探究了钢表面的微观形貌结构及亲水/疏水性。结果表明,CLS有效抑制了冷轧钢在0.10 mol/L Cl_3CCOOH溶液中的腐蚀,25℃和30℃时2.0 g/L CLS的最大缓蚀率值高于90%,缓蚀性能随CLS添加量的增加而增大,但与温度的关系呈负相关。CLS在钢表面的吸附规律满足Langmuir吸附等温式,吸附方式是放热的物理吸附为主的混合吸附。添加CLS后有效抑制了钢在三氯乙酸中的阴极腐蚀反应,且电荷转移电阻显著上升。钢在添加CLS后,腐蚀程度和表面粗糙度急剧降低,表面疏水性增强。     

溴化十六烷基吡啶在硫酸溶液中对钢的缓蚀性能研究

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)、扫描电子显微镜(SEM)及原子力显微镜(AFM)研究了阳离子表面活性剂溴化十六烷基吡啶(HDPB)在1.0 mol/L H2SO4溶液中对冷轧钢的缓蚀性能.结果表明:HDPB具有良好的缓蚀性能,缓蚀率随缓蚀剂浓度和温度的增加而增大,50℃时100 mg/L HDPB的最大缓蚀率可高达98.2％.HDPB属于混合抑制型缓蚀剂,添加HDPB后电荷转移电阻显著增大,且SEM与AFM的微观形貌进一步证实了HDPB有效减缓了冷轧钢表面的腐蚀程度.     

中性红在盐酸溶液中对冷轧钢的缓蚀作用

用失重法和动电位极化曲线法研究了酸碱指示剂中性红对冷轧钢在1.0～8.0 mol/LHCl溶液中的缓蚀作用.结果表明:中性红对冷轧钢在1.0 moL/L HCl溶液中具有良好的缓蚀作用,为混合抑制型缓蚀剂,且在钢表面的吸附符合校正的Langmuir吸附等温式,缓蚀率随缓蚀剂浓度的增加而增大,但随温度和盐酸浓度的增加而减小.通过吸附理论求出了相应的吸附热力学(吸附自由能△G°,吸附热△H°,吸附熵△S°)和动力学参数(腐蚀速度常数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.     

HCl中稀土盐硫酸高铈对1060铝板的缓蚀性能研究

采用静态失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了稀土盐硫酸高铈[Ce(SO_4)_2·4H_2O]对1.0 mol/L HCl中1060铝板的缓蚀性能,并通过扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试深度表征铝表面的微观形貌特征和亲水/疏水性。结果表明,硫酸高铈能有效抑制1060铝板在1.0 mol/L HCl中的腐蚀,表现出良好的缓蚀性能,20℃时100 mg/L Ce(SO_4)_2·4H_2O的缓蚀率高达94.3%。硫酸高铈在铝表面的吸附符合Langmuir吸附等温式,标准吸附Gibbs自由能为-27.5 kJ/mol,吸附过程为物理和化学作用的混合吸附。极化曲线表明,硫酸高铈为阴极抑制型缓蚀剂;EIS有两个时间常数,Nyquist呈容抗弧(高频区)和感抗弧(低频区)组成的近似椭圆形特征。添加硫酸高铈后腐蚀电流密度急剧下降,但极化电阻显著增加。SEM和AFM均表明加入硫酸高铈后的铝表面的腐蚀明显减弱,表面粗糙度降低;但接触角和空白盐酸溶液相比增加约40°。     

Inhibition by <Emphasis Type="Italic">Jasminum nudiflorum</Emphasis> Lindl. leaves extract of the corrosion of cold rolled steel in hydrochloric acid solution

The inhibition effect of Jasminum nudiflorum Lindl. leaves extract (JNLLE) on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) was investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. The results show that JNLLE acts as a very good inhibitor, and the inhibition efficiency increases with the concentration of JNLLE. The adsorption of JNLLE obeys Langmuir adsorption isotherm. Values of inhibition efficiency obtained from weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) are in good agreement. Polarization curves show that JNLLE behaves as a mixed-type inhibitor in hydrochloric acid. EIS shows that charge-transfer resistance increase and the capacitance of double layer decreases with the inhibitor concentration, confirming the adsorption process mechanism. The adsorbed film on CRS surface containing JNLLE inhibitor was also measured by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). A probable inhibitive mechanism is proposed from the viewpoint of adsorption theory.     

An efficient corrosion inhibitor of cassava starch graft copolymer for aluminum in phosphoric acid

Starch is one of the richest natural polymers with low-cost,non-toxic and biodegradable,but is seldom directly used as corrosion inhibitor due to its poor inhibitive ability and low water solubility.To solve this problem,cassava starch-acryl amide graft copolymer (CS-AAGC) was prepared through grafting acryl amide (AA) with cassava starch (CS),and it was firstly examined as an efficient inhibitor for 1060 alu-minum in 1.0 mol·L-1 H3PO4 media.The adsorption behavior of CS-AAGC and its electrochemical mech-anism were investigated by weight loss and electrochemical methods.Additionally,the inhibited aluminum surface was fully characterized by a series of SEM,AFM,contact angle measurements and XPS.Results confirm that CS-AAGC performs better inhibitive ability than CS,AA or CS/AA mixture,and the maximum inhibition efficiency of 1.0g·L-1 CS-AAGC is 90.6％ at 20 ℃.CS-AAGC acts as a mixed-type inhibitor while mainly retards the anodic reaction.EIS has three time constants,and the polarization resistance is significantly increased in the presence of CS-AAGC.The micrograph of inhibited aluminum surface is of hydrophobic nature with low surface roughness and little corrosion degree.     

Starch-AA-CS三元共聚物对酸溶液中碳钢的缓蚀作用

以淀粉（Starch）、丙烯酸（AA）和壳聚糖（CS）为原料合成三元共聚物（SAAC）。利用红外光谱（FT-IR）和X射线衍射（XRD）进行结构表征,并通过电化学方法、失量法、扫描电子显微镜（SEM）和能谱仪（EDS）研究SAAC在1 mol·L^-1 HCl环境下对Q235碳钢的缓蚀作用及机理。结果显示,SAAC是一种混合型缓蚀剂,30℃时,200 mg·L^-1的SAAC的缓蚀率可达90.1%。通过Gibbs自由能和Tafel曲线可知,SAAC在Q235碳钢表面的吸附符合Langmuir吸附等温式,同时存在物理吸附与化学吸附。SAAC合成原料经济、环保,合成条件温和,是一种具有广泛应用前景的绿色环保型缓蚀剂。     

Effect of ethylenediamine tetraacetic acid disodium on the corrosion of cold rolled steel in the presence of benzotriazole in hydrochloric acid

The inhibition behavior of cold rolled steel in 0.1 M hydrochloric acid (HCl) by ethylenediamine tetraacetic acid disodium (EDTA) in the absence and presence of benzotriazole (BTA) was investigated with Tafel polarization curve and electrochemical impedance spectroscopy (EIS). The polarization curve results show that the single EDTA acts as an anodic type inhibitor while the combination of EDTA and BTA acts as mixed type inhibitor and mainly inhibits anodic reaction. All impedance spectra in EIS tests exhibit one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiencies obtained from Tafel polarization, charge transfer resistance (R_t) are consistent. The corrosion of cold rolled steel in 0.1 M HCl is obviously reduced by EDTA in combination with lower concentrations of BTA. Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) were used to characterize the corrosion surface of cold rolled steel. Probable mechanisms are present to explain the experimental results.     

Inhibition effect of methyl violet on the corrosion of cold rolled steel in 1.0 M sulfuric acid solution

The inhibition effect of methyl violet (MV) on the corrosion of cold rolled steel (CRS) in 1.0 M sulfuric acid (H₂SO₄) was investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. The results show that MV is a good inhibitor, and inhibition efficiency increases with inhibitor concentration, while decreases with the temperature. The adsorption of MV on CRS surface obeys Langmuir adsorption isotherm equation. The thermodynamic parameters of adsorption enthalpy (ΔH°), adsorption free energy (ΔG°) and adsorption entropy (ΔS°) are calculated and discussed. Potentiodynamic polarization curves show that MV acts as a mixed-type inhibitor in sulfuric acid. EIS exhibits one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiency values obtained from weight loss, polarization and EIS are in reasonably good agreement. The adsorbed film on CRS surface containing optimum dose of MV was investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Depending on the results, the inhibitive mechanism is proposed from the viewpoint of adsorption theory.     

In depth analysis of anti corrosion behaviour of eco friendly gum exudate for mild steel in sulphuric acid medium

The current research work was keen to examine the corrosion inhibition efficiency of mild steel (MS) in presence of aqueous extract of Araucaria heterophylla Gum (AHG) in 1?M H₂SO₄ medium. The phytoconstituents of the AHG were interpreted by GC-MS and corrosion inhibition efficiency was deduced using other techniques like weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Adsorption of inhibitor molecules on the mild steel surface was supported by Density Functional Theory (DFT) studies, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). It is seen from the results that the inhibitor exhibits optimum efficiency of 78.57% at 0.05% v/v on mild steel specimen in 1?M H₂SO₄ medium at room temperature. Tafel polarizations clearly show that the aqueous extract of AHG acts as a mixed type inhibitor. The change in the EIS parameters in presence of inhibitor is investigative of the protective layer formation of the mild steel surface. The adsorption is found to obey Langmuir adsorption isotherm. Thermodynamic and activation parameters for the corrosion inhibition process supported the physical adsorption mechanism.     

CHAMOMILE (Matricaria recutita) EXTRACT AS A CORROSION INHIBITOR FOR MILD STEEL IN HYDROCHLORIC ACID SOLUTION

The corrosion inhibition of mild steel in hydrochloric acid solution by chamomile (Matricaria recutita) extract (CE) was investigated through electrochemical (polarization, EIS) and surface analysis (optical microscopy/AFM/SEM) techniques. The effects of inhibitor concentration, temperature, and pH were evaluated. Thermodynamic parameters were calculated and adsorption studies were carried out. Finally, the surface morphology was investigated. The electrochemical studies showed that CE acts as a mixed-type corrosion inhibitor with predominantly anodic behavior. CE was adsorbed physically on the metal surface and obeyed the Langmuir adsorption isotherm. It impeded the corrosion processes by changing the activation energy. In the presence of CE, the metal surface was more uniform than the surface in the absence of inhibitor. Maximum inhibition efficiency (IE) was 93.28%, which was obtained at 22°C in 7.2 g/L of inhibitor in 1 M HCl solution.     

1-(2-Hydroxyethyl)-2-imidazolidinone as corrosion inhibitor of mild steel in 0.5 M HCl solution: thermodynamic,electrochemical and theoretical studies

The inhibition effect of 1-(2-Hydroxyethyl)-2-imidazolidinone (2-HEI) on mild steel (MS) corrosion in 0.5?M HCl solution was investigated at different inhibitor concentration and temperature by electrochemical experiments, such as linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and quantum chemical calculations. The inhibitor adsorption process on mild steel in 0.5?M HCl system was studied at different temperatures (20?°C–50?°C). Furthermore, the surface morphology of MS was also investigated with SEM in the absence and the presence of inhibitor. The adsorption of 1-(2-Hydroxyethyl)-2-imidazolidinone on MS surface is an exothermic process and this process obeys the Langmuir adsorption isotherm. The Quantum chemical findings are good agreed with the empirical data.     

Red tetrazolium as an effective inhibitor for the corrosion of cold rolled steel in 7.0 mol·L− 1 H2SO4 solution

The corrosion inhibition of cold rolled steel (CRS) in 7.0 mol·L^-1 H₂SO₄ solution by red tetrazolium (RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^-1 H₂SO₄, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^-1. The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics (MD) indicate that the adsorption center of RTZ⁺ (organic cationic part of RTZ) mainly relies on its tetrazole ring, and the adsorption of RTZ⁺ on Fe (001) surface is in a nearly flat orientation mode.