钨酸盐对镁合金在3.5%NaCl介质中的缓蚀作用

研究钨酸钠对AZ61镁合金在3.5%NaC l腐蚀介质中的缓蚀作用.电化学阻抗谱(EIS)、Tafel极化曲线、扫描电子显微镜(SEM)等测试表明,钨酸钠缓蚀剂可有效抑制镁合金在NaC l介质中的腐蚀,当钨酸钠浓度为0.01 mol.L-1可达到较好的缓蚀效果,缓蚀效率达75.5%.钨酸钠可参与镁合金表面膜的形成,使表面膜更致密,从而抑制镁合金的腐蚀;其缓蚀作用属于阳极抑制型缓蚀机理.     

5-苯基-1H-四氮唑对铜片缓蚀性能的研究

通过金相显微镜和接触角测试研究了5-苯基-1H-四氮唑在硫-乙醇体系中对铜的缓蚀性能。结果显示,缓蚀剂可以在铜片表面形成疏水性保护膜,有效抑制了铜片的腐蚀。电化学测试表明,当缓蚀剂浓度为70 mg/L时缓蚀效率达到87%,对铜电极有明显的缓蚀作用。通过量子化学密度泛函理论研究了缓蚀剂分子结构与缓蚀性能的关系,分析了缓蚀剂分子的活性位点。通过分子动力学模拟研究了缓蚀剂分子在Cu的(111)表面的吸附行为。     

SDBS与HA缓蚀剂复配的实验与理论研究

通过静态失重法研究了十二烷基苯磺酸钠(SDBS)与六亚甲基四胺(HA)在盐酸溶液中对Q235钢的协同缓蚀效应, 并采用分子动力学模拟从缓蚀剂膜抑制腐蚀粒子扩散的角度对其缓蚀机理进行分析. 结果显示: SDBS和HA单独使用时, 最高缓蚀效率分别为82.82%和79.46%, 复配后最高缓蚀效率可达到92.78%; 与两种缓蚀剂单独使用时相比, SDBS与HA复配后缓蚀剂膜体系中的自由空间明显下降, 削弱了膜内缓蚀剂分子的自扩散能力, 腐蚀粒子在缓蚀剂膜携带下的被动迁移也随之减弱; SDBS与HA复配能更有效抑制腐蚀粒子在缓蚀剂膜中的扩散, 也就是说复配后的缓蚀剂具有更好的缓蚀性能.     

噻二唑型缓蚀剂对银片的缓蚀性能

采用增重法和金相显微技术,研究了不同浓度的沉降硫-石油醚溶液对银片的腐蚀作用,以及噻二唑型缓蚀剂TSJ-T6在不同浓度、不同温度下的缓蚀效率。 研究表明,TSJ-T6缓蚀剂对银片具有很好的缓蚀性能,且随着缓蚀剂浓度的增加,缓蚀效率也随之提高,当缓蚀剂浓度达到10.0 μg/g时,缓蚀效率达到94.37%。 经过吸附等温线拟合,得到缓蚀剂TSJ-T6在银片表面的缓蚀符合Langmuir吸附等温式,吸附过程为放热反应过程。     

聚乙烯吡咯烷酮对模拟混凝土孔隙液中钢筋的缓蚀效应

应用电化学阻抗谱和极化曲线测试技术,结合扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和拉曼(Raman)光谱分析,研究了表面活性剂聚乙烯吡咯烷酮(PVP)作为缓蚀剂对钢筋的缓蚀效应和机理.结果表明,PVP对pH值为11.0,含0.5 mol/L NaCl的模拟混凝土孔隙液中的钢筋具有良好的缓蚀作用,可有效抑制钢筋的腐蚀;PVP浓度变化对钢筋腐蚀行为有显著的影响,当浓度为25 mg/L时,PVP对钢筋的缓蚀效率达到89.1%;PVP通过在钢筋表面形成吸附膜来抑制钢筋的腐蚀.     

Gemini型咪唑啉双季铵盐金属缓蚀剂的合成及其性能

合成了系列新型咪唑啉双季铵盐阳离子缓蚀剂(S-HSJ),研究并讨论了其在5%HCl介质中对铜、铁、铝等金属的缓蚀性能及缓蚀剂结构中亲油基部分碳链长度、缓蚀时间、缓蚀剂浓度等对缓蚀效果的影响. 研究表明,S-HSJ系列咪唑啉双季铵盐对红铜、黄铜、铝及马口铁四种金属均表现出较传统单季铵盐与苯并三氮唑缓蚀剂好的缓蚀性能,S-HSJ-16双季铵盐添加量0.1%时缓蚀效率可达94%~99%,S-HSJ与阴离子表面活性剂复配对铜腐蚀表现出明显协同效应.     

阳离子型可聚合咪唑类离子液体-丙烯酰胺共聚物的制备及其对盐酸腐蚀碳钢缓蚀行为

利用阳离子型可聚合离子液体1-丙烯酰氧乙基-3-甲基咪唑四氟硼酸盐与丙烯酰胺的反相微乳液共聚合,制备了阳离子型咪唑类离子液体-丙烯酰胺共聚物缓蚀剂,并探讨了其缓蚀性能。研究了不同阳离子度、不同浓度聚合物溶液的缓蚀性能以及吸附时间对盐酸腐蚀碳钢速率的影响,并初步讨论了缓蚀机理。研究表明,该种阳离子型缓蚀剂的缓蚀效率可达90%以上;缓蚀剂的缓蚀能力不仅取决于缓蚀剂的阳离子度,还取决于该种缓蚀剂的相对分子质量;缓蚀效率并非简单地随聚合物浓度的增加而提高,当聚合物溶液的浓度过高时,反而会使缓蚀效率下降;随吸附时间的延长,碳钢的腐蚀速率逐渐降低,约40 h后基本保持不变;加入缓蚀剂有效抑制了酸对铁的腐蚀,随缓蚀效率的提高,碳钢表面的粗糙程度明显降低,孔洞结构减少。     

绿色聚天冬氨酸复配缓蚀剂对A3碳钢的缓蚀抑雾作用

采用失重法和极化曲线法研究了聚天冬氨酸(PASP)和十二烷基酚聚氧乙烯醚(OP-10)复配对A3碳钢在6mol·L-1HCl腐蚀介质中的协同吸附行为及缓蚀抑雾作用.结果表明:复配缓蚀剂可有效抑制A3碳钢在HC1介质中的腐蚀,当PASP浓度为20g·L-1,缓蚀率可达94%,抑雾率83%;随着温度的升高,复配缓蚀剂的缓蚀性能下降.复合缓蚀剂在钢表面的吸附符合校正的Langmuir模型,吸附过程为放热、熵减的自发过程;复配体系属于阳极型缓蚀剂.     

噻二唑衍生物对银的缓蚀性能研究

本文研究了主要成分为5-甲基-2-戊基二硫代-1,3,4-噻二唑的复配型缓蚀剂TSJ-T6,在浓度为5.0×10-5g/g的H2S中对银的缓蚀性能。通过增重实验、接触角分析、电化学极化曲线测试以及分子动力学模拟研究了该缓蚀剂的缓蚀效率及缓蚀机理。增重实验结果证明,缓蚀剂TSJ-T6对银片在H2S中的腐蚀具有良好的缓蚀效果,缓蚀剂浓度为2.5×10-5g/g时,缓蚀效率高达94.51%。接触角分析结果表明,该缓蚀剂分子在银片和腐蚀液的界面形成了一层疏水保护膜。极化曲线结果表明,缓蚀剂TSJ-T6的存在降低了阴、阳极的塔菲尔斜率,为混合型缓蚀剂;同时,该缓蚀剂的存在显著降低了腐蚀电流密度,表明该缓蚀剂对银片在H2S中的腐蚀有良好的缓蚀效果。分子动力学模拟表明,缓蚀剂分子通过噻二唑环和链上的硫、氮原子吸附在银表面,烷基链则以一定角度指向溶液。     

十二烷基苯磺酸钠在AZ31镁合金表面的吸附及其缓蚀作用

采用电化学阻抗谱(EIS)和极化曲线研究十二烷基苯磺酸钠(SDBS)对AZ31镁合金在3.5%(w, 质量分数)NaCl腐蚀介质中的吸附行为及缓蚀作用. 结果表明: SDBS可有效抑制AZ31镁合金在NaCl介质中的腐蚀, 其浓度为0.008 mol·L-1时缓蚀效率可达90%以上; 升高温度并不利于提高SDBS的缓蚀效率. SDBS在AZ31镁合金表面主要发生物理吸附, 吸附过程为放热、熵增的自发过程, 近似符合Langmuir单分子层吸附模型; SDBS为混合抑制型缓蚀剂, 但主要抑制阳极反应.     

硫酸溶液中聚天冬氨酸对碳钢的吸附缓蚀性能

应用电化学极化曲线和交流阻抗研究聚天冬氨酸(PASP)对碳钢的缓蚀性能,讨论了PASP浓度和温度对缓蚀效果的影响.结果表明:PASP是一种以抑制阳极为主的缓蚀剂.在实验温度范围内,PASP在0.5mol/L硫酸溶液中对碳钢的缓蚀效率随着温度升高而降低,并以10℃时的缓蚀效果最好.在给定温度下,缓蚀率均随PASP浓度的增加而迅速增加,但当PASP质量浓度达到2.5g/L时,缓蚀率的增加趋于平缓,10℃下,缓蚀率的最高值可达80.33%(PASP 6.0g/L),PASP在碳钢表面的吸附基本服从Freund lich吸附等温式,PASP的加入增大了碳钢的腐蚀反应表观活化能.     

2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在柠檬酸溶液中对碳钢的缓蚀作用

采用失重实验、极化曲线和交流阻抗等方法研究了缓蚀剂2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在质量分数为2%柠檬酸溶液中对碳钢的缓蚀性能。 失重实验表明,该缓蚀剂在柠檬酸溶液中能够有效地抑制碳钢的腐蚀,当其质量分数为0.4%时,缓蚀效率达到86.4%。 极化曲线表明,该缓蚀剂为混合型缓蚀剂,Nyquist图中单一的容抗弧变化表明碳钢电极表面的腐蚀过程主要由电荷转移步骤控制。 该缓蚀剂的吸附行为符合Langmuir吸附等温式,吸附机理是介于物理吸附和化学吸附之间的一种吸附。     

氯化硝基四氮唑蓝对钢在盐酸溶液中的缓蚀作用

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了氯化硝基四氮唑蓝(NTBC)在1.0-5.0mo·lL-1HCl溶液中对冷轧钢(CRS)的缓蚀作用.结果表明:NTBC在1.0mo·lL-1HCl溶液中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.缓蚀率随缓蚀剂浓度的增加而增大,但随盐酸浓度和温度的增加而减小.求出了相应的吸附热力学(吸附自由能ΔG0,吸附焓ΔH0,吸附熵ΔS0)和腐蚀动力学参数(腐蚀速率常数k,动力学常数B),并根据这些参数讨论了缓蚀作用机理.动电位极化曲线表明:NTBC为混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区出现感抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.SEM再次表明NTBC对钢在盐酸介质中的腐蚀产生了明显的抑制作用.     

Adsorption,Thermodynamic, and Experimental Studies of Corrosion Inhibitor of Tin in 0.2 M Maleic Acid by Hydrogen Phosphate Ions (HPO42−)

The inhibition efficiency of H₂PO₄²⁻ ions against tin corrosion in 0.2 M maleic acid is studied using electrochemical methods, surface analytical methods, and thermodynamic analysis. The potentiodynamic polarization plots showed the presence of an active/passive transition state of the tin electrode. The EIS measurements confirmed that the inhibition efficiency of H₂PO₄²⁻ increased by increasing the concentration (η=81 % at C_inh=2.10⁻² M) and decreased by rising the temperature. The polarization tests demonstrated that the inhibitor performs as a cathodic-type. The adsorption of the inhibitor was spontaneous and followed the Langmuir adsorption isotherm. A model of the inhibition mechanism was suggested.     

柠檬酸中锌防蚀剂（1,3-Dioxolan-2-ylmethyl）三苯基溴化磷和碘离子的协同效应研究

采用称重法、动电位极化法和电化学交流阻抗技术研究了30 ^oC时(1,3-Dioxolan-2-ylmethyl)三苯基溴化磷（DTPB）对0.5 mol·L^-1柠檬酸中锌腐蚀行为的影响. 通过在环保型电解槽中对锌进行酸洗,这在文献中是不常用的. 结果表明,DTPB作为一种有效的防蚀剂,添加浓度仅为3×10^-3 mol·L^-1时,锌在柠檬酸溶液中的防蚀效率可达98.9%. 由于DTPB和碘化钾存在协同效应,两者联用时的防蚀效果要比单独使用DTPB强,防蚀参数为1.2,并随温度升高而减小. 本文提出了碘化钾作为吸附媒介,可使金属表面与DTPB结合的防蚀机制.     

Influence of Molecular Weight on Mild Steel Corrosion Inhibition Effect by Polyvinyl Alcohol in Hydrochloric Acid Solution

The corrosion inhibition of mild steel in hydrochloric acid solution in the presence of three different molecular weights of polyvinyl alcohol (PVA) designated as PVA-I, PVA-II, and PVA-III corresponding to 14,000, 72,000, and 125,000 g mol^?1, respectively, was investigated using electrochemical impedance spectroscopy, linear polarization resistance (LPR), and potentiodynamic polarization techniques at 25°C. It was found that PVA of different molecular weights inhibited the corrosion of mild steel in the acid environment. Inhibition efficiency (η%) increases with increase in concentration of the polymers. LPR measurements clearly show that inhibition efficiency increases with increasing molecular weight in the order PVA-III > PVA-II > PVA-I. Polarization curves indicate that PVA functions as a mixed inhibitor affecting both the anodic metal dissolution and cathodic hydrogen evolution partial reactions of the corrosion process. The experimental data obtained fitted well into Langmuir adsorption isotherm model. Physical adsorption mechanism is proposed from the thermodynamic (free energy of adsorption) parameters obtained.     

Adsorption and inhibition performance of the novel cationic Gemini surfactant as a safe corrosion inhibitor for carbon steel in hydrochloric acid

The new synthesized cationic Gemini surfactant (CGS) was tested as a corrosion inhibitor for carbon steel (CS) in 1.0?M hydrochloric acid using weight loss, electrochemical spectroscopy and potentiodynamic polarization. The inhibition efficiency is increased by increasing the CGS concentration and is almost constant within the temperature range studied. The inhibition was explained by adsorption of the CGS molecule on the CS surface. A mixed-type inhibitor is suggested for the inhibitory effects of CGS as revealed by the potentiodynamic polarization technique. The changes in impedance parameters suggested that the adsorption of the inhibitor on the CGS surface led to the formation of protective films. The adsorption of the CGS on the surface of CS obeys Langmuir adsorption isotherm. Thermodynamic and kinetic parameters were calculated and discussed.     

Cupressus arizonica fruit essential oil: A novel green inhibitor for acid corrosion of carbon steel

Natural-based corrosion inhibitors have gained great research interest thanks to their low cost and higher performance. The Cupressus arizonica fruit essential oil (CAFEO) has a higher extraction yield than leaves; however, it has less antibacterial and antifungal activities. The three main components in the CAFEO were α-pinene (51.07%), myrcene (17.92%), and limonene (9.66%). Essential oils with a higher percentage of α-pinene were found to have outstanding corrosion inhibition properties. Therefore, herein, the CAFEO was investigated as a green corrosion inhibitor for carbon steel (CS) in 1.0 mol/L HCl using electrochemical, i.e., potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) techniques. The experimental results revealed that CAFEO successfully inhibited the carbon steel corrosion in 1.0 mol/L HCl solution. Results from PDP indicated that the inhibitor had a mixed-type effect with a predominance cathodic character. EIS data showed that the charge transfer resistance of the CS electrode increased from 20.9 Ω cm² in blank solution to 294.5 Ω cm² in HCl solution inhibited with 0.5 g/L of CAFEO at 298 K, leading to a significant decrease in the double layer capacitance values and an inhibition efficiency (η%) of 93%. The high temperatures showed a negative effect on the corrosion inhibition efficiency of the tested inhibitor. At 323 K, the η% of CAFEO decreased to 77%. Besides, SEM images showed that the inhibitor formed a protective barrier against acid attack, preventing carbon steel from corrosion. Theoretical calculations by Density Functional Theory (DFT) were performed to investigate the reactivity of the three main components of CAFEO.     

Study on the inhibition of mild steel corrosion by 1,3-bis-(morpholin-4-yl-phenyl-methyl)-thiourea in hydrochloric acid medium

1,3-Bis-(morpholin-4-yl-phenyl-methyl)-thiourea (MBT) was synthesized and their influence on the inhibition of corrosion on mild steel in various hydrochloric acid concentrations has been investigated by weight loss, potentiodynamic polarization, electrochemical impedance (EI), Tafel polarization, scanning electron microscope (SEM) and FT-IR methods. The result of weight loss study shows that the corrosion inhibition efficiency (IE) is directly proportional to the concentration of the inhibitor and inversely proportional to the temperature. Electrochemical study proved that the inhibitor acts as a mixed type inhibitor. SEM shows the formation of a protective film of the inhibitor on the mild steel. The IR data also provide evidence for the anticorrosion effect of the inhibitor.     

滑竹叶提取物在HCl介质中对铝的缓蚀性能

采用失重法、动电位极化曲线、电化学阻抗谱、红外光谱、紫外光谱和扫描电子显微镜研究了滑竹叶提取物(YPLE)在1.0 mol/L HCl介质中对铝的缓蚀作用。结果表明,YPLE对铝具有良好的缓蚀作用,缓蚀率随其浓度的增加而增大,且在铝表面的吸附符合Langmuir吸附等温式。YPLE为阴极抑制型缓蚀剂;电化学阻抗谱在高频区呈容抗弧,在低频区呈感抗弧,添加YPLE后,阻抗值显著增大。SEM表明,添加YPLE对铝的腐蚀产生了明显的抑制作用。