A novel process for copper protection in the simulated industrial cooling water based on click synthesis and self‐assembling method

The triazole inhibitor of 1‐(p‐tolylthio)‐1H‐1,2,3‐triazole‐4‐carboxylic acid (TTC) was synthesized via the Cu(I)‐catalyzed azide‐alkyne 1,3‐dipolar cycloaddition reaction. The self‐assembling method was performed to fabricate the self‐assembled film of TTC on the copper surface. The electrochemical measurement results indicate that the TTC film can efficiently protect the copper from corrosion in high concentrated industrial cooling water. The protection efficiency of TTC film for copper is 92.2%. Surface characterizations imply that the copper with TTC film after corrosion is covered with multiple protective layers. It probably contains Cu(I) and Cu(II) complexes mixed with nitrogenous compound, Cl^? and SO₄^2?. The result of quantum chemical calculation shows that the superior performance of TTC film is related to the adsorption of TTC molecules on copper surface horizontally. This kind of adsorption is mainly achieved via the adsorption centers of triazole ring and O atoms in TTC molecule.     

Corrosion resistance of 3,4‐dihydroxyphenylalanine/octadecylamine complex coatings on copper substrate

Octadecylamine (ODA) film assisted with the preferential adhesion of poly‐DOPA was prepared on copper substrates by dip‐coating method. The DOPA self‐polymerized and adhered membrane was firmed to the copper substrate in mild aqueous alkaline environments. By immersing the substrate coated with poly‐DOPA in its absolute ethyl alcohol solution, ODA was adsorbed onto the substrate to give a hydrophobic surface. The formation and surface structure of the film were characterized by water contact angle measurement (DA), and scanning electron microscopy. The corrosion behavior of the functional hybrid films was evaluated by electrochemical impedance spectroscopy. Experimental results show that the impedance of the composite films reaches to 10⁶ Ω, enhancing anti‐corrosion property of copper surface greatly.     

The nature of the copper sulfide film grown on copper in aqueous sulfide and chloride solutions

In this paper, the properties of copper sulfide films formed both anodically and naturally in deaerated/anoxic aqueous sulfide and chloride solutions were investigated using a series of electrochemical and surface analytical techniques. A combination of cyclic voltammetric, corrosion potential (E_corr), and cathodic stripping voltammetric experiments showed that the sulfide film growth kinetics and film morphologies were controlled by the supply of SH⁻ from the bulk solution to the copper surface. There was no passive barrier layer observed on the copper surface under either electrochemical or corrosion conditions. The film morphology was dependent on the type and concentration of anions (SH⁻, Cl⁻) present in the solution. Scanning electron microscopy on both surfaces and focused ion beam-cut cross-sections showed the growth of a thin, but porous, base layer of chalcocite (Cu₂S) after short immersion periods (up to 2 hr) and the continuous growth of a much thicker crystalline outer deposit over longer immersion periods (≥36 hr), suggesting a solution species transport-based film formation process and the formation of an ineffective thin “barrier-type” layer on copper.     

Effect of temperature on copper corrosion in high-level nuclear waste environment

The effect of temperature on the corrosion behavior of copper in simulated high-level nuclear waste environment was systematically studied. Electrochemical methods, including electrochemical impendence spectra, Mott–Schottky technology, cyclic polarization, and potentiostatic polarization, were employed to characterize the corrosion behavior of copper at different temperatures. Stereoscopic microscopy and scanning electron microscopy were used to examine the surface morphology, and X-ray photoelectron spectroscopy analysis was used to identify the composition of the passive film. The experimental results show that corrosion resistance of the passive film does not blindly decrease with the increase of temperature but increases at 60 °C owing to a compact outer layer; there is a potential for pitting corrosion, which decreases as the temperature increases. The main product of copper in an anaerobic aqueous sulfide solution is Cu₂S but the content of CuS increases at higher temperatures. The whole passivation range shows p-type semiconductor characteristics and the magnitude of the acceptor density is 10²³ cm^?3, which increases with increasing temperature.     

An investigation on the mechanisms of ant nest corrosion of copper tube in formic acid environment

Copper tubes used in air-conditioners and refrigerators often fail due to ant nest corrosion (ANC) in formic acid environment. In this paper, corrosion behavior and corrosion mechanisms of copper tubes in formic acid (HCOOH) were analyzed by vapor corrosion tests, optical microscopy (OM), scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS). The effects of the surface condition on ANC of copper tube were also investigated. Results showed that ANC of copper tube was a spontaneous process. The surface integrity of copper tube surface oxide layer is not the decisive factor of ANC. ANC originated from the dissolution of the surface oxide layer in HCOOH, which exposed fresh copper matrix. ANC is a special electrochemical corrosion, where the copper matrix acts as an anode and the undissolved surface oxide layer acts as a cathode due to the potential difference. The accumulation of corrosion products consisting of Cu(HCOO)₂ and Cu₂O can produce a wedge effect and generate many microcracks until to penetrate the copper tube wall. These findings would provide a deep understanding of the corrosion behavior of copper and copper alloys.     

Effect of direct current electric field on atmospheric corrosion behavior of copper under thin electrolyte layer

A thin layer electrochemical cell was successfully developed to study the atmospheric corrosion behavior of copper film in printed circuit board (PCB-Cu) under thin electrolyte layer (TEL) and direct current electric field (DCEF) by electrochemical impedance and electrochemical noise analysis. The electrochemical measurements and SEM morphologies after corrosion test indicate that DCEF decreases the corrosion of PCB-Cu under TEL. The corrosion rate and probability of pitting corrosion of PCB-Cu under DCEF decrease due to the electric migration of aggressive Cl⁻ ion out of working electrode surface.     

紫铜在清远乡村大气环境中的腐蚀行为

通过金相显微镜、扫描电镜、X射线衍射仪(XRD)、能量色散谱(EDS)和电化学阻抗谱(EIS),研究了紫铜在清远乡村大气环境中暴露不同时间后的腐蚀行为。结果表明:紫铜在清远乡村大气环境暴露后,有局部腐蚀发生。随着时间的延长,腐蚀产物增多,并逐渐覆盖了铜表面形成较为致密的膜层,导致腐蚀速率下降。在暴露的前6个月,紫铜的腐蚀产物主要是Cu_2O,随着时间的延长,大气中其他污染物对铜腐蚀的影响增加,12个月后腐蚀产物中出现了CuOHCl和CuS。     

Experimental and theoretical studies of cinnamyl alcohol as a novel corrosion inhibitor for copper foils in rolling oil

Cinnamyl alcohol (CA) was added to the rolling oil of copper foils as a novel corrosion inhibitor, and its anticorrosion performance and mechanism were studied using potentiodynamic polarization and electrochemical impedance spectroscopy. Microstructure and chemical composition of the copper electrode surface were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results showed that CA acted as a mixed-type inhibitor, and the maximum inhibition efficiency of 87.7% was achieved at 2.4 mM. Moreover, a protective film was formed on the copper surface, which attributed to the C–OH groups in the CA molecule. The absorption of CA on the copper surface was physisorption, which conformed to Langmuir adsorption isotherm, with a standard adsorption free energy of −11.38 kJ/mol. In the presence of CA, some flaky corrosion products changed into granular corrosion products. The synergistic effect of the granular corrosion products (copper chloride hydroxide) and the CA film further decreased the corrosion rate.     

The investigation of synergistic inhibition effect of rhodanine and iodide ion on the corrosion of copper in sulphuric acid solution

The synergistic inhibition effect of rhodanine (Rdn) and iodide ion on the corrosion of copper in 0.5 M H₂SO₄ solution was studied using electrochemical techniques. The surface morphologies of the substrates were examined by scanning electron microscopy (SEM). Elemental analysis of electrode surface exposed to test solution was determined by energy dispersive X-ray spectroscopy (EDX). It was found that Rdn provided satisfactory inhibition on the corrosion of copper. Moreover, its inhibition efficiency further increased in the presence of iodide ions due to synergistic effect. Finally, a mechanism of inhibition is proposed and discussed.     

Effects of alternating magnetic field on the corrosion rate and corrosion products of copper

The effects of alternating magnetic field on the corrosion morphologies, corrosion rate, and corrosion products of copper in 3.5% NaCl solution, sea water, and magnetized sea water were investigated using electrochemical test, scanning electron microscopy/energy dispersive analysis system of X-ray (SEM/EDAX), and X-ray diffraction (XRD). The results show that the corrosion rate of copper in magnetized sea water is minimal. Moreover, the surface of the specimen in magnetized sea water is uniform and compact as compared with those in 3.5% NaCl solution and sea water. The corrosion products of copper in magnetized sea water are mainly Cu2O and CuCl2. However, the corrosion products in sea water are CuCl, Cu2Cl(OH)3, and FeCl3·6H2O. The electrochemical corrosion mechanisms of copper in the three media were also discussed.     

镍/铜/锌多层镀层的制备及其耐蚀性

采用电沉积法在低碳钢基体上制备了镍/铜/锌多层镀层。采用扫描电镜观察镍/铜/锌多层镀层的微观结构;通过盐水(NaCl质量分数为5%)浸泡试验对制得的镍/铜/锌多层镀层进行耐蚀性评价;利用电化学阻抗谱(EIS)技术测试镍/铜/锌多层镀层在5%NaCl(质量分数)溶液中的电化学性能。结果表明:底层镍镀层颗粒以四角锥型交错堆积,中间层铜镀层颗粒以圆胞型结构沉积,表层锌镀层的表面平整致密,无明显孔隙;镍/铜/锌多层镀层具有较好的耐蚀性,电化学阻抗达到了5 623Ω·cm2,耐盐水浸泡时间可达2 880h时,是相同厚度单一镀层耐盐水浸泡时间的5~8倍。     

The effect of adatoms on the corrosion rate of copper

On the premises that corrosion is a surface process and adatoms modify the electronic states of the surface, the influence of Zn, Sn, S, I, F, Ta, Sb, Ti, Bi and Cr adatoms on the corrosion rate of copper was investigated. Adatoms were adsorbed at open-circuit from a solution containing 1.0×10⁻² mol l⁻¹ of the ions of the adatom element. The coverage of the adatoms at the surface was calculated by integration of the area under one of the peaks on the voltammogram of the copper electrode before and after dosing the electrode with the adatom. A significant difference in adsorbability of the adatoms at copper surface was observed. This difference was inter alia attributed to atomic size, crystallographic and kinetic effects. The surface properties were characterized by cyclic voltammetry, and for selected systems by SEM and electron microprobe. Corrosion of the surface in presence and in absence of the adatoms was followed by weight-loss method while surface oxidation, ‘surface corrosion’ was investigated by cyclic voltammetry and by electrochemical polarization techniques. The results showed that the nonmetals (F, S and I) markedly enhanced the rate of corrosion; Cr, Ta, Sb, Bi, Ti, Sn slightly enhanced the rate of corrosion of copper. Zinc, however, was the only element which decreased the rate of corrosion.     

Corrosion Mitigation of Copper in Acidic Chloride Pickling Solutions by 2-Amino-5-ethyl-1,3,4-thiadiazole

Corrosion of copper in acidic chloride pickling solutions of 0.5 M HCl and its mitigation by 2-amino-5-ethyl-1,3,4-thiadiazole (AETDA) have been investigated using potentiodynamic polarization, chronoamperometry, electrochemical impedance spectroscopy (EIS), and weight-loss measurements. The study was also complemented by scanning electron microscopy (SEM), energy dispersive x-ray (EDX), and UV-Visible absorption spectroscopy investigations. The presence of AETDA and the increase of its concentration in the chloride solutions greatly decreased the corrosion rate and increased the surface and polarization resistances of copper as indicated by the electrochemical measurements. Weight-loss data also indicated that AETDA decreases the dissolution of copper coupons in the studied chloride solution. SEM/EDX investigations showed that AETDA molecules are strongly adsorbed onto copper surface. The UV-Visible absorption spectra confirmed that AETDA molecules suppress the corrosion of copper via their interactions with the copper surface via their adsorption then formation of AETDA-Cu complex.     

Synergistic effect of chloride and sulfite ions on the atmospheric corrosion of bronze

The effect of chloride along with sulfite ions on the atmospheric corrosion of bronze was investigated by using periodic wet‐dry tests, surface tension tests and electrochemical impedance measurements. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) were used to characterize the corrosion products. Both the electrochemical impedance measurements and surface tension tests agreed well with the results of weight loss measurements. Synergistic effect of chloride and sulfite ions was observed during the whole process. In addition, we found that the attack of anions on the metal at the initial corrosion stage showed good agreement with their surface activity. However, as the corrosion proceeded, the interaction among the corrosion products induced by chloride and HSO₃^? accelerated the corrosion process. A scheme was given to explain the whole corrosion process.     

Sulfathiazole as potential corrosion inhibitor for copper in 0.1 M NaCl

Effects of sulfathiazole (ST) on copper corrosion as a corrosion inhibitor in 0.1 M NaCl solutions have been studied using potentiodynamic polarization, open circuit potential, electrochemical impedance spectroscopy with scanning electron microscopy (SEM). Potentiodynamic polarization measurements indicated that the presence of ST in chloride solutions affects mainly the cathodic process and decreases the corrosion current and shifts the corrosion potential towards more negative values. The adsorption of inhibitor on the copper surface obeys the Langmuir adsorption isotherm. The adsorption free energy of ST on copper (?33.47 kJ/mol) shows a strong adsorption of the inhibitor on the metal surface. The effect of temperature on the inhibition efficiency of sulfathiazole was examined with Arrhenius equation and activation energies in 0.1 M NaCl with and without inhibitor were calculated. Impedance data were analyzed using an appropriate equivalent circuit model for the electrode /electrolyte interface. SEM measurements also exhibited that the ST molecules are strongly adsorbed on the copper surface.     

湿度对Q235钢在污染土壤中腐蚀行为的影响

利用极化曲线技术、电化学阻抗测试技术、扫描电镜和表面能谱等方法,研究了Q235钢在不同湿度的污染土壤中的腐蚀行为。试验结果表明,湿度对Q235钢腐蚀的影响显著。随土壤湿度的增加,Q235钢在污染土壤中的腐蚀速率也增加,当含水量增大到20%时,腐蚀速率达到最大,然后腐蚀速率随着湿度增加而减小。Q235钢在湿度为20%的污染土壤中腐蚀后表面出现明显的裂痕和腐蚀坑。     

镍基超疏水表面的制备及其在海洋腐蚀防护中的应用

采用电化学沉积-表面修饰两步法在金属铜表面制备了镍基仿荷叶超疏水表面,采用扫描电子显微镜、X-射线衍射、X-射线光电子能谱、接触角测量仪等测试手段表征了所制备膜层的微观形貌、组成及润湿性,并基于Cassie模型理论分析了表面的润湿性与微观形貌间的相关性。在此基础上,采用电化学测试手段评价了所制备镍基超疏水膜在3.5%NaCl溶液中的腐蚀防护性能。结果表明:镍基超疏水膜可有效抑制金属基体的腐蚀过程,并提出了相应的腐蚀防护机制。     

铜在雨水中的腐蚀行为电化学研究

采用电化学动电位扫描和交流阻抗研究了铜在模拟斯 德哥尔摩雨水中的腐蚀行为.铜表面存在少量腐蚀产物时，铜在雨水中的腐蚀主要由电化学 机制控制；随着腐蚀产物在铜表面的大量生成和沉积，存在腐蚀产物的区域和不存在腐蚀产 物的区域，形成了电偶腐蚀电池，腐蚀产物区为阴极.     

The effect of purine on the corrosion of copper in chloride solutions

The influence of the concentration of purine (PU) on the corrosion and spontaneous dissolution of copper in 1.0 M NaCl solutions (pH 6.8) was studied. The investigations involved electrochemical polarization methods as well as weight-loss measurements, electrochemical quartz crystal microbalance (EQCM) techniques and scanning electron microscopy (SEM). The inhibition efficiency (IE) increases with an increase in the concentration of PU. An adherent layer of inhibitor is postulated to account for the protective effect. The adsorption of PU has been found to occur on the surface of copper according to the Langmuir isotherm. Purine is chemically adsorbed on the copper surface.     

Synthesis and corrosion protection study of poly(o-ethylaniline) coatings on copper

Poly(o-ethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethylaniline in an aqueous salicylate solution by using cyclic voltammetry. The characterization of these coatings was carried out by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of o-ethylaniline to generate strongly adherent and smooth poly(o-ethylaniline) coatings on Cu substrates. The performance of poly(o-ethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of these studies demonstrate that the poly(o-ethylaniline) coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.078 V versus SCE more positive in aqueous 3% NaCl for the poly(o-ethylaniline) coated Cu (∼ 15 μm thick) than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 70.