Investigation of inhibiting properties of self-assembled films of 4-aminothiophenol on copper in 3.5% NaCl

A self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) was formed on copper surface which was characterized using cyclic voltammetry, Fourier transform infrared spectroscopy, and Raman spectroscopic techniques. The surface morphology of the monolayer was examined by scanning electron microscopy. The anticorrosive property of the SAM was investigated using electrochemical impedance spectroscopy and polarization studies. The electrochemical measurements showed that the inhibition efficiency increased with the immersion time of copper in ethanolic solution of 4-ATP in 3.5% NaCl. The significant corrosion protection efficiency of SAM could be due to the compact and dense monolayer on metallic surfaces.     

Surface protection of copper in aerated 3.5% sodium chloride solutions by 3-amino-5-mercapto-1,2,4-triazole as a copper corrosion inhibitor

Surface protection of copper in aerated 3.5% NaCl solutions by 3-amino-5-mercapto-1,2,4-triazole (AMTA) has been reported. The study has been carried out using weight loss, pH, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) measurements along with scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) investigations. Weight-loss data indicated that the dissolution rate and the pH of the solution decreased to a minimum after 24 days of copper immersion due to the inhibitive action of AMTA. PDP, CA, and EIS measurements showed that AMTA decreased the corrosion rates and increased the polarization resistance and inhibition efficiency. This effect was increased with increasing AMTA concentration as well as the immersion time of the copper electrode to 50 h before measurements. SEM micrograph and EDS analysis proved that the inhibition of copper corrosion takes place due to adsorption of AMTA onto the surface. These results together confirmed that AMTA is a good mixed-type inhibitor and the inhibition of copper corrosion is achieved by strong adsorption of AMTA molecules.     

Copper/polypyrrole multilayer coating for 7075 aluminum alloy protection

The corrosion behavior of 7075 aluminum (Al), copper modified Al (Al/Cu), polypyrrole modified Al (Al/PPy) and copper (under layer)/polypyrrole (top layer) modified Al (Al/Cu/PPy) samples were investigated in 3.5% NaCl solution. The copper plating on aluminum was carried out from acidic copper sulphate solution by electroless method. Polypyrrole (PPy) was electrochemically synthesized on Al and Al/Cu electrodes from 0.1 M pyrrole containing 0.4 M oxalic acid solution using cyclic voltammetry technique. The films synthesized were characterized by Fourier transform infrared spectroscopy (FT-IR). The thermal stability of PPy films was investigated by thermogravimetric analysis (TGA). The surface morphologies were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion behavior of samples was investigated by electrochemical impedance spectroscopy (EIS) and anodic polarization curves. The data obtained showed that the synthesis of PPy on top of the Cu layer significantly enhances the corrosion resistance of Al by exhibiting a barrier effect against the attack of corrosive environment.     

A robust method of enhancement of corrosion inhibitive ability of electrodeposited poly-3-amino-5-mercapto-1,2,4-triazole films over copper surface using graphene oxide

Abstract

A simple and new strategy has been developed to protect metallic copper by forming composite material using graphene oxide (GO) and electropolymerised p-3-amino-5-mercapto-1,2,4-triazole (p-AMTa). The structure and the mechanism of the formation of the polymer and polymer composite were predicted from Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopic (XPS) analysis and Energy Dispersive X-ray (EDX) spectroscopy. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDS) were employed to study the corrosion inhibitive action of p-AMTa?+?GO composite in 3.5% NaCl medium. The study revealed that, the copper electrode modified with the carbon based polymeric composite suppressed the anodic dissolution of copper thereby increasing its corrosion resistance.     

Plant derived cationic dye as an effective corrosion inhibitor for 7075 aluminum alloy in 3.5% NaCl solution

The inhibition of the corrosion of 7075 aluminum alloy in 3.5 wt.% NaCl solution by 5,6-dihydro-9,10-dimethoxybenzo[g]-1,3-benzodioxolo[5,6-a]quinolizinium (berberine) has been studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM). Inhibition efficiency was found to increase with increasing concentration of berberine. The adsorption of the berberine on the 7075 aluminum alloy surface obeyed the Langmuir adsorption isotherm. The adsorbed film on 7075 aluminum alloy surface containing inhibitor was confirmed by the SEM, and SECM. The results obtained showed that the berberine could serve as an effective inhibitor of the corrosion of 7075 aluminum alloy in 3.5% NaCl.     

Enhanced corrosion resistance and mechanical properties of nanostructured graphene-polymer composite coating on copper by electrophoretic deposition

Composite coating of reduced graphene oxide (RGO) and poly (4-vinylpyridine-co-butyl methacrylate) (PVPBM) on copper was produced by electrophoretic deposition (EPD) technique. The structural and morphological characterizations of the RGO-PVPBM coating were carried out using a Raman spectrometer and a field emission scanning electron microscope, respectively. The thermal stability of the coating was analyzed by thermo-gravimetric analysis, and the corrosion resistance properties were examined by potentiodynamic polarization measurements and electrochemical impedance spectroscopy in 3.5% NaCl solution. At optimal EPD conditions of operating voltage of 5 V and total deposition time of 15 min, a uniform crack-free RGO-PVPBM composite coating is obtained. The microscratch experiment has shown an enhancement in the crack propagation resistance of RGO-PVPBM composite coating up to 3.7 times and adhesive strength increased ~2 times compared to PVPBM coating, thereby making it a potential damage tolerance surface coating on Cu substrate. The potentiodynamic measurements clearly show that RGO-PVPBM acts as a protective coating for Cu in 3.5% NaCl solution. The corrosion inhibition efficiency for RGO-PVPBM coating was calculated to be 95.4% which clearly indicates that the tailored RGO-PVPBM composite is an excellent barrier coating to ion diffusion and corrosive electrolyte with considerably enhanced corrosion resistance.     

Sweet aqueous solution for electrochemical synthesis of polypyrrole part 1B: On copper and its alloys

The electrochemical synthesis of polypyrrole (PPy) on copper and brass has been successfully achieved in sodium saccharinate and pyrrole aqueous medium. The synthesized coating under several electrochemical techniques such as cyclic voltammetry, galvanostatic and potentiostatic is homogeneous and adherent. PPy has been characterized by SEM, XPS, IR and Raman spectroscopy and its quality has been confirmed. The doping level obtained from N 1s XPS signal of the oxidized PPy depends on the electrochemical technique used to produce the film. The corrosion performance of PPy/copper and PPy/brass has been evaluated in 3% NaCl and 0.1 M HCl using linear polarization and electrochemical impedance spectroscopy. The results show that PPy coating electrodeposited from sodium saccharinate exhibits significant corrosion protection properties.     

Anticorrosion and electromagnetic interference shielding behavior of candle soot-based epoxy coating

This article presents candle soot (CS) as anticorrosion coating material for mild steel (MS) in 3.5 wt % of NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy. CS is easily available, low-cost material, and characterized by using X-Ray diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM). CS is superhydrobhobic in nature that helps to prevent corrosion by repelling water molecules from MS surface. The electrochemical results confirmed the prevention in corrosion process for MS using candle soot-epoxy (CS-EP) based anticorrosion coatings. The CS-based coatings displayed outstanding barrier properties in 3.5 wt % of NaCl solution in comparison to the neat EP coating. Different candle CS-EP coating combinations were tested that exhibited excellent corrosion inhibition performance with highest protection increased up to 98.45% at 0.2 wt % of CS. The surface morphological studies were used to analyze the MS surface conditions in absence and presence of CS-EP coating in 3.5 wt % of NaCl solution. CS-EP admixtures were also tested for their shielding effectiveness in the frequency range of 8.2–12.4 GHz and it has been found that on incorporation of 0.2 wt % of CS in EP resin total shielding effectiveness (SE_T) increased to −5.3 dB as compared to −0.33 dB for neat EP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48675.     

规整有机分子自聚集体对铜的高效缓蚀的研究

通过多步法合成了离子型含双苯并三氮唑环的目标分子,4,4'-{苯-1,3-二基二[(1E)-3-羰基丙-1-烯-1,3-二基]}二[2-(2H-苯并三唑-2-基)苯醇酸]二钾。在室温条件下,目标分子在3.5%（质量）NaCl/DMSO（二甲基亚枫）混合溶液 （体积比：40/60） 中能够发生分子自组装产生纳-微米级的自聚集体。通过傅里叶变换红外光谱 （FT-IR）、拉曼光谱和X射线光电子能谱 （XPS） 的表征,证实了所形成的目标分子自聚集体能够对铜表面产生强烈的化学吸附作用,在铜表面形成自组装膜。利用电化学方法测定了目标分子自聚集体吸附在铜表面形成自组装膜后,在3.5%（质量）NaCl溶液中的缓蚀性能。结果表明目标分子自聚集体在NaCl溶液中能高效地抑制铜腐蚀。     

Study on highly efficient corrosion inhibition of copper by regular self-aggregates of organic molecule

This study presents synthesis of target ionic bistriazole rings-based molecule, 4,4'-{benzene-1,3-diylbis[(1E)-3-oxoprop-1-ene-1,3-diyl]}bis[2-(2H-benzotriazol-2-yl)phenolate] dipotassium (BDBD), through multi-step preparation route. At room temperature, the target molecule can self-assemble to produce nano-micron self-aggregates in a 3.5%(mass) NaCl / DMSO (dimethyl maple) mixed solution (volume ratio, 40/60). It is shown that the predominantly strong chemical adsorption of the formed molecular self-aggregates on the studied copper specimen leads to the yield of self-assembly film on copper surface, which is characterized by FT-IR, Raman and XPS spectroscopy. The corrosion inhibition performance of the stable self-aggregates adsorbed-copper specimens in 3.5%(mass) brine solution based on electrochemical method is surveyed. The results show that the target molecular self-aggregates can effectively inhibit copper corrosion in NaCl solution.     

Effect of copper (II) acetate pretreatment on zinc phosphate coating morphology and corrosion resistance

Zinc phosphate coating is widely used for corrosion protection of metallic materials, mainly mild steel. In the present study, the effect of pretreatment with copper acetate solution on zinc phosphate layer properties was investigated via scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The corrosion resistance of the coating was evaluated using polarization curves and electrochemical impedance spectroscopy in an aerated 3.5% NaCl solution. The pretreatment resulted in a compact and uniform phosphate coating with smaller crystal size and greater surface coverage. Electrochemical results showed better corrosion resistance for the pretreated phosphate layer compared with the untreated one.     

Self-assembled 1-octadecyl-1H-1,2,4-triazole films on copper for corrosion protection

A film of 1-octadecyl-1H-1,2,4-triazole (OTA) was formed on a fresh copper surface by self-assembly technique. The optimum concentration of OTA and immersion time for the formation of a protective OTA film have been established using electrochemical impedance spectroscopy (EIS). These are (i) 15 mM concentration of OTA in methanol and (ii) immersion period of 48 h. X-ray photoelectron spectroscopy (XPS), reflection absorption FTIR spectroscopy, atomic force microscopy (AFM), and contact angle measurements have been used to characterize the OTA film on copper surface. The efficiency of OTA film to protect copper from corrosion in aqueous NaCl environment has been investigated using EIS, potentiodynamic polarization studies, cyclic voltammetry and weight-loss studies. All these studies showed that the OTA film affords excellent protection against corrosion of copper.     

The long-term effectiveness and failure mechanism of the chemically bonded phosphate ceramic coatings with different thickness

In this study, the chemically bonded phosphate ceramic coatings (CBPCs) with different thickness (100 µm, 200 µm, and 300 µm) are prepared on the mild steel (Q235). Potentiodynamic polarization testing and electrochemical impedance spectroscopy were carried out to study the synthetic effect of coating thickness and etching time (12, 24, 36, and 48 hours) on the corrosion behavior of CBPCs. The surface and cross section microstructure of CBPCs before and after different immersion time in 3.5 wt.% NaCl solution is investigated to better understand the corrosion behavior. Results revealed that the enhanced coating thickness can effectively postpone the corrosive factors infiltration into the substrate and prohibit the corrosion of the mild steel. From the potentiodynamic polarization testing results, the protection efficiency of the coating greatly increases with the increase in etching time. In addition, an increase in 10 000 and 1000 orders of magnitude of impedance value for the CBPCs with 12 hours and 48 hours etching time has been observed, respectively, indicating the CBPCs can effectively protect the mild steel from corrosion damage even with long-term service.     

Self-assembly on copper surface by using imidazole derivative for corrosion protection

This paper presents the self-assembly of 1-(3-aminopropyl) imidazole (API) monolayer on the copper surface to study the inhibition effect of the API against copper corrosion in 3% NaCl solution. The optimum concentration and assembling time for the assembly of API on copper were ascertained using electrochemical impedance spectroscopy (EIS). It was found that the API self-assembled monolayer (SAM) was formed with the concentration of 1.0 mM of API at 24 h assembling time and the maximum inhibition efficiency that could be achieved was 93.10%. The API SAM on copper was characterized by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurement (WCA). The presence of N and C signals in the XPS and EDX, show that the API molecules successfully anchor on the copper surface which demonstrates formation of API SAM on the copper surface. Corrosion protection capability of the copper modified with API was evaluated by the electrochemical polarization study (EPS) and scanning electron microscopy (SEM). The results of electrochemical and SEM analysis revealed that the API modified copper showed better corrosion protection in 3% NaCl solution.     

Zinc deposited polymer coatings for copper protection

Polypyrrole (PPy) and polyaniline (PAni) coatings were electrosynthesized on copper, by using cyclic voltammetry technique. Then, these coatings were modified with the deposition of zinc particles from aqueous zinc sulphate solution. The electrodeposition of zinc was achieved at a constant potential value of −1.20 V, in the amount of ∼0.75 mg/cm². The corrosion performance of zinc modified polymer coatings were investigated in 3.5% NaCl solution; by using the electrochemical impedance spectroscopy (EIS), and anodic polarization curves. The zinc particles improved the barrier property of polymer films, thanks to formation of voluminous zinc corrosion products within the pores of polymer coating. Also, the zinc particles provided cathodic protection to the substrate, where the polymer film played the role of conductance between zinc particles and copper.     

Electropolymerized polyaniline coatings on aluminum alloy 3004 and their corrosion protection performance

Homogeneous and adherent polyaniline coatings were electrosynthesized on aluminum (Al) alloy 3004 (AA 3004) from an aqueous solution containing aniline and oxalic acid by using the galvanostatic polarization method. A higher applied current density in the polymerization stage proved to be the best condition to adopt for the synthesis of more compact and strongly adherent polyaniline coatings on Al. The corrosion performances of polyaniline coatings were investigated in 3.5% NaCl solution by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS).Potentiodynamic polarization and electrochemical impedance spectroscopy studies reveal that the polyaniline acts as a protective layer on Al against corrosion in 3.5% NaCl solution. The current corrosion decreases significantly from 6.55 μA cm⁻² for uncoated Al to 0.158 μA cm⁻² for polyaniline-coated Al. The corrosion rate of the polyaniline-coated Al is found to be 5.17 × 10⁻⁴ mm year⁻¹, which is ∼40 times lower than that observed for bare Al. The potential corrosion increases from −1.015 V versus SCE for uncoated Al to ∼−0.9 V versus SCE for polyaniline-coated Al electrodes. The positive shift of ∼0.11 V in potential corrosion indicates the protection of the Al surface by the polyaniline coatings.The synthesized coatings were characterized by UV-visible absorption spectrometry, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Optical absorption spectroscopy reveals the formation of the emeraldine form of polyaniline. The results of this study clearly ascertain that the polyaniline has outstanding potential to protect the AA 3004 alloy against corrosion in a chloride environment.     

Improvement of the properties of AZ91D magnesium alloy by treatment with a molten AlCl3–NaCl salt to form an Mg–Al intermetallic surface layer

A process for surface modification of AZ91D magnesium alloy has been carried out in AlCl₃–NaCl molten salts melt at 573 K for 7 h. The process was used to form a diffusion alloying layer on the surface of the sample to improve corrosion resistance. The diffusion alloying layer was mainly composed of Mg–Al intermetallic compounds. The continued immersion test in 5% NaCl solutions displayed that molten salt diffusion-treated specimen had better corrosion resistance compared to the untreated AZ91D specimen. The polarization test indicated that the Mg–Al intermetallic compounds of the layer were an effective corrosion barrier to decrease the corrosion rate for AZ91D magnesium alloy when exposed to 3.5% NaCl solutions. The microhardness values of the Mg–Al intermetallic compounds were higher than those of the substrate.     

Corrosion protective poly(o-ethoxyaniline) coatings on copper

Poly(o-ethoxyaniline) (POEA) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethoxyaniline in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The performance of POEA 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 the potentiodynamic polarization and EIS studies demonstrate that the POEA coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.330 V versus SCE more positive in aqueous 3% NaCl for the POEA coated Cu than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 140.     

Evaluation of cysteine as environmentally friendly corrosion inhibitor for copper in neutral and acidic chloride solutions

The efficiency of cysteine as a non-toxic corrosion inhibitor for copper metal in 0.6 M NaCl and 1.0 M HCl has been investigated by electrochemical studies. Potentiodynamic polarization measurements and electrochemical impedance spectroscopy “EIS” were used to study the effect of cysteine on the corrosion inhibition of copper. Inhibition efficiency of about 84% could be achieved in chloride solutions. The presence of Cu²⁺ ions increases the inhibition efficiency to 90%. Potentiodynamic polarization measurements showed that the presence of cysteine in acidic and neutral chloride solutions affects mainly the cathodic process and decreases the corrosion current to a great extent and shifts the corrosion potential towards more negative values. The experimental impedance data were analyzed according to a proposed equivalent circuit model for the electrode/electrolyte interface. Results obtained from potentiodynamic polarization and impedance measurements are in good agreement. Adsorption of cysteine on the surface of Cu, in neutral and acidic chloride solutions, follows the Langmuir adsorption isotherm. The adsorption free energy of cysteine on Cu (−25 kJ mol⁻¹) reveals a strong physical adsorption of the inhibitor on the metal surface.     

Electrochemical synthesis of poly(o-anisidine) and its corrosion studies as a coating on aluminum alloy 3105

The synthesis of poly(o-anisidine) coatings on aluminum alloy 3105 (AA3105) surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by reflection absorption infrared (RAIR) spectroscopy, UV–visible absorption spectrometry and scanning electron microscopy (SEM). Optical absorption spectroscopy reveals the formation of the emeraldine form of poly(o-anisidine). The anticorrosion performances of poly(o-anisidine) coatings were investigated in 3.5% NaCl solution by the potentiodynamic polarization technique Tafle and electrochemical impedance spectroscopy (EIS). The corrosion rate of poly(o-anisidine)-coated AA3105 was found ∼330 times lower than bare AA3105 and potential corrosion increases from −0.85 V versus SCE for uncoated AA3105 to −0.65 V versus SCE for poly(o-anisidine)-coated AA3105 electrodes. The results of this study clearly ascertain that the poly(o-anisidine) has outstanding potential to protect the AA3105 against corrosion in a chloride environment.