Corrosion inhibition of copper in tetra‐n‐butylammonium bromide aqueous solution by benzotriazole

The corrosion inhibition behavior of benzotriazole (BTA) on copper in 17 wt% tetra‐n‐butylammonium bromide (TBAB) aerated aqueous solution was investigated by weight‐loss tests, potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electron microscopy/energy dispersive X‐ray spectroscopy. BTA is a good inhibitor in 17 wt% TBAB solution. The inhibition efficiency of BTA increases with increasing inhibitor concentration, attaining efficiencies of up to 90% calculated according to different methodologies. Adsorption of BTA in 17 wt% TBAB solution on the copper surface was found to obey the Langmuir adsorption isotherm.     

Corrosion inhibition of copper–phosphorus brazing alloys in tetra‐n‐butylammonium bromide aerated aqueous solution by benzotriazole

The corrosion inhibition behavior of benzotriazole (BTA) on a brazing alloy, CuP in the non‐welded and welded conditions in 17 wt% (0.534 mol/L) tetra‐n‐butylammonium bromide (TBAB) aerated aqueous solution was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy/energy dispersive X‐ray spectroscopy techniques. The experimental results showed that BTA could protect effectively copper alloys in aqueous TBAB solution. The inhibition efficiency of BTA increased with increasing inhibitor concentration from 0.1 to 6 g/L, attaining efficiencies of up to 96% calculated according to different methodologies. Corrosion current densities were lower after the melting process. Galvanic studies showed that copper behaved as the anode when coupled to its alloys. The addition of BTA caused an increase in charge transfer resistance and a decrease in the capacitance of the double layer. Adsorption of BTA in 17 wt% TBAB solution on the copper alloys' surface was found to obey the Langmuir adsorption isotherm.     

Corrosion study of copper in the presence of benzotriazole and its hydroxy derivative

The inhibitory properties of benzotriazole (BTAH) and its hydroxy derivative, 1‐hydroxy‐benzotriazole (BTAOH) on copper corrosion, were compared in 3% NaCl solution using cyclic voltammetry (CV), immersion tests, profilometry and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDX). CV experiments showed rapid interaction of both inhibitors with a Cu surface, but only at high concentrations. Immersion tests under stationary conditions showed that BTAOH offered corrosion protection only at concentration of 10 mM. Moreover, it was not effective under stirring conditions at any of the concentrations investigated. In contrast, BTAH exhibited good corrosion inhibition ability in all immersion tests. BTAOH, at up to 1 mM, increased the surface roughness of Cu more than 3% NaCl solution alone, but a significant reduction of surface roughening was observed when BTAH was present. Porous cross‐linked acicular structures and star‐like structures were observed using SEM/EDX in the case of BTAOH treatment. When Cu was treated with BTAH, roundish surface structures composed of bent plates with toothed‐like edges, acicular structures and non‐porous few hundred nm thick plates were observed.     

Studies on corrosion inhibition of copper by alkanethiol SAMs prepared in aqueous micellar solution

The character of 1‐dodecanethiol (DT) self‐assembled monolayers (SAMs) formed on copper surface in aqueous micellar solution is investigated by means of contact angle measurement, electrochemical impedance spectroscopy (EIS), and polarization curves. The contact angle measurement shows that the SAMs formed in aqueous micellar solution are oriented and compact. According to the electrochemical measurements, it is found that both the concentration of DT and temperature can significantly affect the property of SAMs. The DT SAMs can prevent the corrosion of copper in chloride‐containing solution effectively because the inhibition efficiency can reach 99.59% at the DT concentration of 10^?2 M . The adsorption of DT in aqueous micellar solution obeys to the Langmuir adsorption isotherm, and the value of the free energy of adsorption calculated indicates that the adsorption of DT molecule is a spontaneous process and a typical of chemical adsorption.     

Corrosion inhibition of zinc in tetra-n-butylammonium bromide aerated aqueous solution by benzotriazole and Na3PO4

The effect of benzotriazole (BTA), Na₃PO₄ and their mixture on the corrosion of zinc in 17 wt.% (0.534 mol l⁻¹) tetra-n-butylammonium bromide (TBAB) aerated aqueous solution has been investigated by means of weight-loss test, potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS) and SEM/EDX techniques. The experimental results showed that BTA or Na₃PO₄ or inhibitor mixture could protect zinc in aqueous TBAB solution. The inhibitor combinations led to higher efficiencies compared to those obtained when added individually. An inhibition efficiency of an inhibitor mixture consisting of 0.5 g l⁻¹ BTA and 1 g l⁻¹ Na₃PO₄ was more than 97%.     

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.     

Corrosion inhibition of carbon steel in tetra-n-butylammonium bromide aqueous solution by benzotriazole and Na3PO4

The corrosion inhibition behavior of benzotriazole, Na₃PO₄ and their mixture on carbon steel in 20 wt.% (0.628 mol l⁻¹) tetra-n-butylammonium bromide aerated aqueous solution was investigated by weight-loss test, potentiodynamic polarization measurement, electrochemical impedance spectroscopy and scanning electron microscope/energy dispersive X-ray techniques. The inhibition action of BTA or SP or inhibitors mixture on the corrosion of carbon steel is mainly due to the inhibition of anodic process of corrosion. The results revealed that inhibitors mixtures have shown synergistic effects at lower concentration of inhibitors. At 2 g l⁻¹ BTA and 2 g l⁻¹ SP showed optimum enhanced inhibition compared with their individual effects.     

黄铜在含磷酸二氢钠或硅酸钠的铝酸盐电解液中的等离子电解氧化行为和耐腐蚀性能（英文）

采用等离子电解氧化(PEO)技术对黄铜进行表面处理,研究其在铝酸盐电解液中分别加入NaH₂PO₄ (S1)和Na₂SiO₃(S2)添加剂对涂层形成和耐腐蚀性能的影响。在S1电解液中进行PEO处理的初始阶段,黄铜表面形成AlPO₄和Al₂O₃的混合涂层,导致快速产生等离子体火花放电现象并形成由Al₂O₃、CuO、Cu₂O和ZnO组成的黑色涂层。然而,在S2电解液中,等离子体火花放电行为延迟产生。由于产生较多的Cu₂O,S2涂层显示为深红棕色。Mott-Schottky测试表明,S1涂层为p型半导体;S2涂层具有n型和p型半导体可调性。动电位极化和电化学阻抗谱(EIS)测试表明,PEO处理能显著提高黄铜的耐腐蚀性,腐蚀防护效率可达91.50%,S1涂层电荷转移电阻最大可达59.95 kΩ·cm²。     

Adsorption and corrosion inhibition of phytic acid calcium on the copper surface in 3 wt% NaCl solution

The adsorption and corrosion protection effect of phytic acid calcium (PAC) film on the copper surface in 3 wt% NaCl solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Raman spectroscopy. Polarization curves indicate that PAC is a mixed inhibitor, affecting both cathodic and anodic corrosion currents. The inhibition efficiency of PAC film reached 92.53% at an optimized condition. Adsorption of PAC molecules on the surface followed Langmuir adsorption isotherm and the standard Gibbs energy of −37.32 kJ mol⁻¹ indicated a chemisorptive way. Raman studies suggested that PAC molecule chemically anchored at the surface via PO groups.     

Effect of serine, threonine and glutamic acid on the corrosion of copper in aerated hydrochloric acid solution

The corrosion inhibition of three amino acid compounds on copper was investigated by electrochemical method. They suppressed cathodic current densities and shifted the corrosion potential towards more negative values. The interaction between amino acid and copper surface was certified by reflected FT-infrared spectroscopy. The quantum chemical parameters were obtained by PM3 semi-empirical calculation. Glutamic acid has the smaller net positive charge of nitrogen atom and the more net negative charge of oxygen atoms. The improved inhibition of glutamic acid was due to the stabilization of its adsorption on the copper surface by the oxygen atoms in its structure.     

The synergistic effect of anions and the ammonium cation on the inhibition of iron corrosion in acid solution

The synergistic effect of various anions and the tetra-n-butylammonium cation on the inhibition of iron corrosion in 1 M HClO₄ and their joint adsorption on iron were studied by using an impedance and a polarization technique. Surface coverage obtained from double layer capacitance showed joint adsorption of the anion and cation on the iron surface. Assuming competitive adsorption of these ions at the interface, the synergism of corrosion inhibition and joint adsorption were estimated using a parameter calculated from the inhibition efficiencies and the surface coverages of the anion and/or cation. The synergistic effect was shown for all of the anions and cation examined.     

Electrochemical studies on the effect of (2E)‐3‐amino‐2‐phenylazo‐but‐2‐enenitrile and its derivative on the behaviour of copper in nitric acid

The objective of this work is to provide additional insight on the influence of (2E)‐3‐amino‐2‐phenylazo‐but‐2‐enenitrile and its derivative as corrosion inhibitors for copper in 0.5 M HNO₃. Electrochemical techniques (potentiodynamic polarization, polarization resistance and impedance spectroscopy) as well as weight loss measurements have been employed to study the corrosion inhibition. The investigated compounds have shown inhibition efficiency in 0.5 M HNO₃. Inhibition efficiency of these compounds has been found to vary with the concentrations of the compounds. The adsorption of these compounds on the copper surface from the acid solution has been found to obey Langmuir adsorption isotherm. The results revealed that the compounds are mixed type inhibitors. The effect of temperature on the inhibition efficiency was studied.     

The inhibitive effect of 5‐amino‐indole on the corrosion of mild steel in acidic media

The inhibitor performance of 5‐aminoindole (5‐AI) on mild steel corrosion in 0.5 M HCl was investigated in relation to the inhibitor concentration using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization (LPR) methods. The effect of immersion time on the corrosion behavior of mild steel was also studied. The impedance data obtained were fitted and modeled using an equivalent circuit model. The results show that 5‐AI is an effective inhibitor and has an inhibition efficiency of 90% at 1 × 10^?2 M additive concentration. The adsorption behavior of 5‐AI was also investigated. For this purpose, the adsorption equilibrium constant (K_ads), and the free energy of adsorption (ΔG_ads) were calculated and discussed. It was found that 5‐AI acts as mixed‐type inhibitor and obeys Langmuir adsorption isotherm with a free energy of adsorption of ?27.71 kJ/mol.     

Investigation of the inhibition effect of indole-3-carboxylic acid on the copper corrosion in 0.5 M H2SO4

Inhibition of the copper corrosion by means of indole-3-carboxylic acid (ICA), was studied in 0.5 M H₂SO₄ solutions in the temperature range from 25 °C to 55 °C using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained from the both measurement techniques revealed good inhibitor efficiency in the studied concentration range. Nyquist plots showed depressed semicircles with their centre below real axis. Moreover, the impedance spectra in the case of both non inhibited solutions and inhibited ones by means of lower inhibitor concentrations exhibited Warburg impedance. The adsorption behaviour of ICA followed Langmuir’s isotherm.     

Evaluation of inhibitors and biocide on the corrosion control of copper in neutral aqueous environment

Polarisation and impedance measurements were performed on copper in neutral aqueous solution with and without inhibitors and biocide. The inhibitors used were 3-benzylidene amino 1,2,4-triazole phosphonate (BATP), 3-cinnamalidene amino 1,2,4-triazole phosphonate (CATP), 3-salicylalidene amino 1,2,4-triazole phosphonate (SATP) and 3-paranitro benzylidene amino 1,2,4-triazole phosphonate (PBATP). Effect of inhibitors and biocide against the corrosion of copper in neutral aqueous solution has been studied. Results elucidate the minimal interference between biocide and inhibitors system. Surface evaluation techniques like FT-IR, XRD and EDXA were used to determine the nature of the protective film formed on the metal surface.     

Synergistic inhibition effect of 6-benzylaminopurine and iodide ion on the corrosion of cold rolled steel in H3PO4 solution

The synergistic inhibition effect of 6-benzylaminopurine (BAP) and iodide ion (I⁻) on the corrosion of cold rolled steel (CRS) in 1.0 M H₃PO₄ solution was studied by weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The results show that BAP has a moderate inhibitive effect. However, incorporation of BAP with I⁻ improves the inhibition performance significantly. The adsorption of BAP in the absence and presence of I⁻ obeys Langmuir adsorption isotherm. BAP and BAP/I⁻ mixture act as mixed-type inhibitors. A probable synergism mechanism is proposed.