Inhibition of Brass (80/20) by 5-Mercaptopentyl-3-Amino-1,2,4-Triazole in Neutral Solutions

Abstract

Abstract:The effect of the adsorption of 5-mercaptopentyl-3-amino-1,2,4-triazole (MPATA) on the corrosive behavior of brass (Cu80/Zn20) in neutral (pH 7.4) borate buffer solutions with and without 0.01 M NaCl was studied. Electrochemical methods show significant decrease of the anodic and cathodic currents on the polarization curves in the presence of MPATA. X-ray photoelectron spectroscopy (XPS) reveals MPATA adsorption on the brass surface from an inhibitor solution. After 17 h of exposure, a mixed complex [Cu x Zn y MPATA z ] with a thickness of about 3-3.5 nm is formed on the surface. This nanolayer has sufficient protective ability to withstand corrosion tests in a salt fog chamber: after 5 days of testing, the samples remain glossy and less than 1% of the surface has been damaged. After corrosion tests in a salt fog chamber, the surface of unprotected samples is enriched with zinc, while at the surface of inhibitor-treated samples, the copper and zinc are present in practically equal contents.

Corrosion of α-Brass in Solutions Containing Chloride Ions and 3-Mercaptoalkyl-5-amino-1H-1,2,4-triazoles

“…This is also demonstrated by the presence of oxygen. The increase in the oxygen concentration on the brass surface in the presence of the inhibitor is observed because of the formation of a multicomponent passive film, which includes ZnO•xH 2 O, Cu 2 O, and CuO oxides [5,[14][15][16], together with sparingly soluble complex compounds of zinc and copper with molecules of the studied inhibitors [67][68][69]. The results of the analysis of the elemental composition of the surface layer of the brass electrode before and after anodic polarization are given in Table 4.…”

“…Reference [66] demonstrates that mono-and poly-molecular chemisorption of 5-alkylmercapto-3-amino-1,2,4-triazoles on an oxidised Cu-electrode passivate copper very effectively. The protective effect of 5-alkylmercapto-3-amino-1,2,4-triazoles in a neutral chloride-borate buffer solution is most probably accounted for by the adsorption of the inhibitor from the solution and the formation of a protective nano-layer of sparingly soluble complex compounds, both on copper [67] and on Cu-20Zn brass [68]. The critical role of the complex formation in the passivation of Cu-20Zn brass in solutions containing various aggressive anions and a 2-mercaptobenzothiazole additive was proved in [69].…”

Time‐of‐flight secondary ion mass spectrometry and X‐ray photoelectron spectroscopy study of 2‐phenylimidazole on brass

“…It is commonly employed in condensers and cooling systems, heat exchangers, distillation plants, for valve construction, in the arts, shipbuilding, condenser thermal power generating units, marine engineering, different fields of mechanical engineering, and medical applications. [20][21][22][23][24][25][26][27][28][29][30] It has moderate corrosion resistance, but it corrodes severely in chloride solutions. [31][32][33][34] This work presents the first use of 2-phenylimidazole (PhI, Figure 1) as a corrosion inhibitor for brass in chloride solution.…”

“…In industry, brass is a very important alloy due to its good machinability and thermal and electrical conductivity. It is commonly employed in condensers and cooling systems, heat exchangers, distillation plants, for valve construction, in the arts, shipbuilding, condenser thermal power generating units, marine engineering, different fields of mechanical engineering, and medical applications 20–30 . It has moderate corrosion resistance, but it corrodes severely in chloride solutions 31–34 …”

Corrosion Inhibition

“…They demonstrate the potential of this approach for characterising pertinent interfaces in situ at the atomic scale, and describe the advantages and limitations of such measurements. Arkhipushkin et al [2] report their recent work on the inhibition of brass (Cu/Sn alloy) through the addition of a triazole-type compound to aqueous sodium chloride. Employing a combination of electrochemical measurements and X-ray photoelectron spectroscopy (XPS), they are able to gain insight into the functionality of the inhibitive species.…”