The influence of the amino group in 3‐amino‐1,2,4‐triazole corrosion inhibitor on the interface properties for brass studied by ToF‐SIMS

Rationale The detailed surface analysis of corrosion inhibitor surface layers by the application of 1,2,4‐triazole (TRI) and 3‐amino‐1,2,4‐triazole (3‐AT) compounds adsorbed from a 3 wt. % NaCl solution on the brass surface was performed by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). The results obtained were additionally supported by X‐ray photoelectron spectroscopy (XPS) measurements. Methods The description of the corrosion inhibitor surface layers was elaborated by using ToF‐SIMS and molecular‐specific signals. Characteristic molecular‐specific signals were used to perform 2D ToF‐SIMS imaging and cooling/heating experiment associated with ToF‐SIMS measurements. A detailed surface analysis using high‐resolution angle‐resolved XPS and gas cluster ion beam sputtering in combination with XPS measurements was also carried out. Results Organometallic complexes were formed after the corrosion process of brass with the release of Cu and Zn ions that subsequently connect with TRI or 3‐AT. Using ToF‐SIMS, possible spectral interferences of the organometallic species were considered due to the presence of different organometallic compounds composed of the two main Cu and Zn isotopes, that is, 63Cu and 65Cu and 64Zn and 66Zn. Using the molecular‐specific signals, 2D imaging was performed, which showed a different distribution of different species on the brass surface. In addition, a ToF‐SIMS experiment on thermal stability showed that most of the TRI‐ and 3‐AT‐related species desorb from the brass surface at 460 °C and 405 °C, respectively. Conclusions ToF‐SIMS analysis confirmed the formation of Cu/Zn‐ or Cu2‐inhibitor organometallic complexes, whereas the formation of Zn2‐inhibitor organometallic complexes on the brass surface was not confirmed. ToF‐SIMS imaging showed complete coverage of the brass surface with different Cu/Zn‐ or Cu2‐inhibitor organometallic complexes. The high thermal stability of the corrosion inhibitor surface layers was confirmed by ToF‐SIMS.