Synthesis of a new organic ionic liquid derived from thiazole thione: application against the corrosion of archaeological bronze with and without a patina layer in 3% NaCl

The protection of archaeological objects, particularly bronzes displayed in museums, remains indispensable due to the cultural value of these objects. Our objective is to choose a suitable protection system, particularly non-toxic corrosion inhibitors. Our choice was an organic ionic liquid based on thione triazole. In this work, we synthesized, characterized, and identified an ionic liquid derived from 3-phenyl-1,2,4-triazole 5-thione, denoted as PSTNHET, using the reflux heating method. Next, we studied its inhibitory effect on a Roman bronze sample (B66) with a clean surface using stationary and transient electrochemical methods, then we evaluated its protective power on a patinated bronze whose composition is similar to that of real archaeological bronzes dated to the Roman period.According to the results, the product PSTNHET, which was selected as an inhibitor, significantly reduces the corrosion of clean or patinated bronze surfaces in an environment that is naturally chlorinated. The development of a low-value current plateau and the emergence of a high-frequency loop ascribed to the creation of a protective coating are two signs of its influence. Its ability to adsorb the product on the metal surface and create a barrier against aggressive ions can be explained by this. The results obtained are encouraging, allowing us to apply it to real archaeological objects and offering promising prospects against metal corrosion, highlighting the effectiveness of the organic ionic liquid PSTNHET as a new environmentally friendly inhibitor.