Inhibitors for long-term protection are substances with low water solubility. The commercially available products are either used as a replacement for traditional anticorrosive pigments as the sole inhibitor or in combination with pigments to synergistically enhance anodic protection. Their use in coatings is expected to increase with rapid development of waterbased anticorrosive paints, in which some of the traditional anticorrosive pigments have limitations of compatibility and lower efficiency. Their usage level is higher than that of flash-rust inhibitors but markedly lower than anticorrosive pigments.
Typical examples of commercially used inhibitors are amine/zirco- nium complexes of toluylpropionic acid, zinc salts of 5-nitroisophtha — lic acid, zinc salts of cyanuric acid, zinc and magnesium salts of dodecylnaphthalenesulfonic acid and 2-mercaptobenzothiazolyl — succinic acid (Figure 5.24), and metal salts of aminocarboxylates.