Corrosion inhibition alternatives and a novel chromate-like option: Review

Hexavalent chromium has dominated the corrosion inhibitor’s market as a benchmark alternative due to its unparalleled excellent corrosion inhibition properties. However, it was phased out because of its carcinogenic effects. Subsequently, many alternative inhibitors have been introduced into the inhibitor’s market but failed to meet the performance of this benchmark inhibitor. Recently, intelli-ion (AX1) was reported as a new alternative to hexavalent chromium based on Scanning Kelvin Probe (SKP) carried out on hot-dip galvanized steel (HDG) substrates for chromate and intelli-ion inhibitors. The intelli-ion system showed impressive performance at generation 1, with increased protection offered by the generation 2 product, showing no visible failure after 4 days test procedure. To further validate this, the cut edge corrosion performance of intelli-ion (AX1) and benzotriazole (BTA) was studied on galvanized steel specimen in 5wt.% NaCl solution using Scanning Vibrating Electrode Technique (SVET). From the SVET current density maps of AX1 (specimen A and B) vs. BTA (specimen C) after 24 h in 5 wt.% NaCl solution. The AX1 inhibitor had a better overall cut edge corrosion inhibition performance than the BTA.