High-Throughput Assessment of Inhibitor Synergies on Aluminum Alloy 2024-T3 Through Measurement of Surface Copper Enrichment

The identification of new corrosion inhibition systems remains dependent on experimentation for screening and characterization. One approach for the acceleration of this discovery process is through the use of high-throughput methods. This paper examines the measurement of surface copper enrichment as a method for the rapid and high-throughput screening of corrosion inhibitors and their combinations for aluminum alloy 2024-T3 (AA2024-T3). Ninety-six AA2024-T3 wire electrodes were assembled in a reaction frame with 2-mL cells and exposed to 0.6 M sodium chloride (NaCl) containing 3.4 mM total inhibitor concentration adjusted to pH 7. Eleven single inorganic chemical species were evaluated for corrosion inhibition: sodium chromate (Na2CrO4), sodium metavanadate (NaVO3), cerium chloride (CeCl3), barium metaborate (BaB2O4), yttrium chloride (YCl3), sodium metatungstate (Na2WO4-3WO3), potassium phosphate (KH2PO4), lanthanum chloride (LaCl3), sodium metasilicate (Na2SiO3), sodium phosphate (Na2PO4), and sodium molybdate (Na2Mo4). These high-throughput methods also allowed the evaluation of 44 binary combinations of these species for possible synergy between the species. The synergistic combinations of molybdate with rare earth metal cations cerium, yttrium, and lanthanum were found to rival the corrosion mitigation of sodium chromate based on the evaluation of surface copper enrichment.