Rapid Discovery of Corrosion Inhibitors and Synergistic Combinations Using High-Throughput Screening Methods

One approach to accelerate the discovery process of experimentally determined products is through the use of high-throughput screening (HTS) methods. This paper presents a method for the rapid screening of potential corrosion inhibitors and their synergistic combinations for aluminum alloy (AA)2024 (UNS A92024). The inhibition characteristics of 50 separate chemistries were assessed simultaneously within 9 h of testing using direct current (DC) polarization applied between two AA2024 wire electrodes and a multiple-electrode testing system. DC tests were conducted on single and binary combinations of the following inhibitors: cerium chloride (CeCl₃), yttrium chloride (YCl₃), sodium metatungstate (NaWO₄·3WO₄), sodium metavanadate (NaVO₃), lanthanum chloride (LaCl₃), sodium molybdate (Na₂MoO₄), sodium meta-silicate (Na₂SiO₃), potassium phosphate (KH₂PO₄), sodium phosphate (Na₃PO₄), and barium metaborate (BaB₂O₄). Testing was performed at 3.4 mM total inhibitor concentration in 0.6 M sodium chloride (NaCl) adjusted to pH 7. A comparison of HTS results to target electrochemical impedance results previously acquired over 10 days of testing yielded a high correlation (R² = 0.86). Testing of the inhibitor combinations revealed both synergistic and antagonistic pairings. This experimental approach provides an avenue for the rapid discovery and performance characterization of effective corrosion inhibitors in an array of conditions using combinatorial methods.