Probing Localised Corrosion Inhibition of AA2024-T3 by Integrating Electrode Array, SVET, SECM, and SEM-EDS Techniques

Abstract

This work demonstrates an approach towards the understanding of multi-scale and open-circuit localised electrochemical processes of AA2024-T3 in the presence and absence of an environmentally friendly rare-earth inhibitor; cerium diphenyl phosphate (Ce(dpp)3). At high temporal resolution, a wire bean electrode (WBE) made from 100 identical AA2024-T3 wires revealed sudden increases in galvanic anodic and cathodic activities immediately after dosing of 50 and 100 ppm of the inhibitor and an overall suppression of macro-scale activities by increasing the inhibitor concentration to 200 ppm, suggesting it as a fast-screening tool for inhibitors and measuring inhibition efficiency. At high spatial resolutions, scanning probe electrochemical techniques confirmed local activation of corroding microstructures on individual AA2024-T3 wires similarly by dosing the inhibitor up to 100 ppm. In agreement with WBE findings, the effective shutdown of both anodic and cathodic activities occurred after increasing the inhibitor concentration to 200 ppm confirming the optimal concentration of the Ce(dpp)3 and the mixed mode inhibition mechanism of this selected inhibitor on AA2024-T3.

Keywords

• localised corrosion and inhibition
• wire beam electrode (WBE)
• scanning vibrating electrode technique (SVET)
• scanning electrochemical microscopy (SECM)
• scanning electron microscope (SEM)