Effect of delayed inhibitor supply on AA2024-T3 intermetallic activity: A local in situ analysis with reflected microscopy

• Published in: Corrosion science 2024-04, Vol.230, p.111910, Article 111910
• Main Authors: Mopon, Marlon, Mol, Arjan, Garcia, Santiago J.
• Format: Article
• Language: English
• Subjects: Corrosion inhibition; Difference imaging; Inhibitor deposition kinetics; Metallographic microscopy
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2024.111910

Understanding how late an inhibitor can be released once corrosion initiated without compromising corrosion protection may help in developing more efficient anticorrosion coatings. We explored this idea through time-controlled Ce(NO3)3 availability to AA2024-T3 immersed in 0.05 M NaCl. Ce(NO3)3 was supplied at 0, 30, 60, and 180 s from the start of immersion to get a concentration of 0.001 M. Detailed visualization of surface changes at the intermetallic particle level was obtained using in-situ reflected microscopy. SEM-EDX and confocal laser microscopy confirmed the extent of intermetallic degradation and local inhibitor deposition corresponding to operando changes. When the inhibitor is supplied within 60 s of immersion, the surface changes slowdown earlier and are visually less extensive than in uninhibited systems. Furthermore, our results highlight the potential of reflected microscopy for local corrosion inhibition studies and underscore the importance of understanding the interaction between inhibitor release timing and corrosion protection. •A reflected microscopy-based protocol for detailed visualization of local inhibitor deposition presented.•An analysis protocol of pixels activity is proposed to distinguish trenching and dealloying from inhibitor deposition.•Letting intermetallic particles dealloy for a brief period significantly affects Ce(III) capacity to precipitate.•Corrosion protection is not compromised when Ce(III) is supplied to the IMPs in our model system within 60 s of exposure.