Despite a substantial number of reports on corrosion testing is available, only a few projects aim to understand the basic processes driving materials degradation. A special type of corrosion, localized dealloying, takes place on metallic alloy surfaces modified with self-assembled monolayers (SAMs) of organic inhibitors[1-2]. Corrosion initiation at the nanoscale can be addressed by controlling the spatial distribution and molecular organization of inhibitor-molecule SAMs at nano and micro length scales. We use micro-contact printing on model ultra-flat gold surfaces and obtain well-defined complex organic layers following a multi-step approach [3]. This approach was applied on locally atomically flat Cu₃Au (100) surfaces to study initial localized dealloying which results in the initiation of localized dealloying being strongly dependent on the nanoscale surface morphology (Figure 1) [4]. In addition, different organic inhibitors containing -SH (thiol end) films were subsequently applied on polycrystalline Cu and CuZn alloys to analyse inhibitor film stabilities. Force Spectroscopy of Atomic Force Microscopy (FS-AFM) provides a stability status of such inhibitor layers by analysing AFM tip sample force interaction on inhibitor-modified metallic surfaces.

References:

[1] B. R. Shrestha et al, Farad. Discuss. 180 (2015) 191–204.

[2] F. U. Renner et al, Adv. Mater. 27 (2015) 4877–4882.

[3] S. Neupane et al, Langmuir. 34 (2018) 66–72.

[4] S. Neupane et al, to be published.