Effect of Inhibitor Modifications on Initial Localized Dealloying of Metallic Alloy Surfaces

Abstract

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.