Company / Speaker: University of Manchester / Dr.  Robert Lindsay
Zoom Event – More Information to follow

Corrosion Inhibition: Separating Fact from Fiction

For more than a century, surface-active organic species have been employed to control the corrosion of metals/alloys.  Given suitable selection, such corrosion inhibitors have proven to be highly effective, preventing significant degradation of metallic substrates even in highly aggressive environments.  Nevertheless, there are still considerable gaps in fundamental knowledge of corrosion inhibitor functionality, severely restricting further innovation.  For example, corrosion inhibition in acidic solutions is widely reported to be the result of the adsorption of a monolayer of surface-actives.  This description, however, can be considered to be largely a cartoon, as there is a significant lack of supporting experimental evidence.  Many key details remain uncertain, including the surface chemistry of the inhibited substrate, the structure of the adsorbed layer, and even its surface coverage.  Such information is key input for researchers attempting to predict corrosion inhibitor functionality through atomic scale interfacial modelling, and so identify next generation chemistries

In this presentation, following an introduction to corrosion inhibition in acidic solutions, I will discuss effort to reveal details of corrosion inhibitor-substrate interactions through detailed interface characterisation.  For example, I will discuss recent X-ray photoelectron spectroscopy (XPS) results, indicating that the chemistry of the inhibited interface is dependent on both inhibitor concentration and acid identity.  In addition, I will present data demonstrating that surface adsorption is not always sufficient for achieving the target corrosion inhibition efficiency, i.e. it will be shown that a surface-active can be bound to the surface, but not lead to sufficient reduction in corrosion rate.  Moreover, I will use XPS data to argue that the widely adopted approach of determining the standard Gibbs energy of adsorption of a corrosion inhibitor from measured inhibitor efficiencies is flawed, and so should not be relied upon as a tool for corrosion inhibitor selection