Astor Lectures: Corrosion - rust with 21st century tools.

The annual cost of corrosion is estimated to be more than 3% of the world’s GDP. While many of the broad details are known, there are still many gaps. Much of our current knowledge is from the mesoscale down to several nanometers, but multiple processes occur over wide spatial and temporal scales control the nucleation, stability, and utility of oxide scales. Creating quantitative models to disentangle the critical processes is not simple because of the time and costs of traditional experimental oxidation and corrosion studies. In the last decade there has been a convergence of forces creating the opportunity to reinvent our understanding of corrosion at the nanoscale. There has been an explosion of tools to image materials at the atomic scale and accurately calculate their behavior. Not only can single atoms be imaged, their chemical state can be measured. Modern ab-initio methods such as density functional theory are now starting to be able to handle materials such as transition metal oxides, where older functionals can go catastrophically wrong.
This presentation will discuss some of the fundamentals, what we understand, what we do not as well as recent progress of a group effort to bring the full power of these new tools to bear on corrosion at the atomic scale. I will cover three recent pieces of work: a) in-situ observations of the early stages of oxidation, b) DFT calculations which show a new mechanism of self-limited growth and c) how the fundamentals at the nanoscale matter for grain-boundary corrosion of CoCrMo implant materials.