Offshore structures such as wind turbines and oil rigs generally comprise steel structures—essentially ferritic iron—and are extremely prone to corrosion, a problem that causes huge expenditure and often the use of noxious chemicals in an attempt to prevent it. Whilst various theories have been offered as to how to limit the corrosion process, the actual mechanism of corrosion and its dependence on the particular ionic species present remain poorly understood. Better understanding of the corrosion mechanisms and dependence on different environments and ion concentrations, as well as the mechanisms of inhibition offered by various potential inhibitors are badly needed to mitigate this problem in future. This proposal aims to use neutron reflectometry to characterise these corrosion and inhibition mechanisms whilst simultaneously characterising adsorbed additive layers in situ.