Molecular modeling of the diffusion of ammonia through corrosion inhibitor films on copper

Ammonia is emerging as a carbon-free fuel but its corrosive effect on metal engine components, particularly those made of copper and copper alloys, is a major concern to be addressed. Herein, typical corrosion inhibitors are investigated in the presence of NH₃. They have been ranked experimentally based on their corrosion initiation time while the NH₃ diffusion barrier through inhibitor films has been evaluated using molecular dynamics simulations using a classical force field that was tuned to improve the Cu/inhibitor interactions. The excellent agreement with experiments indicates that this simulation approach could allow for the screening of new corrosion inhibitors.