| Abstract Scope |
Molten salt corrosion remains a key challenge for structural materials in advanced reactors and high-temperature energy systems. In this study, we develop and apply a reactive force field (ReaxFF) specifically tailored to model NiCr alloys in fluoride salt environments. This force field enables accurate atomistic simulations of interfacial redox reactions, capturing key factors that govern early-stage corrosion processes.
Using reactive molecular dynamics, we investigate the temperature-dependent corrosion behavior and identify surface-driven mechanisms, particularly Cr dissolution and surface diffusion, as the dominant contributors to corrosion progression. These reactions expose underlying Cr atoms, leading to sustained leaching into the molten salt. The simulations reproduce observed trends in corrosion rates as a function of Cr content in the alloy and the metal dissolution activation energy. We also examine how salt composition influences corrosion severity by modulating the redox environment at the interface.
Additionally, we explore the effects of surface orientation, grain boundaries, and applied mechanical stress. Notably, (111) and (100) surfaces exhibit improved resistance compared to (110), while intergranular corrosion is promoted by stronger F adsorption at grain boundary sites. Applied stress is found to change the corrosion mechanism, highlighting the complex interplay of mechanical and chemical factors.
Overall, these efforts provide mechanistic insights into molten salt corrosion and establish a basis for alloy/salt optimization through atomistic modeling. |